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this work reviews present knowledge of double-diffusive convection at low prandtl number obtained using direct numerical simulations, in both the fingering regime and the oscillatory regime. particular emphasis is given to modeling the induced turbulent mixing and its impact in various astrophysical applications. the nonlinear saturation of fingering convection at low prandtl number usually drives small-scale turbulent motions whose transport properties can be predicted reasonably accurately using a simple semi-analytical model. in some instances, large-scale internal gravity waves can be excited by a collective instability and eventually cause layering. the nonlinear saturation of oscillatory double-diffusive convection exhibits much more complex behavior. weakly stratified systems always spontaneously transition into layered convection associated with very efficient mixing. more strongly stratified systems remain dominated by weak wave turbulence unless they are initialized into a layered state. the effects of rotation, shear, lateral gradients, and magnetic fields are briefly discussed. | double-diffusive convection at low prandtl number |
we present a method for detection and reconstruction of the gravitational wave (gw) transients with the networks of advanced detectors. originally designed to search for transients with the initial gw detectors, it uses significantly improved algorithms, which enhance both the low-latency searches with rapid localization of gw events for the electromagnetic follow-up and high confidence detection of a broad range of the transient gw sources. in this paper, we present the analytic framework of the method. following a short description of the core analysis algorithms, we introduce a novel approach to the reconstruction of the gw polarization from a pattern of detector responses to a gw signal. this polarization pattern is a unique signature of an arbitrary gw signal that can be measured independently from the other source parameters. the polarization measurements enable rapid reconstruction of the gw waveforms, sky localization, and helps identification of the source origin. | method for detection and reconstruction of gravitational wave transients with networks of advanced detectors |
gravitational wave (gw) detection in space probes the gw spectrum that is inaccessible from the earth. in addition to the lisa project led by the european space agency, and the decigo detector proposed by the japan aerospace exploration agency, two chinese space-based gw observatories—tianqin and taiji—are planned to be launched in the 2030s. tianqin has a unique concept in its design with a geocentric orbit. taiji's design is similar to lisa, but is more ambitious with a longer arm distance. both facilities are complementary to lisa, considering that tianqin is sensitive to higher frequencies and taiji probes similar frequencies but with a higher sensitivity. in this perspective we explain the concepts of both facilities and introduce the development milestones of the tianqin and taiji projects in testing key technologies to pave the way for future space-based gw detections. considering that lisa, tianqin and taiji have similar scientific goals, are all scheduled to be launched around the 2030s and will operate concurrently, we discuss possible collaborations among them to improve gw source localization and characterization. | concepts and status of chinese space gravitational wave detection projects |
the proposed mission "space atomic gravity explorer" (sage) has the scientific objective to investigate gravitational waves, dark matter, and other fundamental aspects of gravity as well as the connection between gravitational physics and quantum physics using new quantum sensors, namely, optical atomic clocks and atom interferometers based on ultracold strontium atoms. | sage: a proposal for a space atomic gravity explorer |
a minimal extension of the standard model that provides both a dark matter candidate and a strong first-order electroweak phase transition (ewpt) consists of two additional lorentz and gauge singlets. in this paper we work out a composite higgs version of this scenario, based on the coset s o (7 )/s o (6 ). we show that by embedding the elementary fermions in appropriate representations of s o (7 ), all dominant interactions are described by only three free effective parameters. within the model dependencies of the embedding, the theory predicts one of the singlets to be stable and responsible for the observed dark matter abundance. at the same time, the second singlet introduces new c p -violation phases and triggers a strong first-order ewpt, making electroweak baryogenesis feasible. it turns out that this scenario does not conflict with current observations and it is promising for solving the dark matter and baryon asymmetry puzzles. the tight predictions of the model will be accessible at the forthcoming dark matter direct detection and gravitational wave experiments. | unified explanation for dark matter and electroweak baryogenesis with direct detection and gravitational wave signatures |
the study of cosmic phase transitions are of central interest in modern cosmology. in the standard model of cosmology the universe begins in a very hot state, right after at the end of inflation via the process of reheating/preheating, and cools to its present temperature as the universe expands. both new and existing physics at any scale can be responsible for catalyzing either first, second or cross over phase transition, which could be either thermal or non-thermal with a potential observable imprints. thus this field prompts a rich dialogue between gravity, particle physics and cosmology. it is all but certain that at least two cosmic phase transitions have occurred—the electroweak and the qcd phase transitions. the focus of this review will be primarily on phase transitions above such scales, we review different types of phase transitions that can appear in our cosmic history, and their applications and experimental signatures in particular in the context of exciting gravitational waves, which could be potentially be constrained by ligo/virgo, kagra, lisa, and decigo. | review of cosmic phase transitions: their significance and experimental signatures |
the characteristics of acoustic-gravity waves (waveforms, time durations, amplitudes, azimuths and horizontal phase speeds) from the eruption of the hunga-tonga-hunga-hapai volcano detected at different infrasound stations of the infrasound monitoring system and at a network of low-frequency microbarographs in the moscow region are studied. using the correlation analysis of the signals at different locations, six arrivals of signals from the volcano, which made up to two revolutions around the earth, were detected. the lamb mode of acoustic gravity waves from the volcano eruption is identified and the effect of this mode on generation of tsunami waves and variation of aerosol concentration is studied. the energy released from an underwater volcano into the atmosphere is estimated from the parameters of the lamb wave and compared with the energy released from the most powerful nuclear bomb of 58 mt tnt. | acoustic-gravity lamb waves from the eruption of the hunga-tonga-hunga-hapai volcano, its energy release and impact on aerosol concentrations and tsunami |
the primary goal of the second wind forecast improvement project (wfip2) is to advance the state-of-the-art of wind energy forecasting in complex terrain. to achieve this goal, a comprehensive 18-month field measurement campaign was conducted in the region of the columbia river basin. the observations were used to diagnose and quantify systematic forecast errors in the operational high-resolution rapid refresh (hrrr) model during weather events of particular concern to wind energy forecasting. examples of such events are cold pools, gap flows, thermal troughs/marine pushes, mountain waves, and topographic wakes. wfip2 model development has focused on the boundary layer and surface-layer schemes, cloud-radiation interaction, the representation of drag associated with subgrid-scale topography, and the representation of wind farms in the hrrr. additionally, refinements to numerical methods have helped to improve some of the common forecast error modes, especially the high wind speed biases associated with early erosion of mountain-valley cold pools. this study describes the model development and testing undertaken during wfip2 and demonstrates forecast improvements. specifically, wfip2 found that mean absolute errors in rotor-layer wind speed forecasts could be reduced by 5%-20% in winter by improving the turbulent mixing lengths, horizontal diffusion, and gravity wave drag. the model improvements made in wfip2 are also shown to be applicable to regions outside of complex terrain. ongoing and future challenges in model development will also be discussed. | improving wind energy forecasting through numerical weather prediction model development |
data from ground-based gravitational-wave detectors contains numerous short-duration instrumental artifacts, called 'glitches'. the high rate of these artifacts in turn results in a significant fraction of gravitational-wave signals from compact binary coalescences overlapping glitches. in ligo-virgo's third observing run, ≈20% of gravitational-wave source candidates required some form of mitigation due to glitches. this was the first observing run where glitch subtraction was included as a part of ligo-virgo-kagra data analysis methods for a large fraction of detected gravitational-wave events. this work describes the methods to identify glitches, the decision process for deciding if mitigation was necessary, and the two algorithms, bayeswave and gwsubtract, that were used to model and subtract glitches. through case studies of two events, gw190424_180648 and gw200129_065458, we evaluate the effectiveness of the glitch subtraction, compare the statistical uncertainties in the relevant glitch models, and identify potential limitations in these glitch subtraction methods. we finally outline the lessons learned from this first-of-its-kind effort for future observing runs. | subtracting glitches from gravitational-wave detector data during the third ligo-virgo observing run |
it is well known that the geometrical framework of riemannian geometry that underlies general relativity and its torsionful extension to riemann-cartan geometry can be obtained from a procedure known as gauging the poincaré algebra. recently it has been shown that gauging the centrally extended galilei algebra, known as the bargmann algebra, leads to a geometrical framework that when made dynamical gives rise to hořava-lifshitz gravity. here we consider the case where we contract the poincaré algebra by sending the speed of light to zero leading to the carroll algebra. we show how this algebra can be gauged and we construct the most general affine connection leading to the geometry of so-called carrollian space-times. carrollian space-times appear for example as the geometry on null hypersurfaces in a lorentzian space-time of one dimension higher. we also construct theories of ultra-relativistic (carrollian) gravity in 2+1 dimensions with dynamical exponent z < 1 including cases that have anisotropic weyl invariance for z = 0. | gauging the carroll algebra and ultra-relativistic gravity |
we show that a minimal scenario, utilizing only the graviton as an intermediate messenger between the inflaton, the dark sector and the standard model (sm), is able to generate simultaneously the observed relic density of dark matter (dm), the baryon asymmetry through leptogenesis, as well as a sufficiently hot thermal bath after inflation. we assume an inflaton potential of the form v(ϕ) ∝ ϕk about the minimum at the end of inflation. the possibility of reheating via minimal gravitational interactions has been excluded by constraints on dark radiation for excessive gravitational waves produced from inflation. we thus extend the minimal model in several ways: i) we consider non-minimal gravitational couplings — this points to the parameter range of dm masses mn1 ≃ 2-10 pev, and right-handed neutrino masses mn 2 ≃ (5-20) × 1011 gev, and trh ≲ 3 × 105 gev (for k ≤ 20); ii) we propose an explanation for the pev excess observed by icecube when the dm has a direct but small yukawa coupling to the sm; and iii) we also propose a novel scenario, where the gravitational production of dm is a two-step process, first through the production of two scalars, which then decay to fermionic dm final states. in this case, the absence of a helicity suppression enhances the production of dm and baryon asymmetry, and allows a great range for the parameters including a dark matter mass below an mev where dark matter warmness can be observable by cosmic 21-cm lines, even when gravitational interactions are responsible for reheating. we also show that detectable primordial gravitational wave signals provide the opportunity to probe this scenario for trh ≲ 5 × 106 gev in future experiments, such as bbo, decigo, ce and et. | gravity as a portal to reheating, leptogenesis and dark matter |
we explore the gravitational wave spectrum generated by string-wall structures in an so (10) (spin (10)) based scenario of pseudo-goldstone boson dark matter (pgdm) particle. this dark matter candidate is a linear combination of the standard model (sm) singlets present in the 126 and 16 dimensional higgs fields. the higgs 126-plet vacuum expectation value (vev) «126h » leaves unbroken the z2 subgroup of z4, the center of so (10). among other things, this yields topologically stable cosmic strings with a string tension μ ∼«126h » 2. the subsequent (spontaneous) breaking of z2 at a significantly lower scale by the 16-plet vev «16h » leads to the appearance of domain walls bounded by the strings produced earlier. we display the gravitational wave spectrum for gμ values varying between 10-15 and 10-9 («126h » ∼1011 - 1014 gev), and «16h » ∼ 0.1 - 102 tev range (g denotes newton's constant.) these predictions can be tested, as we show, by a variety of (proposed) experiments including lisa, et, ce and others. | gravitational waves from walls bounded by strings in so(10) model of pseudo-goldstone dark matter |
miniaturized mechanical sensors rely on resonant operation schemes, unsuited to detect static forces. we demonstrate a nanomechanical sensor for static forces based on an optically trapped nanoparticle in vacuum. our technique relies on an off-resonant interaction of the particle with a weak static force, and a resonant readout of the displacement caused by this interaction. we demonstrate a sensitivity of 10 an to static gravitational and electric forces. our work provides a tool for the closer investigation of short-range forces, and marks an important step towards the realization of matter-wave interferometry with macroscopic objects. | sensing static forces with free-falling nanoparticles |
we investigate the production process of induced gravity waves due to large scalar fluctuations in the paradigm of quintessential inflation. we numerically solve the mukhanov-sasaki equation for different sets of parameters to obtain the power spectra. we demonstrate that the induced gravity wave signal generated in this framework can fall within the region of the nanograv data for chosen values of model parameters. we show that there is an allowed region of parameter space where the effect shifts to the high-frequency regime relevant to the laser interferometer space antenna and other available sensitivities. | gravitational wave background from quintessential inflation and nanograv data |
we study the gravitational radiation emitted during the scattering of two spinless bodies in the post-minkowskian effective field theory approach. we derive the conserved stress-energy tensor linearly coupled to gravity and the classical probability amplitude of graviton emission at leading and next-to-leading order in the newton's constant g . the amplitude can be expressed in compact form as one-dimensional integrals over a feynman parameter involving bessel functions. we use it to recover the leading-order radiated angular momentum expression. upon expanding it in the relative velocity between the two bodies v , we compute the total four-momentum radiated into gravitational waves at leading-order in g and up to an order v, 8 finding agreement with what was recently computed using scattering amplitude methods. our results also allow us to investigate the zero frequency limit of the emitted energy spectrum. | gravitational bremsstrahlung in the post-minkowskian effective field theory |
we present the first end-to-end nonperturbative analysis of the gravitational wave power spectrum from a thermal first-order electroweak phase transition (ewpt), using the framework of dimensionally reduced effective field theory and preexisting nonperturbative simulation results. we are able to show that a first-order ewpt in any beyond the standard model (bsm) scenario that can be described by a standard model-like effective theory at long distances will produce gravitational wave signatures too weak to be observed at existing and planned detectors. this implies that colliders are likely to provide the best chance of exploring the phase structure of such theories, while transitions strong enough to be detected at gravitational wave experiments require either previously neglected higher-dimension operators or light bsm fields to be included in the dimensionally reduced effective theory and therefore necessitate dedicated nonperturbative studies. as a concrete application, we analyze the real singlet-extended standard model and identify regions of parameter space with single-step first-order transitions, comparing our findings to those obtained using a fully perturbative method. we discuss the prospects for exploring the electroweak phase diagram in this model at collider and gravitational wave experiments in light of our nonperturbative results. | nonperturbative analysis of the gravitational waves from a first-order electroweak phase transition |
"this book is devoted to researchers who would like to investigate interactions among gravitational waves and matter fields beyond linear order, including the phenomena of memory effects, gravitational faraday rotation, soft theorems, and formations of spacetime singularities due to the mutual focus of gravitational waves. readers only require a basic understanding of general relativity to understand the materials. the book starts with an overview on the fundamentals of the newman-penrose formalism and a brief introduction to distribution theory, with which the author systematically develops a mathematical description of spacetimes of colliding plane waves. then, the author presents a frame-independent definition of polarization of a plane gravitational wave in a curved spacetime, studies in detail the gravitational faraday rotation of two plane gravitational waves, and shows that each of them can serve as a medium to the other precisely due to their nonlinear interactions. exact solutions are also presented, which represent a variety of models including the collisions of two plane gravitational waves and the collisions of a plane gravitational wave with a dust shell, a massless scalar wave, an electromagnetic wave, or a neutrino wave. the formation of spacetime singularities due to nonlinear interactions and the effects of gravitational wave polarization on the nature of singularities are also explored"--publisher's website. | interacting gravitational, electromagnetic, neutrino and other waves: in the context of einstein's general theory of relativity |
the microphysical and radiative properties of cirrus clouds continue to be beyond understanding and thus still represent one of the largest uncertainties in the prediction of the earth's climate (ipcc, 2013). our study aims to provide a guide to cirrus microphysics, which is compiled from an extensive set of model simulations, covering the broad range of atmospheric conditions for cirrus formation and evolution. the model results are portrayed in the same parameter space as field measurements, i.e., in the ice water content-temperature (iwc-t) parameter space. we validate this cirrus analysis approach by evaluating cirrus data sets from 17 aircraft campaigns, conducted in the last 15 years, spending about 94 h in cirrus over europe, australia, brazil as well as south and north america. altogether, the approach of this study is to track cirrus iwc development with temperature by means of model simulations, compare with observations and then assign, to a certain degree, cirrus microphysics to the observations. indeed, the field observations show characteristics expected from the simulated cirrus guide. for example, high (low) iwcs are found together with high (low) ice crystal concentrations nice.an important finding from our study is the classification of two types of cirrus with differing formation mechanisms and microphysical properties: the first cirrus type forms directly as ice (in situ origin cirrus) and splits in two subclasses, depending on the prevailing strength of the updraft: in slow updrafts these cirrus are rather thin with lower iwcs, while in fast updrafts thicker cirrus with higher iwcs can form. the second type consists predominantly of thick cirrus originating from mixed phase clouds (i.e., via freezing of liquid droplets - liquid origin cirrus), which are completely glaciated while lifting to the cirrus formation temperature region (< 235 k). in the european field campaigns, slow updraft in situ origin cirrus occur frequently in low- and high-pressure systems, while fast updraft in situ cirrus appear in conjunction with jet streams or gravity waves. also, liquid origin cirrus mostly related to warm conveyor belts are found. in the us and tropical campaigns, thick liquid origin cirrus which are formed in large convective systems are detected more frequently. | a microphysics guide to cirrus clouds - part 1: cirrus types |
we analyze the stratospheric waves in models participating in phase 1 of the stratosphere-troposphere processes and their role in climate (sparc) quasi-biennial oscillation initiative (qboi). all models have robust kelvin and mixed rossby-gravity wave modes in winds and temperatures at 50 hpa and represent them better than most of the coupled model intercomparison project phase 5 (cmip5) models. there is still some spread among the models, especially concerning the mixed rossby-gravity waves. we attribute the variability in equatorial waves among the qboi models in part to the varying horizontal and vertical resolutions, to systematic biases in zonal winds, and to the considerable variability in convectively coupled waves in the troposphere among the models: only roughly half of the qboi models have realistic convectively coupled kelvin waves and only a few models have convectively coupled mixed rossby-gravity waves. the models with stronger convectively coupled waves tend to produce larger zonal mean forcing due to resolved waves in the qbo region. finally we evaluate the eliassen-palm (ep) flux and ep flux divergence of the resolved waves in the qboi models. we find that there is a large spread in the forcing from resolved waves in the qbo region, and the resolved wave forcing has a robust correlation with model vertical resolution. | an evaluation of tropical waves and wave forcing of the qbo in the qboi models |
the last decade has seen a significant increase in the number of studies devoted to wave turbulence. many deal with water waves, as modeling of ocean waves has historically motivated the development of weak turbulence theory, which addresses the dynamics of a random ensemble of weakly nonlinear waves in interaction. recent advances in experiments have shown that this theoretical picture is too idealized to capture experimental observations. while gravity dominates much of the oceanic spectrum, waves observed in the laboratory are in fact gravity-capillary waves, due to the restricted size of wave basins. this richer physics induces many interleaved physical effects far beyond the theoretical framework, notably in the vicinity of the gravity-capillary crossover. these include dissipation, finite-system size effects, and finite nonlinearity effects. simultaneous space-and-time-resolved techniques, now available, open the way for a much more advanced analysis of these effects. | experiments in surface gravity-capillary wave turbulence |
we present a new global thermochemical model of the lithosphere and underlying upper mantle constrained by state of the art seismic waveform inversion, satellite gravity (geoid and gravity anomalies and gradiometric measurements from esa's goce mission), surface elevation and heat flow data: winterc-g. the model is based upon an integrated geophysical-petrological approach where seismic velocities and density in the mantle are computed within a thermodynamically self-consistent framework, allowing for a direct parametrization in terms of the temperature and composition variables. the complementary sensitivities of the data sets allow us to constrain the geometry of the lithosphere-asthenosphere boundary, to separate thermal and compositional anomalies in the mantle, and to obtain a proxy for dynamic surface topography. at long spatial wavelengths, our model is generally consistent with previous seismic (or seismically derived) global models and earlier integrated studies incorporating surface wave data at lower lateral resolution. at finer scales, the temperature, composition and density distributions in winterc-g offer a new state of the art image at a high resolution globally (225 km average interknot spacing). our model shows that the deepest lithosphere-asthenosphere boundary is associated with cratons and, also, some tectonically active areas (andes, persian gulf). among cratons we identify considerable differences in temperature and composition. the north american and siberian cratons are thick (>260 km) and compositionally refractory, whereas the sino-korean, aldan and tanzanian cratons have a thinner, fertile lithosphere, similar to younger continental lithosphere elsewhere. winterc-g shows progressive thickening of oceanic lithosphere with age, but with significant regional differences: the lithospheric mantle beneath the atlantic and indian oceans is, on average, colder, more fertile and denser than that beneath the pacific ocean. our results suggest that the composition, temperature and density of the oceanic mantle lithosphere are related to the spreading rate for the rates up to 50-60 mm yr-1: the lower spreading rate, the higher the mantle fertility and density, and the lower the temperature. at greater spreading rates, the relationship disappears. the 1-d radial average of winterc-g displays a mantle geothermal gradient of 0.55-0.6 k km-1 and a potential temperature of 1300-1320 °c for depths >200 km. at the top of the mantle transition zone the amplitude of the maximum lateral temperature variations (cratons versus hotspots) is about 120 k. the isostatic residual topography values, a proxy for dynamic topography, are large (>1 km) mostly in active subduction settings. the residual isostatic bathymetry from winterc-g is remarkably similar to the pattern independently determined based on oceanic crustal data compilations. the amplitude of the continental residual topography is relatively large and positive (>600 m) in the east european craton, greenland, and the andes and himalayas. by contrast, central asia, most of antarctica, southern south america and, to a lesser extent, central africa are characterized by negative residual topography values (>-400 m). our results show that a substantial part of the topography signal previously identified as residual (or dynamic) is accounted for, isostatically, by lithospheric density variations. | winterc-g: mapping the upper mantle thermochemical heterogeneity from coupled geophysical-petrological inversion of seismic waveforms, heat flow, surface elevation and gravity satellite data |
domain walls (dws) from spontaneously breaking of the discrete symmetry in approximate $z_3$-invariant nmssm can collapse and lead to the stochastic gravitational waves (gws) background signals observed by pta collaborations with the presence of some explicitly $z_3$ breaking terms in the nmssm effective superpotential and scalar potential. in the presence of a hidden sector, such terms may origin from the geometric superconformal breaking with holomorphic quadratic correction to frame function when the global scale-invariant superpotential is naturally embedded into the canonical superconformal supergravity models. the smallness of such mass parameters in the nmssm may be traced back to the original superconformal invariance. naive estimations indicate that susy explanation to muon $g-2$ anomaly can have tension with the constraints on susy by pta data, because large susy contributions to $\delta a_\mu$ in general needs relatively light superpartners while present $\omega_{gw}^0$ can set the lower bounds for $m_{soft}$. we calculate numerically the signatures of gws produced from the collapse of dws and find that the observed nhz stochastic gws background by nanograv etc can indeed be explained with proper tiny values of $\chi m_{3/2}\sim 10^{-14}{\rm ev}$ for $\chi s^2$ case (and $\chi m_{3/2}\sim 10^{-10}{\rm ev}$ for $\chi h_u h_d$ case), respectively. besides, there are still some parameter points, whose gws spectra intersect with the nanograv signal region, can explain the muon $g-2$ anomaly to $1\sigma$ range. | the interplay between the muon $g-2$ anomaly and the pta nhz gravitational waves from domain walls in nmssm |
in this work, we propose a model of einstein--gauss-bonnet gravity coupled with two scalar fields. the two scalar fields are considered to be ``frozen'' or they become non-dynamical by employing appropriate constraints in terms of lagrange multiplier fields. we show that, even in the case that the arbitrary spherically symmetric spacetime is dynamical, we can construct a model where the wormhole spacetime is a stable solution in this framework. we especially concentrate on the model reproducing the dynamical wormhole, where the wormhole appears in a finite-time interval. we investigate the propagation of the gravitational wave in the wormhole spacetime background and we show that the propagation speed is different from that of light $\to$ light in general, and there is a difference in the speeds between the incoming propagating wave and the outgoing propagating gravitational wave. | propagation of gravitational waves in a dynamical wormhole background for two-scalar einstein-gauss-bonnet theory |
the raw outputs of the detectors within the advanced laser interferometer gravitational-wave observatory need to be calibrated in order to produce the estimate of the dimensionless strain used for astrophysical analyses. the two detectors have been upgraded since the second observing run and finished the year-long third observing run. understanding, accounting, and/or compensating for the complex-valued response of each part of the upgraded detectors improves the overall accuracy of the estimated detector response to gravitational waves. we describe improved understanding and methods used to quantify the response of each detector, with a dedicated effort to define all places where systematic error plays a role. we use the detectors as they stand in the first half (six months) of the third observing run to demonstrate how each identified systematic error impacts the estimated strain and constrain the statistical uncertainty therein. for this time period, we estimate the upper limit on systematic error and associated uncertainty to be <7% in magnitude and <4 deg in phase (68% confidence interval) in the most sensitive frequency band 20-2000 hz. the systematic error alone is estimated at levels of <2% in magnitude and <2 deg in phase. | characterization of systematic error in advanced ligo calibration |
this work investigates a simple, representative extension of the standard model with a real scalar singlet and spontaneous z2 breaking, which allows for a strongly first-order phase transition, as required by electroweak baryogenesis. we perform analytical and numerical calculations that systematically include one-loop thermal effects, coleman-weinberg corrections, and daisy resummation, as well as evaluation of bubble nucleation. we study the rich thermal history and identify the conditions for a strongly first-order electroweak phase transition with nearly degenerate extrema at zero temperature. this requires a light scalar with mass below 50 gev. exotic higgs decays, as well as higgs coupling precision measurements at the lhc and future collider facilities, will test this model. additional information may be obtained from future collider constraints on the higgs self-coupling. gravitational-wave signals are typically too low to be probed by future gravitational wave experiments. | electroweak phase transition with spontaneous z2-breaking |
in this paper we present the enhanced x-ray timing and polarimetry mission—extp. extp is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. the mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of qed, and understanding the dynamics of matter in strong-field gravity. in addition to investigating fundamental physics, extp will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. in particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources. the paper provides a detailed description of: (1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload; (2) the elements and functions of the mission, from the spacecraft to the ground segment. | the enhanced x-ray timing and polarimetry mission—extp |
following a semiclassical eikonal approach—justified at transplanckian energies order by order in the deflection angle θs∼4/g √{s } b ≡2/r b —we investigate the infrared features of gravitational scattering and radiation in four space-time dimensions, and we illustrate the factorization and cancellation of the infinite coulomb phase for scattering and the eikonal resummation for radiation. as a consequence, both the eikonal phase 2 δ (e ,b ) and the gravitational-wave (gw) spectrum d/egw d ω are free from infrared problems in a frequency region extending from zero to (and possibly beyond) ω =1 /r . the infrared-singular behavior of 4-d gravity leaves a memory in the deep infrared region (ω r ≪ω b <1 ) of the spectrum. at o (ω b ) we confirm the presence of logarithmic enhancements of the form already pointed out by sen and collaborators on the basis of nonleading corrections to soft-graviton theorems. these, however, do not contribute to the unpolarized and/or azimuthally averaged flux. at o (ω2b2 ) we find instead a positive logarithmically enhanced correction to the total flux implying an unexpected maximum of its spectrum at ω b ∼0.5 . at higher orders we find subleading enhanced contributions as well, which can be resummed, and have the interpretation of a finite rescattering coulomb phase of emitted gravitons. | infrared features of gravitational scattering and radiation in the eikonal approach |
we present submachine, a collection of web-based tools for the interactive visualization, analysis, and quantitative comparison of global-scale data sets of the earth's interior. submachine focuses on making regional and global-scale seismic tomography models easily accessible to the wider solid earth community, in order to facilitate collaborative exploration. we have written software tools to visualize and explore over 30 tomography models—individually, side-by-side, or through statistical and averaging tools. submachine also serves various nontomographic data sets that are pertinent to the interpretation of mantle structure and complement the tomographies. these include plate reconstruction models, normal mode observations, global crustal structure, shear wave splitting, as well as geoid, marine gravity, vertical gravity gradients, and global topography in adjustable degrees of spherical harmonic resolution. by providing repository infrastructure, submachine encourages and supports community contributions via submission of data sets or feedback on the implemented toolkits. | submachine: web-based tools for exploring seismic tomography and other models of earth's deep interior |
waveforms are classical observables associated with any radiative physical process. using scattering amplitudes, these are usually computed in a weak-field regime to some finite order in the post-newtonian or post-minkowskian approximation. here, we use strong-field amplitudes to compute the waveform produced in scattering of massive particles on gravitational plane waves, treated as exact nonlinear solutions of the vacuum einstein equations. notably, the waveform contains an infinite number of post-minkowskian contributions, as well as tail effects. we also provide, and contrast with, analogous results in electromagnetism. | all order gravitational waveforms from scattering amplitudes |
a stochastic gravitational wave background is a prediction of a number of astrophysical and cosmological phenomena including early universe cosmology. recently, the nanograv collaboration reported conclusive evidence for a stochastic gravitational wave background. we analyze the nanograv signal, assuming it is of primordial origin, including the reheating phase. we use the latest measurements from nanograv to constrain the universe's reheating equation of state wre, the reheating temperature tre, the tensor-to-scalar ratio r , and the tensor tilt nt. assuming the constant equation of state wre to be responsible for the reheating phase, we find a preference for instant reheating, wre=0.3 6-0.28+0.15 , and a very blue tilt nt=1.9 4-0.88+0.43 . we find a degeneracy between the tensor-to-scalar ratio r and tre and suggest ways to break this degeneracy. in all cases where the reheating temperature is constrained, it is constrained to be very low, with tre≤105 gev . we further find that a scale-invariant spectrum, as suggested by inflation, implies a stiff equation of state wre=19 /3 . if extrapolated, the blue-tilted primordial spectrum that agrees with the nanograv signal at corresponding frequencies is incompatible with the ligo bound. this incompatibility is another challenge for connecting nanograv with the primordial spectrum. we discuss a number of ways to circumvent this issue. we split the spectrum into a sum of astrophysical and primordial spectra and constrain the astrophysical and primordial components using nanograv data and the ligo bound. in another attempt, we use the same data and constrain the running of the spectrum. any of these, or a combination of such methods, can be used to reconcile the nanograv data and the ligo bound with the primordial power spectrum. | probing the early universe cosmology with nanograv: possibilities and limitations |
we study the gravitational-wave signal stemming from strongly coupled models featuring both, dark chiral and confinement phase transitions. we therefore identify strongly coupled theories that can feature a first-order phase transition. employing the polyakov-nambu-jona-lasinio model, we focus our attention on su(3) yang-mills theories featuring fermions in fundamental, adjoint, and two-index symmetric representations. we discover that for the gravitational-wave signals analysis, there are significant differences between the various representations. interestingly we also observe that the two-index symmetric representation leads to the strongest first-order phase transition and therefore to a higher chance of being detected by the big bang observer experiment. our study of the confinement and chiral phase transitions is further applicable to extensions of the standard model featuring composite dynamics. | dark confinement and chiral phase transitions: gravitational waves vs matter representations |
we perform direct numerical simulations of magnetohydrodynamic turbulence in the early universe and numerically compute the resulting stochastic background of gravitational waves and relic magnetic fields. these simulations do not make the simplifying assumptions of earlier analytic work. if the turbulence is assumed to have an energy-carrying scale that is about a hundredth of the hubble radius at the time of generation, as expected in a first-order phase transition, the peak of gravitational wave power will be in the mhz frequency range for a signal produced at the electroweak scale. the efficiency of gravitational wave (gw) production varies significantly with how the turbulence is driven. detectability of turbulence at the electroweak scale by the planned laser interferometer space antenna (lisa) requires anywhere from 0.1% to 10% of the thermal plasma energy density to be in plasma motions or magnetic fields, depending on the model of the driving process. our results predict a new universal form below the spectral peak frequency that is shallower than previously thought. this implies larger values of the gw energy spectra in the low-frequency range. this extends the range where turbulence is detectable with lisa to lower frequencies, corresponding to higher energy scales than the assumed energy-carrying scale. | numerical simulations of gravitational waves from early-universe turbulence |
we suggest an appealing strategy to probe a large class of scenarios beyond the standard model simultaneously explaining the recent cdf ii measurement of the w boson mass and predicting first-order phase transitions (fopt) testable in future gravitational-wave (gw) experiments. our analysis deploys measurements from the gw channels and high energy particle colliders. we discuss this methodology focusing on the specific example provided by an extension of the standard model of particle physics that incorporates an additional scalar su(2) l triplet coupled to the higgs boson. we show that within this scenario a strong electroweak fopt is naturally realised consistently with the measured w boson mass-shift. potentially observable gw signatures imply the triplet mass scale to be tev-ish, consistently with the value preferred by the w mass anomaly. this model can be tested in future space-based interferometers such as lisa, decigo, bbo, tianqin, taiji projects and in future colliders such as fcc, ilc, cepc. | cdf ii w-mass anomaly faces first-order electroweak phase transition |
we study gravitational shock waves using scattering amplitude techniques. after first reviewing the derivation in general relativity as an ultrarelativistic boost of a schwarzschild solution, we provide an alternative derivation by exploiting a novel relation between scattering amplitudes and solutions to einstein field equations. we prove that gravitational shock waves arise from the classical part of a three point function with two massless scalars and a graviton. the region where radiation is localized has a distributional profile and it is now recovered in a natural way, thus bypassing the introduction of singular coordinate transformations as used in general relativity. the computation is easily generalized to arbitrary dimensions and we show how the exactness of the classical solution follows from the absence of classical contributions at higher loops. a classical double copy between gravitational and electromagnetic shock waves is also provided and for a spinning source, using the exponential form of three point amplitudes, we infer a remarkable relation between gravitational shock waves and spinning ones, also known as gyratons. using this property, we infer a family of exact solutions describing gravitational shock waves with spin. we then compute the phase shift of a particle in a background of shock waves finding agreement with an earlier computation by amati, ciafaloni and veneziano for particles in the high energy limit. applied to a gyraton, it provides a result for the scattering angle to all orders in spin. | gravitational shock waves and scattering amplitudes |
we explore a variety of composite topological structures that arise from the spontaneous breaking of so(10) to su(3)c× u(1)em via one of its maximal subgroups su(5) × u(1)χ, su(4)c× su(2)l× su(2)r, and su(5) × u(1)x (also known as flipped su(5)). they include i) a network of &z; strings which develop monopoles and turn into necklaces with the structure of &z;2 strings, ii) dumbbells connecting two different types of monopoles, or monopoles and antimonpoles, iii) starfish-like configurations, iv) polypole configurations, and v) walls bounded by a necklace. we display these structures both before and after the electroweak breaking. the appearance of these composite structures in the early universe and their astrophysical implications including gravitational wave emission would depend on the symmetry breaking patterns and scales, and the nature of the associated phase transitions. | composite topological structures in so(10) |
the recent nanograv evidence of a common-source stochastic background provides a hint to gravitational waves (gw) radiation from the early universe. we show that this result can be interpreted as a gw spectrum produced from first order phase transitions (fopts) around a temperature in the kev-mev window. such a class of fopts at temperatures much below the electroweak scale can be naturally envisaged in several warm dark matter models such as majoron dark matter. | nanograv results and dark first order phase transitions |
recent progress in observing and manipulating mechanical oscillators at quantum regime provides new opportunities of studying fundamental physics, for example to search for low energy signatures of quantum gravity. for example, it was recently proposed that such devices can be used to test quantum gravity effects, by detecting the change in the [x ^,p ^] commutation relation that could result from quantum gravity corrections. we show that such a correction results in a dependence of a resonant frequency of a mechanical oscillator on its amplitude, which is known as the amplitude-frequency effect. by implementing this new method we measure the amplitude-frequency effect for a 0.3 kg ultra-high-q sapphire split-bar mechanical resonator and for an ∼10-5 kg quartz bulk acoustic wave resonator. our experiments with a sapphire resonator have established the upper limit on a quantum gravity correction constant of β0 to not exceed 5.2 ×106, which is a factor of 6 better than previously measured. the reasonable estimates of β0 from experiments with quartz resonators yields β0<4 ×104. the datasets of 1936 measurements of a physical pendulum period by atkinson [e. c. atkinson, proc. phys. soc. london 48, 606 (1936)., 10.1088/0959-5309/48/4/307] could potentially lead to significantly stronger limitations on β0≪1 . yet, due to the lack of proper pendulum frequency stability measurement in these experiments the exact upper bound on β0 cannot be reliably established. moreover, pendulum based systems only allow one to test a specific form of the modified commutator that depends on the mean value of momentum. the electromechanical oscillators to the contrary enable testing of any form of generalized uncertainty principle directly due to a much higher stability and a higher degree of control. | testing the generalized uncertainty principle with macroscopic mechanical oscillators and pendulums |
the post-minkowskian expansion of einstein's general theory of relativity has received much attention in recent years due to the possibility of harnessing the computational power of modern amplitude calculations in such a classical context. in this brief review, we focus on the post-minkowskian expansion as applied to the two-body problem in general relativity without spin, and we describe how relativistic quantum field theory can be used to greatly simplify analytical calculations based on the einstein-hilbert action. subtleties related to the extraction of classical physics from such quantum mechanical calculations highlight the care which must be taken when both positive and negative powers of planck's constant are at play. in the process of obtaining classical results in both einstein gravity and supergravity, one learns new aspects of quantum field theory that are obscured when using units in which planck's constant is set to unity. the scattering amplitude approach provides a self-contained framework for deriving the two-body scattering valid in all regimes of energy. there is hope that the full impact of amplitude computations in this field may significantly alter the way in which gravitational wave predictions will advance in the coming years. | the sagex review on scattering amplitudes, chapter 13: post-minkowskian expansion from scattering amplitudes |
we update predictions for the gravitational wave (gw) signal from a strongly supercooled phase transition in an illustrative classically conformal u(1)b-l model. we implement propto γ2 scaling of the friction on the bubble wall and update the estimates for the efficiency factors for gw production from bubble collisions and plasma-related sources. we take into account the fact that a small decay rate of the symmetry-breaking field may lead to brief matter-dominated era after the transition, as the field oscillates around its minimum before decaying. we find that a strong bubble collision signal occurs in a significant part of the parameter space, and that the modified redshift of the modes that re-enter the horizon during the matter-dominated period generates a characteristic tilted 'plateau' in the spectrum. the gw spectrum in this model would be detectable in the low-frequency range, e.g., by lisa, and in the mid-frequency range, e.g., by aion/magis and aedge, and in the high-frequency range by ligo and et. the peak frequency of the signal is limited from below by collider constraints on the mass of the u(1)b-l gauge boson, while at high frequencies the slow decay of the scalar field and the resulting matter-dominated era diminishes the gw signal. | updated predictions for gravitational waves produced in a strongly supercooled phase transition |
thermal corrections in classically conformal models typically induce a strong first-order electroweak phase transition, thereby resulting in a stochastic gravitational background that could be detectable at gravitational wave observatories. after reviewing the basics of classically conformal scenarios, in this paper we investigate the phase transition dynamics in a thermal environment and the related gravitational wave phenomenology within the framework of scalar conformal extensions of the standard model. we find that minimal extensions involving only one additional scalar field struggle to reproduce the correct phase transition dynamics once thermal corrections are accounted for. next-to-minimal models, instead, yield the desired electroweak symmetry breaking and typically result in a very strong gravitational wave signal. | phase transition and gravitational wave phenomenology of scalar conformal extensions of the standard model |
we construct a single-field model of inflation that achieves remarkable agreement with planck and bicep/keck cosmological observations. the model, via the presence of an ultraslow-roll phase, generates a sizable scalar-induced gravitational wave (gw) signal at nhz frequencies. we elucidate the distinctive features of this signal concerning its connection to the recent measurement of the low-frequency gw background reported by the nanograv collaboration. | inflationary interpretation of the nhz gravitational-wave background |
we propose an experiment to search for ultralight scalar dark matter (dm) with dilatonic interactions. such couplings can arise for the dilaton as well as for moduli and axion-like particles in the presence of c p violation. ultralight dilaton dm acts as a background field that can cause tiny but coherent oscillations in standard model parameters such as the fine-structure constant and the proton-electron mass ratio. these minute variations can be detected through precise frequency comparisons of atomic clocks. our experiment extends current searches for drifts in fundamental constants to the well-motivated high-frequency regime. our proposed setups can probe scalars lighter than 1 0-15 ev with a discovery potential of dilatonic couplings as weak as 1 0-11 times the strength of gravity, improving current equivalence principle bounds by up to 8 orders of magnitude. we point out potential 1 04 sensitivity enhancements with future optical and nuclear clocks, as well as possible signatures in gravitational-wave detectors. finally, we discuss cosmological constraints and astrophysical hints of ultralight scalar dm, and show they are complimentary to and compatible with the parameter range accessible to our proposed laboratory experiments. | searching for dilaton dark matter with atomic clocks |
we present the fastemriwaveforms (few) package, a collection of tools to build and analyze extreme mass ratio inspiral (emri) waveforms. here, we expand on [a. j. k. chua et al., phys. rev. lett. 126, 051102 (2021)., 10.1103/physrevlett.126.051102] that introduced the first fast and accurate fully-relativistic emri waveform template model. we discuss the construction of the overall framework; constituent modules; and the general methods used to accelerate emri waveforms. because the fully relativistic few model waveforms are for now limited to eccentric orbits in the schwarzschild spacetime, we also introduce an improved augmented analytic kludge (aak) model that describes generic kerr inspirals. both waveform models can be accelerated using graphics processing unit (gpu) hardware. with the gpu-accelerated waveforms in hand, a variety of studies are performed including an analysis of emri mode content, template mismatch, and fully bayesian markov chain monte carlo-based emri parameter estimation. we find relativistic emri waveform templates can be generated with fewer harmonic modes (∼10 - 100 ) without biasing signal extraction. however, we show for the first time that extraction of a relativistic injection with semirelativistic amplitudes can lead to strong bias and anomalous structure in the posterior distribution for certain regions of parameter space. | fast extreme-mass-ratio-inspiral waveforms: new tools for millihertz gravitational-wave data analysis |
if the electroweak phase transition (ewpt) is of strongly first order due to higher dimensional operators, the scale of new physics generating them is at the tev scale or below. in this case the effective-field theory (eft) neglecting operators of dimension higher than six may overlook terms that are relevant for the ewpt analysis. in this article we study the ewpt in the eft to dimension eight. we estimate the reach of the future gravitational wave observatory lisa for probing the region in which the ewpt is strongly first order and compare it with the capabilities of the higgs measurements via double-higgs production at current and future colliders. we also match different uv models to the previously mentioned dimension-eight eft and demonstrate that, from the top-down point of view, the double-higgs production is not the best signal to explore these scenarios. | signals of the electroweak phase transition at colliders and gravitational wave observatories |
in this paper we study both projective and non-projective constraints on four-dimensional gravitational effective fields theories implied from unitarity, causality and crossing, assuming perturbative uv completions in $m_{\rm pl}$. we derive bounds on the wilson coefficients of $r^3$ and $d^{2n}r^4$ from its dispersive representation, utilizing both numerical semi-definite programming and analytic geometry analysis. from the former, we derive projective bounds on ratios of couplings and observe accumulation point spectrum populating the boundary of the allowed region. for the latter we consider the non-projective geometry of the efthedron, which we relate to the known $l$-moment problem in the literature. this allows us to move beyond positivity and incorporate the upper bound from unitarity of the imaginary parts of partial waves. this leads to sharp bounds on individual coefficients, which are of order unity when normalized with respect to the uv scale. finally, the non-projective geometry also allows us to derive optimal bounds reflecting assumptions of low-spin dominance, improving previous results. we complement the analytic analysis with a simple linear programming approach that validates the bounds. | (non)-projective bounds on gravitational eft |
in this work, we find the light front densities for momentum and forces, including pressure and shear forces, within hadrons. this is achieved by deriving relativistically correct expressions relating these densities to the gravitational form factors a (t ) and d (t ) associated with the energy momentum tensor. the derivation begins from the fundamental definition of density in a quantum field theory, namely the expectation value of a local operator within a spatially localized state. we find that it is necessary to use the light front formalism to define a density that corresponds to the internal hadron structure. when using the instant form formalism, it is impossible to remove the spatial extent of the hadron wave function from any density, and—even within instant form dynamics—one does not obtain a breit frame fourier transform for a properly defined density. within the front formalism, we derive new expressions for various mechanical properties of hadrons, including the mechanical radius, as well as for stability conditions. the multipole ansatz for the form factors is used as an example to illustrate all of these findings. | forces within hadrons on the light front |
we report results from searches for anisotropic stochastic gravitational-wave backgrounds using data from the first three observing runs of the advanced ligo and advanced virgo detectors. for the first time, we include virgo data in our analysis and run our search with a new efficient pipeline called pystoch on data folded over one sidereal day. we use gravitational-wave radiometry (broadband and narrow band) to produce sky maps of stochastic gravitational-wave backgrounds and to search for gravitational waves from point sources. a spherical harmonic decomposition method is employed to look for gravitational-wave emission from spatially-extended sources. neither technique found evidence of gravitational-wave signals. hence we derive 95% confidence-level upper limit sky maps on the gravitational-wave energy flux from broadband point sources, ranging from fα ,θ<(0.013 - 7.6 )×10−8 erg cm−2 s−1 hz−1 , and on the (normalized) gravitational-wave energy density spectrum from extended sources, ranging from ωα ,θ<(0.57 - 9.3 )×10−9 sr−1 , depending on direction (θ ) and spectral index (α ). these limits improve upon previous limits by factors of 2.9-3.5. we also set 95% confidence level upper limits on the frequency-dependent strain amplitudes of quasimonochromatic gravitational waves coming from three interesting targets, scorpius x-1, sn 1987a and the galactic center, with best upper limits range from h0<(1.7 - 2.1 )×10-25 , a factor of ≥2.0 improvement compared to previous stochastic radiometer searches. | search for anisotropic gravitational-wave backgrounds using data from advanced ligo and advanced virgo's first three observing runs |
we consider radiation emitted by colour-charged and massive particles crossing strong plane wave backgrounds in gauge theory and gravity. these backgrounds are treated exactly and non-perturbatively throughout. we compute the back-reaction on these fields from the radiation emitted by the probe particles: classically through background-coupled worldline theories, and at tree-level in the quantum theory through three-point amplitudes. consistency of these two methods is established explicitly. we show that the gauge theory and gravity amplitudes are related by the double copy for amplitudes on plane wave backgrounds. finally, we demonstrate that in four-dimensions these calculations can be carried out with a background-dressed version of the massive spinor-helicity formalism. | classical and quantum double copy of back-reaction |
we analyze higgs condensate bubble expansion during a first-order electroweak phase transition in the early universe. the interaction of particles with the bubble wall can be accompanied by the emission of multiple soft gauge bosons. when computed at fixed order in perturbation theory, this process exhibits large logarithmic enhancements which must be resummed to all orders when the wall velocity is large. we perform this resummation both analytically and numerically at leading logarithmic accuracy. the numerical simulation is achieved by means of a particle shower in the broken phase of the electroweak theory. the two approaches agree to the 10% level. for fast-moving walls, we find the scaling of the thermal pressure exerted against the wall to be p~γ2t4, independent of the particle masses, implying a significantly slower terminal velocity than previously suggested. | towards an all-orders calculation of the electroweak bubble wall velocity |
neural networks are a promising technique for parameterizing sub-grid-scale physics (e.g. moist atmospheric convection) in coarse-resolution climate models, but their lack of interpretability and reliability prevents widespread adoption. for instance, it is not fully understood why neural network parameterizations often cause dramatic instability when coupled to atmospheric fluid dynamics. this paper introduces tools for interpreting their behavior that are customized to the parameterization task. first, we assess the nonlinear sensitivity of a neural network to lower-tropospheric stability and the mid-tropospheric moisture, two widely-studied controls of moist convection. second, we couple the linearized response functions of these neural networks to simplified gravity-wave dynamics, and analytically diagnose the corresponding phase speeds, growth rates, wavelengths, and spatial structures. to demonstrate their versatility, these techniques are tested on two sets of neural networks, one trained with a super-parametrized version of the community atmosphere model (spcam) and the second with a near-global cloud-resolving model (gcrm). even though the spcam simulation has a warmer climate than the cloud-resolving model, both neural networks predict stronger heating/drying in moist and unstable environments, which is consistent with observations. moreover, the spectral analysis can predict that instability occurs when gcms are coupled to networks that support gravity waves that are unstable and have phase speeds larger than 5 m/s. in contrast, standing unstable modes do not cause catastrophic instability. using these tools, differences between the spcam- vs. gcrm- trained neural networks are analyzed, and strategies to incrementally improve both of their coupled online performance unveiled. | interpreting and stabilizing machine-learning parametrizations of convection |
the aim of this article is to explore the interplay between the eikonal resummation in impact-parameter space and the exponentiation of infrared divergences in momentum space for gravity amplitudes describing collisions of massive objects. the eikonal governs the classical dynamics relevant to the two-body problem, and its infrared properties are directly linked to the zero-frequency limit of the gravitational wave emission spectrum and to radiation-reaction effects. combining eikonal and infrared exponentiations it is possible to derive these properties at a given loop order starting from lower-loop data. this is illustrated explicitly in n =8 supergravity and in general relativity by deriving the divergent part of the two-loop eikonal from tree-level and one-loop elastic amplitudes. | infrared divergences and the eikonal exponentiation |
we present the miga experiment, an underground long baseline atom interferometer to study gravity at large scale. the hybrid atom-laser antenna will use several atom interferometers simultaneously interrogated by the resonant mode of an optical cavity. the instrument will be a demonstrator for gravitational wave detection in a frequency band (100 mhz-1 hz) not explored by classical ground and space-based observatories, and interesting for potential astrophysical sources. in the initial instrument configuration, standard atom interferometry techniques will be adopted, which will bring to a peak strain sensitivity of 2 ṡ1 0-13/√{h z } at 2 hz. this demonstrator will enable to study the techniques to push further the sensitivity for the future development of gravitational wave detectors based on large scale atom interferometers. the experiment will be realized at the underground facility of the laboratoire souterrain à bas bruit (lsbb) in rustrel-france, an exceptional site located away from major anthropogenic disturbances and showing very low background noise. in the following, we present the measurement principle of an in-cavity atom interferometer, derive the method for gravitational wave signal extraction from the antenna and determine the expected strain sensitivity. we then detail the functioning of the different systems of the antenna and describe the properties of the installation site. | exploring gravity with the miga large scale atom interferometer |
in the presence of self-interactions, the post-inflationary evolution of the inflaton field is driven into the non-linear regime by the resonant growth of its fluctuations. the once spatially homogeneous coherent inflaton is converted into a collection of inflaton particles with non-vanishing momentum. fragmentation significantly alters the energy transfer rate to the inflaton's offspring during the reheating epoch. in this work we introduce a formalism to quantify the effect of fragmentation on particle production rates, and determine the evolution of the inflaton and radiation energy densities, including the corresponding reheating temperatures. for an inflaton potential with a quartic minimum, we find that the efficiency of reheating is drastically diminished after backreaction, yet it can lead to temperatures above the big bang nucleosynthesis limit for sufficiently large couplings. in addition, we use a lattice simulation to estimate the spectrum of induced gravitational waves, sourced by the scalar inhomogeneities, and discuss detectability prospects. we find that a boltzmann approach allows to accurately predict some of the main features of this spectrum. | reheating after inflaton fragmentation |
we present constraints on the tensor-to-scalar ratio r using planck data. we use the latest release of planck maps, processed with the npipe code, which produces calibrated frequency maps in temperature and polarisation for all planck channels from 30 ghz to 857 ghz using the same pipeline. we computed constraints on r using the bb angular power spectrum, and we also discuss constraints coming from the tt spectrum. given planck's noise level, the tt spectrum gives constraints on r that are cosmic-variance limited (with σr = 0.093), but we show that the marginalised posterior peaks towards negative values of r at about the 1.2σ level. we derived planck constraints using the bb power spectrum at both large angular scales (the `reionisation bump') and intermediate angular scales (the `recombination bump') from ℓ = 2 to 150 and find a stronger constraint than that from tt, with σr = 0.069. the planck bb spectrum shows no systematic bias and is compatible with zero, given both the statistical noise and the systematic uncertainties. the likelihood analysis using b modes yields the constraint r < 0.158 at 95% confidence using more than 50% of the sky. this upper limit tightens to r < 0.069 when planck ee, bb, and eb power spectra are combined consistently, and it tightens further to r < 0.056 when the planck tt power spectrum is included in the combination. finally, combining planck with bicep2/keck 2015 data yields an upper limit of r < 0.044. | planck constraints on the tensor-to-scalar ratio |
a novel method for extending the frequency frontier in gravitational wave observations is proposed. it is shown that gravitational waves can excite a magnon. thus, gravitational waves can be probed by a graviton-magnon detector which measures resonance fluorescence of magnons. searching for gravitational waves with a wave length λ by using a ferromagnetic sample with a dimension l, the sensitivity of the graviton-magnon detector reaches spectral densities, around 5.4 ×10-22×(l/λ/2 π ) -2[hz-1 /2] at 14 ghz and 8.6 ×10-21×(l/λ/2 π ) -2[hz-1 /2] at 8.2 ghz, respectively. | probing ghz gravitational waves with graviton-magnon resonance |
the scalar perturbation induced gravitational waves are a probe of the primordial density perturbation spectrum on small scales. in this paper, we show that they can also probe the thermal history of the universe. we assume the universe underwent a stage with a constant equation of state parameter w, followed by the radiation-dominated stage of the conventional big bang universe. we find that the infrared slope of the power spectrum of the induced stochastic gravitational wave background for decelerating cosmologies is related to the equation of state of the universe. furthermore, the induced gravitational wave spectrum has in general a broken power-law shape around the scale of reheating. interestingly, below the threshold 0w= of the equation of state parameter, the broken power-law presents a peak for a dirac delta peak in the scalar spectrum. for a finite width peak, the threshold changes to w=-1/15 depending on the value of the width. in some cases, such a broken power-law gravitational wave spectrum may degenerate to the spectrum from other sources like phase transitions or global cosmic strings. | induced gravitational waves as a probe of thermal history of the universe |
in this white paper, we discuss the prospects for characterizing and identifying dark matter using gravitational waves, covering a wide range of dark matter candidate types and signals. we argue that present and upcoming gravitational wave probes offer unprecedented opportunities for unraveling the nature of dark matter and we identify the most urgent challenges and open problems with the aim of encouraging a strong community effort at the interface between these two exciting fields of research. | gravitational wave probes of dark matter: challenges and opportunities |
the assumptions of large-scale homogeneity and isotropy underly the familiar friedmann-lemaître-robertson-walker (flrw) metric that appears to be an accurate description of our universe. in this paper, we propose a new strategy of testing the validity of the flrw metric, based on the galactic-scale lensing systems where strongly lensed gravitational waves and their electromagnetic counterparts can be simultaneously detected. each strong lensing system creates opportunity to infer the curvature parameter of the universe. consequently, combined analysis of many such systems will provide a model-independent tool to test the validity of the flrw metric. our study demonstrates that the third-generation ground based gw detectors, like the einstein telescope (et) and space-based detectors, like the big bang observer (bbo), are promising concerning determination of the curvature parameter or possible detection of deviation from the flrw metric. such accurate measurements of the flrw metric can become a milestone in precision gw cosmology. | direct test of the flrw metric from strongly lensed gravitational wave observations |
we show that gravitational wave detectors based on a type of atom interferometry are sensitive to ultralight scalar dark matter. such dark matter can cause temporal oscillations in fundamental constants with a frequency set by the dark matter mass and amplitude determined by the local dark matter density. the result is a modulation of atomic transition energies. we point out a new time-domain signature of this effect in a type of gravitational wave detector that compares two spatially separated atom interferometers referenced by a common laser. such a detector can improve on current searches for electron-mass or electric-charge modulus dark matter by up to 10 orders of magnitude in coupling, in a frequency band complementary to that of other proposals. it demonstrates that this class of atomic sensors is qualitatively different from other gravitational wave detectors, including those based on laser interferometry. by using atomic-clock-like interferometers, laser noise is mitigated with only a single baseline. these atomic sensors can thus detect scalar signals in addition to tensor signals. | search for light scalar dark matter with atomic gravitational wave detectors |
in this paper, the generalized jacobi elliptical functional (jef) and modified khater (mk) methods are employed to find the soliton, breather, kink, periodic kink, and lump wave solutions of the ostrovsky equation. this model is considered as a mathematical modification model of the korteweg-de vries (kdv) equation with respect to the effects of background rotation. the solitary solutions of the well-known mathematical model (kdv equation) usually decay and are replaced by radiating inertia gravity waves. the obtained solitary solutions emerge the localized wave packet as a persistent and dominant feature. many distinct solutions are obtained through the employed computational schemes. moreover, some solutions are sketched in 2d, 3d, and contour plots. the effective and powerful of the two used computational schemes are tested. furthermore, the accuracy of the obtained solutions is examined through a comparison between them and that had been obtained in previously published research. | diverse solitary and jacobian solutions in a continually laminated fluid with respect to shear flows through the ostrovsky equation |
axionlike particles (alps) are a compelling candidate for dark matter (dm), whose production is associated with the formation of a string-wall network. if walls bounded by strings persist, which requires the potential to have multiple local minima (n >1 ), they must annihilate before they become dominant. they annihilate mostly into gravitational waves and nonrelativistic alps. we show that for alps other than the qcd axion these gravitational waves, if produced at temperatures below 100 ev, could be detected by future cosmological probes for alps with mass from 10-16 to 106 ev that could constitute the entirety of the dm. | gravitational waves from axionlike particle cosmic string-wall networks |
we perform a global fit of the extended scalar singlet model with a fermionic dark matter (dm) candidate. using the most up-to-date results from the planck measured dm relic density, direct detection limits from the xenon1t (2018) experiment, electroweak precision observables and higgs searches at colliders, we constrain the 7-dimensional model parameter space. we also find regions in the model parameter space where a successful electroweak baryogenesis (ewbg) can be viable. this allows us to compute the gravitational wave (gw) signals arising from the phase transition, and discuss the potential discovery prospects of the model at current and future gw experiments. our global fit places a strong upper and lower limit on the second scalar mass, the fermion dm mass and the scalar-fermion dm coupling. in agreement with previous studies, we find that our model can simultaneously yield a strong first-order phase transition and saturate the observed dm abundance. more importantly, the gw spectra of viable points can often be within reach of future gw experiments such as lisa, decigo and bbo. | gravitational waves and electroweak baryogenesis in a global study of the extended scalar singlet model |
wave control is usually performed by spatially engineering the properties of a medium. because time and space play similar roles in wave propagation, manipulating time boundaries provides a complementary approach. here, we experimentally demonstrate the relevance of this concept by introducing instantaneous time mirrors. we show with water waves that a sudden change of the effective gravity generates time-reversed waves that refocus at the source. we generalize this concept for all kinds of waves, introducing a universal framework which explains the effect of any time disruption on wave propagation. we show that sudden changes of the medium properties generate instant wave sources that emerge instantaneously from the entire space at the time disruption. the time-reversed waves originate from these `cauchy sources’, which are the counterpart of huygens virtual sources on a time boundary. it allows us to revisit the holographic method and introduce a new approach for wave control. | time reversal and holography with spacetime transformations |
gravitational wave observations of compact binaries allow us to test general relativity (and modifications thereof) in the strong and highly dynamical field regime of gravity. here, we confront two extensions to general relativity, dynamical chern-simons, and einstein-dilaton-gauss-bonnet theories, against the gravitational wave sources from the gwtc-1 and gwtc-2 catalogs by the ligo-virgo collaboration. by stacking the posterior of individual events, we strengthen the constraint on the square root of the coupling parameter in einstein-dilaton-gauss-bonnet gravity to √{αedgb }<1.7 km , but we are unable to place meaningful constraints on dynamical chern-simons gravity. importantly, we also show that our bounds are robust to (i) the choice of general-relativity base waveform model, upon which we add modifications, (ii) unknown higher post-newtonian order terms in the modifications to general relativity, (iii) the small-coupling approximation, and (iv) uncertainties on the nature of the constituent compact objects. | improved gravitational-wave constraints on higher-order curvature theories of gravity |
we present a novel baryogenesis mechanism in which the asymmetry is sourced from heavy particles which either gain their mass or are created during bubble expansion in a strong first order phase transition. these particles then decay in a c p and baryon number violating way inside the bubble. the particles are inherently out of equilibrium and sufficiently dilute after wall crossing so the third sakharov condition is easily met. washout is avoided provided the reheat temperature is sufficiently below the scale of the heavy particles. the mechanism relies on moderate supercooling and relativistic walls which—in contrast to electroweak baryogenesis—generically leads to a sizable gravitational wave signal, although in the simplest realizations at frequencies beyond upcoming detectors. we present a simple example model and discuss the restrictions on the parameter space for the mechanism to be successful. we find that high reheat temperatures trh≳1010 gev are generally preferred, whereas stronger supercooling allows for temperatures as low as trh∼106 gev , provided the vacuum energy density is sufficiently suppressed. we briefly comment on using resonantly enhanced c p violation to achieve even lower scales. | baryogenesis via relativistic bubble expansion |
mineral dust is an important component of the climate system, interacting with radiation, clouds, and biogeochemical systems and impacting atmospheric circulation, air quality, aviation, and solar energy generation. these impacts are sensitive to dust particle size distribution (psd), yet models struggle or even fail to represent coarse (diameter (d) >2.5 µm) and giant (d>20 µm) dust particles and the evolution of the psd with transport. here we examine three state-of-the-art airborne observational datasets, all of which measured the full size range of dust (d=0.1 to >100 µm) at different stages during transport with consistent instrumentation. we quantify the presence and evolution of coarse and giant particles and their contribution to optical properties using airborne observations over the sahara (from the fennec field campaign) and in the saharan air layer (sal) over the tropical eastern atlantic (from the aer-d field campaign). observations show significantly more abundant coarse and giant dust particles over the sahara compared to the sal: effective diameters of up to 20 µm were observed over the sahara compared to 4 µm in the sal. excluding giant particles over the sahara results in significant underestimation of mass concentration (40 %), as well as underestimates of both shortwave and longwave extinction (18 % and 26 %, respectively, from scattering calculations), while the effects in the sal are smaller but non-negligible. the larger impact on longwave extinction compared to shortwave implies a bias towards a radiative cooling effect in dust models, which typically exclude giant particles and underestimate coarse-mode concentrations. a compilation of the new and published effective diameters against dust age since uplift time suggests that two regimes of dust transport exist. during the initial 1.5 d, both coarse and giant particles are rapidly deposited. during the subsequent 1.5 to 10 d, psd barely changes with transport, and the coarse mode is retained to a much greater degree than expected from estimates of gravitational sedimentation alone. the reasons for this are unclear and warrant further investigation in order to improve dust transport schemes and the associated radiative effects of coarse and giant particles in models. | coarse and giant particles are ubiquitous in saharan dust export regions and are radiatively significant over the sahara |
we propose a new model-independent measurement strategy for the propagation speed of gravitational waves (gws) based on strongly lensed gws and their electromagnetic (em) counterparts. this can be done in two ways: by comparing arrival times of gws and their em counterparts and by comparing the time delays between images seen in gws and their em counterparts. the lensed gw-em event is perhaps the best way to identify an em counterpart. conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. its differential setting (i.e., measuring the difference between time delays in gw and em domains) makes it robust against lens modeling details (photons and gws travel in the same lensing potential) and against internal time delays between gw and em emission acts. it requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. we expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed gw events would be observed each year. the power of this method is mainly limited by the timing accuracy of the em counterpart, which for kilonovae is around 1 04 s . this uncertainty can be suppressed by a factor of ∼1 010, if strongly lensed transients of much shorter duration associated with the gw event can be identified. candidates for such short transients include short γ -ray bursts and fast radio bursts. | speed of gravitational waves from strongly lensed gravitational waves and electromagnetic signals |
understanding the noise in gravitational-wave detectors is central to detecting and interpreting gravitational-wave signals. glitches are transient, non-gaussian noise features that can have a range of environmental and instrumental origins. the gravity spy project uses a machine-learning algorithm to classify glitches based upon their time-frequency morphology. the resulting set of classified glitches can be used as input to detector-characterisation investigations of how to mitigate glitches, or data-analysis studies of how to ameliorate the impact of glitches. here we present the results of the gravity spy analysis of data up to the end of the third observing run of advanced laser interferometric gravitational-wave observatory (ligo). we classify 233981 glitches from ligo hanford and 379805 glitches from ligo livingston into morphological classes. we find that the distribution of glitches differs between the two ligo sites. this highlights the potential need for studies of data quality to be individually tailored to each gravitational-wave observatory. | data quality up to the third observing run of advanced ligo: gravity spy glitch classifications |
we examine the characteristics of secondary gravity waves (gws) excited by a localized (in space) and intermittent (in time) body force in the atmosphere. this force is a horizontal acceleration of the background flow created when primary gws dissipate and deposit their momentum on spatial and temporal scales of the wave packet. a broad spectrum of secondary gws is excited with horizontal scales much larger than that of the primary gw. the polarization relations cause the temperature spectrum of the secondary gws generally to peak at larger intrinsic periods τir and horizontal wavelengths λh than the vertical velocity spectrum. we find that the one-dimensional spectra (with regard to frequency or wave number) follow lognormal distributions. we show that secondary gws can be identified by a horizontally displaced observer as "fishbone" or ">" structures in z − t plots whereby the positive and negative gw phase lines meet at the "knee," zknee, which is the altitude of the force center. we present two wintertime cases of lidar temperature measurements at mcmurdo, antarctica (166.69°e, 77.84°s) whereby fishbone structures are seen with zknee=43 and 52 km. we determine the gw parameters and density-weighted amplitudes for each. we show that these parameters are similar below and above zknee. we verify that the gws with upward (downward) phase progression are downward (upward) propagating via use of model background winds. we conclude that these gws are likely secondary gws having ground-based periods τr=6-10 hr and vertical wavelengths λz=6-14 km, and that they likely propagate primarily southward. | the excitation of secondary gravity waves from local body forces: theory and observation |
we study the gravitational-wave (gw) signature of first-order chiral phase transitions (χ pts ) in strongly interacting hidden or dark sectors. we do so using several effective models in order to reliably capture the relevant nonperturbative dynamics. this approach allows us to explicitly calculate key quantities characterizing the χ pt without having to resort to rough estimates. most importantly, we find that the transition's inverse duration β normalized to the hubble parameter h is at least 2 orders of magnitude larger than typically assumed in comparable scenarios, namely, β /h ≳o (1 04 ) . the obtained gw spectra then suggest that signals from hidden χ pts occurring at around 100 mev might be in reach of lisa, while decigo and bbo may detect a stochastic gw background associated with transitions between roughly 1 gev and 10 tev. signatures of transitions at higher temperatures are found to be outside the range of any currently proposed experiment. even though predictions from different effective models are qualitatively similar, we find that they may vary considerably from a quantitative point of view, which highlights the need for true first-principle calculations such as lattice simulations. | observational prospects for gravitational waves from hidden or dark chiral phase transitions |
we report the first realization of large momentum transfer (lmt) clock atom interferometry. using single-photon interactions on the strontium 1s0-3p1 transition, we demonstrate mach-zehnder interferometers with state-of-the-art momentum separation of up to 141 ℏ k and gradiometers of up to 81 ℏ k . moreover, we circumvent excited state decay limitations and extend the gradiometer duration to 50 times the excited state lifetime. because of the broad velocity acceptance of the interferometry pulses, all experiments are performed with laser-cooled atoms at a temperature of 3 μ k . this work has applications in high-precision inertial sensing and paves the way for lmt-enhanced clock atom interferometry on even narrower transitions, a key ingredient in proposals for gravitational wave detection and dark matter searches. | large momentum transfer clock atom interferometry on the 689 nm intercombination line of strontium |
equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. this is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. in this situation, much lower level secondary noises then set the overall performance. if, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers), the laser noise experiences different delays in the two arms and will hence not directly cancel at the photo detector. to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. it relies on properly time-shifting and linearly combining independent doppler measurements, and for this reason it has been called time-delay interferometry (tdi). this article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of tdi. although emphasis on the application of tdi to the laser interferometer space antenna mission appears throughout this article, tdi can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. we have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the tdi data combinations. | time-delay interferometry |
the arrival of gravitational wave astronomy and a growing number of time-domain focused observatories are set to lead to a increasing number of detections of short gamma-ray bursts (grbs) launched with a moderate inclination to earth. being nearby events, these are also prime candidates for very long-term follow-up campaigns and very-long-baseline interferometry (vlbi), which has implications for multi-messenger modelling, data analysis, and statistical inference methods applied to these sources. here we present a comprehensive modelling update that directly incorporates into afterglowpy astrometric observations of the grb position, poissonian statistics for faint sources, and modelling of a trans-relativistic population of electrons. we use the revolutionary event gw170817 to demonstrate the impact of these extensions both for the best-fit physics parameters and model selection methods that assess the statistical significance of additional late-time emission components. by including in our analysis the latest chandra x-ray observations of grb 170817a, we find only weak evidence (less than two sigma) for a new emission component at late times, which makes for a slightly more natural fit to the centroid evolution and prediction for the external medium density. | modelling of long-term afterglow counterparts to gravitational wave events: the full view of grb 170817a |
the observed pattern of fermion masses and mixing is an outstanding puzzle in particle physics, generally known as the flavor problem. over the years, guided by precision neutrino oscillation data, discrete flavor symmetries have often been used to explain the neutrino mixing parameters, which look very different from the quark sector. in this review, we discuss the application of non-abelian finite groups to the theory of neutrino masses and mixing in the light of current and future neutrino oscillation data. we start with an overview of the neutrino mixing parameters, comparing different global fit results and limits on normal and inverted neutrino mass ordering schemes. then, we discuss a general framework for implementing discrete family symmetries to explain neutrino masses and mixing. we discuss cp violation effects, giving an update of cp predictions for trimaximal models with nonzero reactor mixing angle and models with partial $\mu-\tau$ reflection symmetry, and constraining models with neutrino mass sum rules. the connection between texture zeroes and discrete symmetries is also discussed. we summarize viable higher-order groups, which can explain the observed pattern of lepton mixing where the non-zero $\theta_{13}$ plays an important role. we also review the prospects of embedding finite discrete symmetries in the grand unified theories and with extended higgs fields. models based on modular symmetry are also briefly discussed. a major part of the review is dedicated to the phenomenology of flavor symmetries and possible signatures in the current and future experiments at the intensity, energy, and cosmic frontiers. in this context, we discuss flavor symmetry implications for neutrinoless double beta decay, collider signals, leptogenesis, dark matter, as well as gravitational waves. | phenomenology of lepton masses and mixing with discrete flavor symmetries |
this document presents a summary of the 2023 terrestrial very-long-baseline atom interferometry workshop hosted by cern. the workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (ai) prototypes and their potential for detecting ultralight dark matter and gravitational waves. the primary objective of the workshop was to lay the groundwork for an international tvlbai proto-collaboration. this collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale ai projects. the ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. the key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions. | terrestrial very-long-baseline atom interferometry: workshop summary |
we investigate the sensitivity of the laser interferometer space antenna (lisa) to the anisotropies of the stochastic gravitational wave background (sgwb). we first discuss the main astrophysical and cosmological sources of sgwb which are characterized by anisotropies in the gw energy density, and we build a signal-to-noise estimator to quantify the sensitivity of lisa to different multipoles. we then perform a fisher matrix analysis of the prospects of detectability of anisotropic features with lisa for individual multipoles, focusing on a sgwb with a power-law frequency profile. we compute the noise angular spectrum taking into account the specific scan strategy of the lisa detector. we analyze the case of the kinematic dipole and quadrupole generated by doppler boosting an isotropic sgwb. we find that β ωgw ~ 2 × 10-11 is required to observe a dipolar signal with lisa. the detector response to the quadrupole has a factor ~ 103 β relative to that of the dipole. the characterization of the anisotropies, both from a theoretical perspective and from a map-making point of view, allows us to extract information that can be used to understand the origin of the sgwb, and to discriminate among distinct superimposed sgwb sources. | probing anisotropies of the stochastic gravitational wave background with lisa |
we study the formation and evolution of domain walls with initial inflationary fluctuations by numerical lattice calculations that, for the first time, correctly take into account correlations on superhorizon scales. we find that, contrary to the widely-held claim over the past few tens of years, the domain wall network exhibits remarkable stability even when the initial distribution is largely biased toward one of the minima. this is due to the fact that the domain wall network retains information about initial conditions on superhorizon scales, and that the scaling solution is not a local attractor in this sense. our finding immediately implies that such domain walls will have a significant impact on cosmology, including the production of gravitational waves, baryogenesis, and dark matter from domain walls. applying this result to the axion-like particle domain wall, we show that it not only explains the isotropic cosmic birefringence suggested by the recent analysis, but also predicts anisotropic cosmic birefringence that is nearly scale-invariant on large scales and can be probed by future cmb observations. | stability of domain wall network with initial inflationary fluctuations and its implications for cosmic birefringence |
we study the spectrum of gravitational waves produced by a first order phase transition in a hidden sector that is colder than the visible sector. in this scenario, bubbles of the hidden sector vacuum can be nucleated through either thermal fluctuations or quantum tunnelling. if a cold hidden sector undergoes a thermally induced transition, the amplitude of the gravitational wave signal produced will be suppressed and its peak frequency shifted compared to if the hidden and visible sector temperatures were equal. this could lead to signals in a frequency range that would otherwise be ruled out by constraints from big bang nucleosynthesis. alternatively, a sufficiently cold hidden sector could fail to undergo a thermal transition and subsequently transition through the nucleation of bubbles by quantum tunnelling. in this case the bubble walls might accelerate with completely negligible friction. the resulting gravitational wave spectrum has a characteristic frequency dependence, which may allow such cold hidden sectors to be distinguished from models in which the hidden and visible sector temperatures are similar. we compare our results to the sensitivity of the future gravitational wave experimental programme. | hearing without seeing: gravitational waves from hot and cold hidden sectors |
gravity waves are one of the main drivers of atmospheric dynamics. the spatial resolution of most global atmospheric models, however, is too coarse to properly resolve the small scales of gravity waves, which range from tens to a few thousand kilometers horizontally, and from below 1 km to tens of kilometers vertically. gravity wave source processes involve even smaller scales. therefore, general circulation models (gcms) and chemistry climate models (ccms) usually parametrize the effect of gravity waves on the global circulation. these parametrizations are very simplified. for this reason, comparisons with global observations of gravity waves are needed for an improvement of parametrizations and an alleviation of model biases. we present a gravity wave climatology based on atmospheric infrared limb emissions observed by satellite (gracile). gracile is a global data set of gravity wave distributions observed in the stratosphere and the mesosphere by the infrared limb sounding satellite instruments high resolution dynamics limb sounder (hirdls) and sounding of the atmosphere using broadband emission radiometry (saber). typical distributions (zonal averages and global maps) of gravity wave vertical wavelengths and along-track horizontal wavenumbers are provided, as well as gravity wave temperature variances, potential energies and absolute momentum fluxes. this global data set captures the typical seasonal variations of these parameters, as well as their spatial variations. the gracile data set is suitable for scientific studies, and it can serve for comparison with other instruments (ground-based, airborne, or other satellite instruments) and for comparison with gravity wave distributions, both resolved and parametrized, in gcms and ccms. the gracile data set is available as supplementary data at https://doi.org/10.1594/pangaea.879658. | gracile: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings |
kagra is a newly built gravitational wave observatory, a laser interferometer with a 3 km arm length, located at kamioka, gifu, japan. in this series of articles we present an overview of the baseline kagra, for which we finished installing the designed configuration in 2019. this article describes the method of calibration (cal) used for reconstructing gravitational wave signals from the detector outputs, as well as the characterization of the detector (det). we also review the physical environmental monitoring (pem) system and the geophysics interferometer (gif). both are used for characterizing and evaluating the data quality of the gravitational wave channel. they play important roles in utilizing the detector output for gravitational wave searches. these characterization investigations will be even more important in the near future, once gravitational wave detection has been achieved, and in using kagra in the gravitational wave astronomy era. | overview of kagra: calibration, detector characterization, physical environmental monitors, and the geophysics interferometer |
inspired by the recent determination of the w -boson mass by the cdf collaboration, we revisit an s o (10 ) axion model in which a scalar s u (2 )l triplet field with zero hypercharge is known to acquire a nonzero vacuum expectation value (vev) through its mixing with the standard model higgs doublet. the triplet vev provides a sizable contribution to the w mass, which helps in significantly lowering the 7 σ discrepancy between the standard model prediction and the higher cdf value for mw. we show that the relatively light triplet mass (∼(1 - 50 ) tev ) is compatible with gauge coupling unification and observable proton decay. an unbroken z2 gauge symmetry, coupled with the presence of two fermionic 10-plets required to resolve the axion domain wall problem means that both axions and a stable intermediate mass (∼109- 1010 gev ) fermion are plausible dark matter candidates. we also display the gravitational wave spectrum from the intermediate scale topologically stable cosmic strings predicted by the model. | heavier w boson, dark matter, and gravitational waves from strings in an so(10) axion model |
we outline laser interferometer measurements to search for variation of the electromagnetic fine-structure constant α and particle masses (including a nonzero photon mass). we propose a strontium optical lattice clock—silicon single-crystal cavity interferometer as a small-scale platform for these measurements. our proposed laser interferometer measurements, which may also be performed with large-scale gravitational-wave detectors, such as ligo, virgo, geo600, or tama300, may be implemented as an extremely precise tool in the direct detection of scalar dark matter that forms an oscillating classical field or topological defects. | enhanced effects of variation of the fundamental constants in laser interferometers and application to dark-matter detection |
high frequency gravitational waves can be detected by observing the frequency modulation they impart on photons. we discuss fundamental limitations to this method related to the fact that it is impossible to construct a perfectly rigid detector. we then propose several novel methods to search for o (mhz -ghz ) gravitational waves based on the frequency modulation induced in the spectrum of an intense laser beam, by applying optical frequency demodulation techniques, or by using optical atomic clock technology. we find promising sensitivities across a broad frequency range. | high-frequency gravitational wave detection via optical frequency modulation |
we study the nature of the electroweak phase transition (ewpt) in models where the higgs boson emerges as a pseudo-nambu-goldstone boson of an approximate global symmetry of a new strongly interacting sector confining around the tev scale. our analysis focuses for the first time on the case where the ewpt is accompanied by the confinement phase transition of the strong sector. we describe the confinement in terms of the dilaton, the pseudo-nambu-goldstone boson of spontaneously broken conformal invariance of the strong sector. the dilaton can either be a mesonlike or a glueball-like state and we demonstrate a significant qualitative difference in their dynamics. we show that the ewpt can naturally be strongly first order, due to the nearly conformal nature of the dilaton potential. furthermore, we examine the sizable scale variation of the higgs potential parameters during the ewpt. in particular, we consider in detail the case of a varying top quark yukawa coupling, and show that the resulting c p violation is sufficient for successful electroweak baryogenesis. we demonstrate that this source of c p violation is compatible with existing flavor and c p constraints. our scenario can be tested in complementary ways: by measuring the c p -odd top yukawa coupling in electron electric dipole moment experiments, by searching for dilaton production and deviations in higgs couplings at colliders, and through gravitational waves at lisa. | baryon asymmetry from a composite higgs boson |
gravitational waves (gws) generate oscillating electromagnetic effects in the vicinity of external electric and magnetic fields. we discuss this phenomenon with a particular focus on reinterpreting the results of axion haloscopes based on lumped-element detectors, which probe gws in the 100 khz-100 mhz range. measurements from abracadabra and shaft already place bounds on gws, although the present strain sensitivity is weak. however, we demonstrate that the sensitivity scaling with the volume of such instruments is significant—faster than for axions—and so rapid progress will be made in the future. with no modifications, dmradio-m3 will have a gw strain sensitivity of h ∼10-20 at 200 mhz. a simple modification of the pickup loop used to readout the induced magnetic flux can parametrically enhance the gw sensitivity, particularly at lower frequencies. | novel search for high-frequency gravitational waves with low-mass axion haloscopes |
we give an account of the gravitational memory effect in the presence of the exact plane wave solution of einstein's vacuum equations. this allows an elementary but exact description of the soft gravitons and how their presence may be detected by observing the motion of freely falling particles. the theorem of bondi and pirani on caustics (for which we present a new proof) implies that the asymptotic relative velocity is constant but not zero, in contradiction with the permanent displacement claimed by zel'dovich and polnarev. a non-vanishing asymptotic relative velocity might be used to detect gravitational waves through the "velocity memory effect", considered by braginsky, thorne, grishchuk, and polnarev. | the memory effect for plane gravitational waves |
we identify a characteristic pattern in the scalar-induced stochastic gravitational wave background from particle production during inflation. if particle production is sufficiently efficient, the scalar power spectrum exhibits $\mathcal{o}(1)$ oscillations periodic in $k$, characteristic of a sharp feature, with an exponentially enhanced envelope. we systematically study the properties of the induced spectrum of gravitational waves sourced after inflation and find that this inherits the periodic structure in $k$, resulting in a peak in the gravitational wave energy density spectrum with $\mathcal{o}(10 \%)$ modulations. the frequency of the oscillation in the scalar power spectrum is determined by the scale of the feature during inflation and in turn sets the frequency of modulations in the gravitational wave signal. we present an explicit realisation of this phenomenon in the framework of multifield inflation, in the form of a strong sharp turn in the inflationary trajectory. the resulting stochastic background is potentially detectable in future gravitational wave observatories, and considerations of backreaction and perturbativity can be used to constrain the parameter space from the theoretical side. our work motivates more extensive research linking primordial features to observable properties of the stochastic background of gravitational waves, and dedicated development in data analysis for their detection. | oscillations in the stochastic gravitational wave background from sharp features and particle production during inflation |
non-invertible global symmetry often predicts degeneracy in axion potentials and carries important information about the global form of the gauge group. when these symmetries are spontaneously broken they can lead to the formation of stable axion domain wall networks which support topological degrees of freedom on their worldvolume. such non-invertible symmetries can be broken by embedding into appropriate larger uv gauge groups where small instanton contributions lift the vacuum degeneracy, and provide a possible solution to the domain wall problem. we explain these ideas in simple illustrative examples and then apply them to the standard model, whose gauge algebra and matter content are consistent with several possible global structures. each possible global structure leads to different selection rules on the axion couplings, and various uv completions of the standard model lead to more specific relations. as a proof of principle, we also present an example of a uv embedding of the standard model which can solve the axion domain wall problem. the formation and annihilation of the long-lived axion domain walls can lead to observables, such as gravitational wave signals. observing such signals, in combination with the axion coupling measurements, can provide valuable insight into the global structure of the standard model, as well as its uv completion. | axion domain walls, small instantons, and non-invertible symmetry breaking |
whitham and benjamin predicted in 1967 that small-amplitude periodic traveling stokes waves of the 2d-gravity water waves equations are linearly unstable with respect to long-wave perturbations, if the depth h is larger than a critical threshold hwb≈1.363 . in this paper, we completely describe, for any finite value of h >0 , the four eigenvalues close to zero of the linearized equations at the stokes wave, as the floquet exponent μ is turned on. we prove, in particular, the existence of a unique depth hwb, which coincides with the one predicted by whitham and benjamin, such that, for any 0 <h <hwb , the eigenvalues close to zero are purely imaginary and, for any h >hwb , a pair of non-purely imaginary eigenvalues depicts a closed figure "8", parameterized by the floquet exponent. as h →hwb+ the "8" collapses to the origin of the complex plane. the complete bifurcation diagram of the spectrum is not deduced as in deep water, since the limits h →+∞ (deep water) and μ →0 (long waves) do not commute. in finite depth, the four eigenvalues have all the same size o (μ ) , unlike in deep water, and the analysis of their splitting is much more delicate, requiring, as a new ingredient, a non-perturbative step of block-diagonalization. along the whole proof, the explicit dependence of the matrix entries with respect to the depth h is carefully tracked. | benjamin-feir instability of stokes waves in finite depth |
we distinguish between the notions of asymptotic causality and infrared causality for gravitational effective field theories, and show that the latter gives constraints consistent with gravitational positivity bounds. we re-explore the scattering of gravitational waves in a spherically symmetric background in the eft of gravity in d ≥ 5, for which the leading-order correction to einstein gravity is determined by the gauss-bonnet operator. we reproduce the known result that the truncated effective theory exhibits apparent time advances relative to the background geometry for specific polarisations, which naively signal a violation of causality. we show that by properly identifying the regime of validity of the effective theory, the apparent time advance can be shown to be unresolvable. to illustrate this, we identify specific higher-dimension operators in the eft expansion which become large for potentially resolvable time advances, rendering the eft expansion invalid. our results demonstrate how staying within the confines of the eft, neither infrared nor asymptotic causality are ever violated for einstein-gauss-bonnet gravity, no matter how low the scale, and furthermore its causality can be understood without appealing to a precise uv completion such as string theory. | a cautionary case of casual causality |
we study under which conditions a first-order phase transition in a composite dark sector can yield an observable stochastic gravitational-wave signal. to this end, we employ the linear-sigma model featuring $n_f=3,4,5$ flavours and perform a cornwall-jackiw-tomboulis computation also accounting for the effects of the polyakov loop. the model allows us to investigate the chiral phase transition in regimes that can mimic qcd-like theories incorporating in addition composite dynamics associated with the effects of confinement-deconfinement phase transition. a further benefit of this approach is that it allows to study the limit in which the effective interactions are weak. we show that strong first-order phase transitions occur for weak effective couplings of the composite sector leading to gravitational-wave signals potentially detectable at future experimental facilities. | gravitational waves from composite dark sectors |
first order phase transitions could play a major role in the early universe, providing important phenomenological consequences, such as the production of gravitational waves and the generation of baryon asymmetry. an important aspect that determines the properties of the phase transition is the dynamics of the true-vacuum bubbles, which is controlled by the density perturbations in the hot plasma. we study this aspect presenting, for the first time, the full solution of the linearized boltzmann equation for the top quark species coupled to the higgs field during a first-order electroweak phase transition. our approach, differently from the traditional one based on the fluid approximation, does not rely on any ansatz and can fully capture the density perturbations in the plasma. we find that our results significantly differ from the ones obtained in the fluid approximation (including its extensions and modifications), both at the qualitative and quantitative level. in particular sizable differences are found for the friction acting on the bubble wall. | bubble wall dynamics at the electroweak phase transition |
primordial non-gaussianity encodes vital information of the physics of the early universe, particularly during the inflationary epoch. to explore the local-type primordial non-gaussianity f nl, we study the anisotropies in gravitational wave background induced by the linear cosmological scalar perturbations during radiation domination in the early universe. we provide the first complete analysis to the angular power spectrum of such scalar-induced gravitational waves. the spectrum is expressed in terms of the initial inhomogeneities, the sachs-wolfe effect, and their crossing. it is anticipated to have frequency dependence and multipole dependence, i.e., cℓ (ν) ∝ [ℓ(ℓ+1)]-1 with ν being a frequency and ℓ referring to the ℓ-th spherical harmonic multipole. in particular, the initial inhomogeneites in this background depend on gravitational-wave frequency. these properties are potentially useful for the component separation, foreground removal, and breaking degeneracies in model parameters, making the non-gaussian parameter f nl measurable. further, theoretical expectations may be tested by space-borne gravitational-wave detectors in future. | primordial non-gaussianity f nl and anisotropies in scalar-induced gravitational waves |
tidal currents and large-scale oceanic currents are known to modify ocean wave properties, causing extreme sea states that are a hazard to navigation. recent advances in the understanding and modeling capability of open ocean currents have revealed the ubiquitous presence of eddies, fronts, and filaments at scales 10-100 km. based on realistic numerical models, we show that these structures can be the main source of variability in significant wave heights at scales less than 200 km, including important variations down to 10 km. model results are consistent with wave height variations along satellite altimeter tracks, resolved at scales larger than 50 km. the spectrum of significant wave heights is found to be of the order of 70><hs>>2/>(g2><tm0,-1>>2>) times the current spectrum, where ><hs>> is the spatially averaged significant wave height, ><tm0,-1>> is the energy-averaged period, and g is the gravity acceleration. this variability induced by currents has been largely overlooked in spite of its relevance for extreme wave heights and remote sensing.<abstract type="synopsis"><title type="main">plain language summarywe show that the variations in currents at scales 10 to 100 km are the main source of variations in wave heights at the same scales. our work uses a combination of realistic numerical models for currents and waves and data from the jason-3 and saral/altika satellites. this finding will be of interest for the investigation of extreme wave heights, remote sensing, and air-sea interactions. as an immediate application, the present results will help constrain the error budget of the up-coming satellite missions, in particular the surface water and ocean topography (swot) mission, and decide how the data will have to be processed to arrive at accurate sea level and wave measurements. it will also help in the analysis of wave measurements by the cfosat satellite. | small-scale open ocean currents have large effects on wind wave heights |
binary neutron star mergers observations are a unique way to constrain fundamental physics and astrophysics at the extreme. the interpretation of gravitational-wave events and their electromagnetic counterparts crucially relies on general-relativistic models of the merger remnants. quantitative models can be obtained only by means of numerical relativity simulations in 3 +1 dimensions including detailed input physics for the nuclear matter, electromagnetic and weak interactions. this review summarizes the current understanding of merger remnants focusing on some of the aspects that are relevant for multimessenger observations. | neutron star merger remnants |
in a vacuum first-order phase transition, gravitational waves are generated from collision of bubbles of the true vacuum. the spectrum from such collisions takes the form of a broken power law. we consider a toy model for such a phase transition, where the dynamics of the scalar field depends on a single parameter λ ¯, which controls how thin the bubble wall is at nucleation and how close to degenerate the vacua are relative to the barrier. we extend on our previous work by performing a series of simulations with a range of λ ¯. the peak of the gravitational-wave power spectrum varies by up to a factor of 1.3, which is probably an unobservable effect. we find that the uv power law in the gravitational-wave spectrum becomes steeper as λ ¯→0 , varying between k-1.4 and k-2.2 for the λ ¯ considered. this provides some evidence that the form of the underlying effective potential of a vacuum first-order phase transition could be determined from the gravitational-wave spectrum it produces. | gravitational waves from vacuum first-order phase transitions. ii. from thin to thick walls |
the three advanced virgo and ligo gravitational wave detectors participated to the third observing run (o3) between 1 april 2019 15:00 utc and 27 march 2020 17:00 utc, leading to several gravitational wave detections per month. this paper describes the advanced virgo detector calibration and the reconstruction of the detector strain h(t) during o3, as well as the estimation of the associated uncertainties. for the first time, the photon calibration technique as been used as reference for virgo calibration, which allowed to cross-calibrate the strain amplitude of the virgo and ligo detectors. the previous reference, so-called free swinging michelson technique, has still been used but as an independent cross-check. h(t) reconstruction and noise subtraction were processed online, with good enough quality to prevent the need for offline reprocessing, except for the two last weeks of september 2019. the uncertainties for the reconstructed h(t) strain, estimated in this paper in a 20-2000 hz frequency band, are frequency independent: 5% in amplitude, 35 mrad in phase and 10 μs in timing, with the exception of larger uncertainties around 50 hz. | calibration of advanced virgo and reconstruction of the detector strain h(t) during the observing run o3 |
first-order phase transitions exist in many models beyond the standard model and can generate detectable stochastic gravitational waves for a strong one. using the cosmological observables in big bang nucleosynthesis and cosmic microwave background, we derive constraints on the phase transition temperature and strength parameter in a model-independent way. for a strong phase transition, we find that the phase transition temperature should be above around 2 mev for both reheating photon and neutrino cases. for a weak one with the temperature below 1 mev, the phase transition strength parameter is constrained to be smaller than around 0.1. implications for using a first-order phase transition to explain the nanograv observed signal are also discussed. | cosmological constraints on first-order phase transitions |
the discovery of the super-giant coral and mamba gas fields in the offshore of northern mozambique provides a unique insight into the architecture of a new deep-water play-type. high-quality seismic and extensive well data from both fields shows that very clean (clay matrix-poor) sandstone reservoirs, with thickness >100 m and extended over tens of km can be formed by the syndepositional interaction of down-slope high-density turbulent gravity flows and across-slope bottom currents. this is recorded by: i) the marked asymmetry of submarine channels and lateral stacking in which top-of-fan seismic reflectors show a lateral transition from high to low amplitude response from axis to off-axis locations; ii) the occurrence of laterally-deviated lobe deposits, sediment waves and channel-associated drifts in the inferred bottom current direction; iii) the presence of very clean sandstones forming the bulk of the fan units and the consistent lack of interbedded fine-grained facies; iv) the occurrence of fine-grained and thin-bedded facies adjacent to the main fan axes, which are characterized by repeated transitions between ripples and parallel-laminated sandstones, mud-drapes, shale clasts and bi-directional cross-laminae in the same bed, indicating intense traction and velocity pulsations. this association forms a mixed depositional system, in which only the basal and coarse-grained part of the turbidity current load is deposited and preserved in the axial part of the system, whilst all the finer-grained sediments are pirated from the turbulent cloud by laterally flowing bottom currents and deposited in the adjacent sediment drifts. the inferred process results in exceptionally high quality reservoirs whose architectural and facies models were confirmed by the appraisal campaign and production well tests and incorporated into the reservoir model. the results of this study indicate a significant exploration potential in similar geological settings and the definition of a potential new play type, that could lead to the reinterpretation of existing deep-water datasets. | a new world-class deep-water play-type, deposited by the syndepositional interaction of turbidity flows and bottom currents: the giant eocene coral field in northern mozambique |
if the mass of dark matter is generated from a cosmological phase transition involving the nucleation of bubbles, the corresponding bubble walls can filter out dark matter particles during the phase transition. only particles with sufficient momentum to overcome their mass inside the bubbles can pass through the walls. as a result, the dark matter number density after the phase transition has a suppression factor exp (-mχ/2 γ ∼t ), where mχ is the dark matter mass, and γ ∼ and t are the lorentz factor and temperature of the incoming fluid in the bubble wall rest frame, respectively. under certain assumptions, we show that the filtering-out process can naturally provide a large suppression consistent with the observed dark matter density for a wide range of dark matter masses up to the planck scale. since the first-order phase transition is the decisive ingredient in our mechanism, a new connection is made between heavy dark matter scenarios and gravitational wave observations. | dark matter filtering-out effect during a first-order phase transition |
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