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2023-05-13
Global existence for a 3D Tropical Climate Model with damping and small initial data in $\dot H^{1/2}(\mathbb{R}^3)$
We consider a 3D Tropical Climate Model with damping terms in the equation of the barotropic mode $u$ and in the equation of the first baroclinic mode $v$ of the velocity. The equation for the temperature $\theta$ is free from dampings. We prove global existence in time for this system assuming the initial data $(u_0, ...
2305.07964v1
2023-06-21
The effect of singularities and damping on the spectra of photonic crystals
Understanding the dispersive properties of photonic crystals is a fundamental and well-studied problem. However, the introduction of singular permittivities and damping complicates the otherwise straightforward theory. In this paper, we study photonic crystals with a Drude-Lorentz model for the permittivity, motivated ...
2306.12254v1
2023-07-12
Asymptotic behavior of solutions to the Cauchy problem for 1-D p-system with space dependent damping
We consider the Cauchy problem for one-dimensional p-system with damping of space-dependent coefficient. This system models the compressible flow through porous media in the Lagrangean coordinate. Our concern is an asymptotic behavior of solutions, which is expected to be the diffusion wave based on the Darcy law. To s...
2307.05865v1
2023-07-12
Parabolic-elliptic Keller-Segel's system
We study on the whole space R d the compressible Euler system with damping coupled to the Poisson equation when the damping coefficient tends towards infinity. We first prove a result of global existence for the Euler-Poisson system in the case where the damping is large enough, then, in a second step, we rigorously ju...
2307.05981v1
2023-07-25
Asymptotic behavior and life-span estimates for the damped inhomogeneous nonlinear Schrödinger equation
We are interested in the behavior of solutions to the damped inhomogeneous nonlinear Schr\"odinger equation $ i\partial_tu+\Delta u+\mu|x|^{-b}|u|^{\alpha}u+iau=0$, $\mu \in\mathbb{C} $, $b>0$, $a \in \mathbb{C}$ such that $\Re \textit{e}(a) \geq 0$, $\alpha>0$. We establish lower and upper bound estimates of the life-...
2307.13495v1
2023-07-26
On nonlinear Landau damping and Gevrey regularity
In this article we study the problem of nonlinear Landau damping for the Vlasov-Poisson equations on the torus. As our main result we show that for perturbations initially of size $\epsilon>0$ and time intervals $(0,\epsilon^{-N})$ one obtains nonlinear stability in regularity classes larger than Gevrey $3$, uniformly ...
2307.14271v1
2023-08-18
Damping for fractional wave equations and applications to water waves
Motivated by numerically modeling surface waves for inviscid Euler equations, we analyze linear models for damped water waves and establish decay properties for the energy for sufficiently regular initial configurations. Our findings give the explicit decay rates for the energy, but do not address reflection/transmissi...
2308.09288v1
2023-08-30
Optimal decay for one-dimensional damped wave equations with potentials via a variant of Nash inequality
The optimality of decay properties of the one-dimensional damped wave equations with potentials belonging to a certain class is discussed. The typical ingredient is a variant of Nash inequality which involves an invariant measure for the corresponding Schr\"odinger semigroup. This enables us to find a sharp decay estim...
2308.15680v1
2023-09-15
Explicit solutions and linear inviscid damping in the Euler-Boussinesq equation near a stratified Couette flow in the periodic strip
This short note provides explicit solutions to the linearized Boussinesq equations around the stably stratified Couette flow posed on $\mathbb{T}\times\mathbb{R}$. We consider the long-time behavior of such solutions and prove inviscid damping of the perturbed density and velocity field for any positive Richardson numb...
2309.08419v2
2023-09-21
Beyond Qubits : An Extensive Noise Analysis for Qutrit Quantum Teleportation
The four quantum noises Bit Flip, Phase Flip, Depolarization, and Amplitude Damping as well as any potential combinations of them are examined in this papers investigation of quantum teleportation using qutrit states. Among the above mentioned noises, we observed phase flip has highest fidelity. Compared to uncorrelate...
2309.12163v1
2023-12-22
Soliton resolution for the energy critical damped wave equations in the radial case
We consider energy-critical damped wave equation \begin{equation*} \partial_{tt}u-\Delta u+\alpha \partial_t u=\left|u\right|^{\frac{4}{D-2}}u \end{equation*} with radial initial data in dimensions $D\geq 4$. The equation has a nontrivial radial stationary solution $W$, called the ground state, which is unique up to si...
2401.04115v2
2024-01-22
Damping-Enhanced Magnon Transmission
The inevitable Gilbert damping in magnetization dynamics is usually regarded as detrimental to spin transport. Here we demonstrate in a ferromagnetic-insulator--normal-metal heterostructure that the strong momentum dependence and chirality of the eddy-current-induced damping causes also beneficial scattering properties...
2401.12022v1
2024-02-18
Sharp lifespan estimate for the compressible Euler system with critical time-dependent damping in $\R^2$
This paper concerns the long time existence to the smooth solutions of the compressible Euler system with critical time dependent damping in $\R^2$. We establish the sharp lifespan estimate from below, with respect to the small parameter of the initial perturbation. For this end, the vector fields $\widehat{Z}$ (define...
2402.11516v1
2024-02-28
Linear inviscid damping in the presence of an embedding eigenvalue
In this paper, we investigate the long-time dynamics of the linearized 2-D Euler equations around a hyperbolic tangent flow $(\tanh y,0)$. A key difference compared to previous results is that the linearized operator has an embedding eigenvalue, which has a significant impact on the dynamics of the linearized system. F...
2402.18229v1
2024-03-19
Improved decay results for micropolar flows with nonlinear damping
We examine the long-time behavior of solutions (and their derivatives) to the micropolar equations with nonlinear velocity damping. Additionally, we get a speed-up gain of $ t^{1/2} $ for the angular velocity, consistent with established findings for classic micropolar flows lacking nonlinear damping. Consequently, we ...
2403.12885v1
2024-03-26
On a class of nonautonomous quasilinear systems with general time-gradually-degenerate damping
In this paper, we study two systems with a time-variable coefficient and general time-gradually-degenerate damping. More explicitly, we construct the Riemann solutions to the time-variable coefficient Zeldovich approximation and time-variable coefficient pressureless gas systems both with general time-gradually-degener...
2403.17732v1
2024-04-09
Phase space contraction of degenerately damped random splittings
When studying out-of-equilibrium systems, one often excites the dynamics in some degrees of freedom while removing the excitation in others through damping. In order for the system to converge to a statistical steady state, the dynamics must transfer the energy from the excited modes to the dissipative directions. The ...
2404.06465v1
2002-09-30
The Cosmic Microwave Background & Inflation, Then & Now
Boomerang, Maxima, DASI, CBI and VSA significantly increase the case for accelerated expansion in the early universe (the inflationary paradigm) and at the current epoch (dark energy dominance), especially when combined with data on high redshift supernovae (SN1) and large scale structure (LSS). There are ``7 pillars o...
0210007v1
2003-06-17
Kinetic equilibrium of iron in the atmospheres of cool stars III. The ionization equilibrium of selected reference stars
Non-LTE line formation calculations of Fe I are performed for a small number of reference stars to investigate and quantify the efficiency of neutral hydrogen collisions. Using the atomic model that was described in previous publications, the final discrimination with respect to hydrogen collisions is based on the cond...
0306337v1
2003-10-08
Signatures of Relativistic Neutrinos in CMB Anisotropy and Matter Clustering
We present a detailed analytical study of ultra-relativistic neutrinos in cosmological perturbation theory and of the observable signatures of inhomogeneities in the cosmic neutrino background. We note that a modification of perturbation variables that removes all the time derivatives of scalar gravitational potentials...
0310198v3
2004-09-22
First stars VI - Abundances of C, N, O, Li, and mixing in extremely metal-poor giants. Galactic evolution of the light elements
We have investigated the poorly-understood origin of nitrogen in the early Galaxy by determining N abundances in 35 extremely metal-poor halo giants (22 stars have [Fe/H]<-3.0) using the C and O abundances determined in Paper V. Because any dredge-up of CNO processed material to the surface may complicate the interpret...
0409536v3
2005-09-15
Damped Lyman Alpha Systems at z<1.65: The Expanded SDSS HST Sample
We present results of our HST Cycle 11 Survey for low-redshift (z<1.65) DLAs in the UV spectra of quasars selected from the SDSS Early Data Release. These quasars have strong intervening MgII-FeII systems which are known signatures of high column density neutral gas. In total, UV observations of Ly-alpha absorption in ...
0509469v1
2007-01-03
HI 21cm absorption at $z \sim 3.39$ towards PKS 0201+113
We report the GMRT detection of HI 21cm absorption from the $z \sim 3.39$ damped Lyman-$\alpha$ absorber (DLA) towards PKS 0201+113, the highest redshift at which 21cm absorption has been detected in a DLA. The absorption is spread over $\sim 115$ km s$^{-1}$ and has two components, at $z = 3.387144 (17)$ and $z = 3.38...
0701074v2
2004-10-24
Field theory of the inverse cascade in two-dimensional turbulence
A two-dimensional fluid, stirred at high wavenumbers and damped by both viscosity and linear friction, is modeled by a statistical field theory. The fluid's long-distance behavior is studied using renormalization-group (RG) methods, as begun by Forster, Nelson, and Stephen [Phys. Rev. A 16, 732 (1977)]. With friction, ...
0410050v2
2004-09-20
Effect of the Vacuum Energy Density on Graviton Propagation
It is known that the value L of the vacuum energy density affects the propagation equation for gravitons: A mass term appears in the propagation equation, such that m^2=-L. As a consequence, the polarization states of gravitons also change. This effect of the L-term has been confirmed by recent calculations in a curved...
0409098v1
2006-07-02
Physics of Flow Instability and Turbulent Transition in Shear Flows
In this paper, the physics of flow instability and turbulent transition in shear flows is studied by analyzing the energy variation of fluid particles under the interaction of base flow with a disturbance. For the first time, a model derived strictly from physics is proposed to show that the flow instability under fini...
0607004v5
2007-06-25
Toward faithful templates for non-spinning binary black holes using the effective-one-body approach
We present an accurate approximation of the full gravitational radiation waveforms generated in the merger of non-eccentric systems of two non-spinning black holes. Utilizing information from recent numerical relativity simulations and the natural flexibility of the effective-one-body (EOB) model, we extend the latter ...
0706.3732v3
2007-08-06
Ejection of Supermassive Black Holes from Galaxy Cores
[Abridged] Recent numerical relativity simulations have shown that the emission of gravitational waves during the merger of two supermassive black holes (SMBHs) delivers a kick to the final hole, with a magnitude as large as 4000 km/s. We study the motion of SMBHs ejected from galaxy cores by such kicks and the effects...
0708.0771v2
2007-11-19
Effect of the intergalactic environment on the observability of Ly-alpha emitters during reionization
Observations of high-redshift Ly-alpha sources are a major tool for studying the high-redshift Universe. We discuss the effect of the reionizing intergalactic medium on the observability of Ly-alpha sources based on large simulations of early structure formation with radiative transfer. This takes into account self-con...
0711.2944v2
2007-12-17
The Nitrogen and Oxygen abundances in the neutral gas at high redshift
We study the Oxygen and Nitrogen abundances in the interstellar medium of high-redshift galaxies. We use high resolution and high signal-to-noise ratio spectra of Damped Lyman-alpha (DLA) systems detected along the line-of-sight to quasars to derive robust abundance measurements from unsaturated metal absorption lines....
0712.2760v1
2008-10-26
Non-linear Study of Bell's Cosmic Ray Current-driven Instability
The cosmic ray current-driven (CRCD) instability, predicted by Bell (2004), consists of non-resonant, growing plasma waves driven by the electric current of cosmic rays (CRs) that stream along the magnetic field ahead of both relativistic and non-relativistic shocks. Combining an analytic, kinetic model with one-, two-...
0810.4565v1
2008-10-27
Determination of the neutron star mass-radii relation using narrow-band gravitational wave detector
The direct detection of gravitational waves will provide valuable astrophysical information about many celestial objects. The most promising sources of gravitational waves are neutron stars and black holes. These objects emit waves in a very wide spectrum of frequencies determined by their quasi-normal modes oscillatio...
0810.4848v4
2009-02-17
21-cm absorbers at intermediate redshifts
Damped Lyman-alpha systems (DLAs) seen in the spectra of high-z QSOs allow us to probe the physical conditions in protogalaxies. Our understanding of physical conditions in DLAs at high-z is primarily based on the absorption lines of H_2 molecules and fine-structure transitions. Another important way of probing the the...
0902.3016v1
2009-08-27
Very Light Magnetized Jets on Large Scales - I. Evolution and Magnetic Fields
Magnetic fields, which are undoubtedly present in extragalactic jets and responsible for the observed synchrotron radiation, can affect the morphology and dynamics of the jets and their interaction with the ambient cluster medium. We examine the jet propagation, morphology and magnetic field structure for a wide range ...
0908.4055v1
2009-10-12
Average luminosity distance in inhomogeneous universes
The paper studies the correction to the distance modulus induced by inhomogeneities and averaged over all directions from a given observer. The inhomogeneities are modeled as mass-compensated voids in random or regular lattices within Swiss-cheese universes. Void radii below 300 Mpc are considered, which are supported ...
0910.2611v3
2009-12-22
Rest-frame ultraviolet spectrum of the gravitationally lensed galaxy `the 8 o'clock arc': stellar and interstellar medium properties
We present the first detailed analysis of the rest-frame UV spectrum of the gravitationally lensed Lyman break galaxy (LBG), the `8 o'clock arc'. The spectrum of the 8 o'clock arc is rich in stellar and interstellar medium (ISM) features, and presents several similarities to the well-known MS1512-cB58 LBG. The stellar ...
0912.4384v1
2010-07-19
The Evolution of Lyman Limit Absorption Systems to Redshift Six
We have measured the redshift evolution of the density of Lyman limit systems (LLS) in the intergalactic medium over the redshift range 0 < z < 6. We have used two new quasar samples to (1) improve coverage at z ~ 1, with GALEX grism spectrograph observations of 50 quasars with 0.8 < z_em < 1.3, and (2) extend coverage...
1007.3262v2
2010-11-01
A Model for Thermal Phase Variations of Circular and Eccentric Exoplanets
We present a semi-analytic model atmosphere for close-in exoplanets that captures the essential physics of phase curves: orbital and viewing geometry, advection, and re-radiation. We calibrate the model with the well-characterized transiting planet, HD 189733b, then compute light curves for seven of the most eccentric ...
1011.0428v1
2010-12-16
Constraints on coronal turbulence models from source sizes of noise storms at 327 MHz
We seek to reconcile observations of small source sizes in the solar corona at 327 MHz with predictions of scattering models that incorporate refractive index effects, inner scale effects and a spherically diverging wavefront. We use an empirical prescription for the turbulence amplitude $C_{N}^{2}(R)$ based on VLBI ob...
1012.3523v2
2011-01-25
The Surprisingly Constant Strength of O VI Absorbers over Cosmic Time
O VI absorption is observed in a wide range of astrophysical environments, including the Local ISM, the disk and halo of the Milky Way, high-velocity clouds, the Magellanic clouds, starburst galaxies, the intergalactic medium, damped Lyman-alpha systems, and gamma-ray-burst host galaxies. Here a new compilation of 775 ...
1101.4766v1
2011-03-21
A Groundbased Imaging Study of Galaxies Causing DLA, subDLA, and LLS Absorption in Quasar Spectra
We present results from a search for galaxies that give rise to damped Lyman alpha (DLA), subDLA, and Lyman limit system (LLS) absorption at redshifts 0.1 ~< z ~< 1 in the spectra of background quasars. The sample was formed from a larger sample of strong MgII absorbers (W_0^(2796) >= 0.3 A) whose HI column densities w...
1103.4047v3
2011-05-06
Non-relativistic bound states in a moving thermal bath
We study the propagation of non-relativistic bound states moving at constant velocity across a homogeneous thermal bath and we develop the effective field theory which is relevant in various dynamical regimes. We consider values of the velocity of the bound state ranging from moderate to highly relativistic and tempera...
1105.1249v2
2011-08-24
Dynamical Tides in Compact White Dwarf Binaries: Tidal Synchronization and Dissipation
In compact white dwarf (WD) binary systems (with periods ranging from minutes to hours), dynamical tides involving the excitation and dissipation of gravity waves play a dominant role in determining the physical conditions of the WDs prior to mass transfer or binary merger. We calculate the amplitude of the tidally exc...
1108.4910v5
2011-11-22
Coronal heating in coupled photosphere-chromosphere-coronal systems: turbulence and leakage
Coronal loops act as resonant cavities for low frequency fluctuations that are transmitted from the deeper layers of the solar atmosphere and are amplified in the corona, triggering nonlinear interactions. However trapping is not perfect, some energy leaks down to the chromosphere, thus limiting the turbulence developm...
1111.5359v1
2012-06-22
Cosmic Acceleration from Causal Backreaction with Recursive Nonlinearities
We revisit the causal backreaction paradigm, in which the need for Dark Energy is eliminated via the generation of an apparent cosmic acceleration from the causal flow of inhomogeneity information coming in towards each observer from distant structure-forming regions. This second-generation formalism incorporates "recu...
1206.5056v1
2012-10-10
Bodily tides near the 1:1 spin-orbit resonance. Correction to Goldreich's dynamical model
Spin-orbit coupling is often described in the "MacDonald torque" approach which has become the textbook standard. Within this method, a concise expression for the additional tidal potential, derived by MacDonald (1964; Rev. Geophys. 2, 467), is combined with an assumption that the Q factor is frequency-independent (i.e...
1210.2923v3
2012-11-06
Tidal resonance locks in inspiraling white dwarf binaries
We calculate the tidal response of helium and carbon/oxygen (C/O) white dwarf (WD) binaries inspiraling due to gravitational wave emission. We show that resonance locks, previously considered in binaries with an early-type star, occur universally in WD binaries. In a resonance lock, the orbital and spin frequencies evo...
1211.1393v4
2013-06-17
GRB 130606A as a Probe of the Intergalactic Medium and the Interstellar Medium in a Star-forming Galaxy in the First Gyr After the Big Bang
We present high signal-to-noise ratio Gemini and MMT spectroscopy of the optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z=5.913, discovered by Swift. This is the first high-redshift GRB afterglow to have spectra of comparable quality to those of z~6 quasars. The data exhibit a smooth continuum at ne...
1306.3949v2
2013-10-31
Spatially Resolved Emission of a High Redshift DLA Galaxy with the Keck/OSIRIS IFU
We present the first Keck/OSIRIS infrared IFU observations of a high redshift damped Lyman-alpha (DLA) galaxy detected in the line of sight to a background quasar. By utilizing the Laser Guide Star Adaptive Optics (LGSAO) to reduce the quasar PSF to FWHM~0.15 arcsec, we were able to search for and map the foreground DL...
1311.0045v1
2013-11-29
Continuous Emission of A Radiation Quantum
It is in accordance with such experiments as single photon self-interference that a photon, conveying one radiation energy quantum "$ h \times$ frequency", is spatially extensive and stretches an electromagnetic wave train. A wave train, hence an energy quantum, can only be emitted by its source gradually. In both the ...
1312.0918v1
2014-02-06
Dynamics of Order Parameters near Stationary States in Superconductors with a Charge-Density Wave
We consider a simple model of a quasi-one-dimensional conductor in which two order parameters (OP) may coexist, i.e., the superconducting OP $\Delta$ and the OP $W$ that characterizes the amplitude of a charge-density wave (CDW). In the mean field approximation we present equations for the matrix Green's functions $G_{...
1402.1411v4
2014-05-28
GRB 140515A at z=6.33: Constraints on the End of Reionization From a Gamma-ray Burst in a Low Hydrogen Column Density Environment
We present the discovery and subsequent spectroscopy with Gemini-North of the optical afterglow of the Swift gamma-ray burst (GRB) 140515A. The spectrum exhibits a well-detected continuum at wavelengths longer than 8915 Angs with a steep decrement to zero flux blueward of 8910 Angs due to Ly-alpha absorption at redshif...
1405.7400v1
2014-08-24
Thickness dependence of dynamic and static magnetic properties of pulsed laser deposited La$_{0.7}$Sr$_{0.3}$MnO$_3$ films on SrTiO$_3$(001)
We present a comprehensive study of the thickness dependence of static and magneto-dynamic magnetic properties of La$_{0.7}$Sr$_{0.3}$MnO$_3$. Epitaxial pulsed laser deposited La$_{0.7}$Sr$_{0.3}$MnO$_3$ / SrTiO$_3$(001) thin films in the range from 3 unit cells (uc) to 40 uc (1.2 - 16 nm) have been investigated throug...
1408.5631v1
2015-01-27
Comparative analysis of existing models for power-grid synchronization
The dynamics of power-grid networks is becoming an increasingly active area of research within the physics and network science communities. The results from such studies are typically insightful and illustrative, but are often based on simplifying assumptions that can be either difficult to assess or not fully justifie...
1501.06926v2
2015-04-28
A meeting point of entropy and bifurcations in cross-diffusion herding
A cross-diffusion system modeling the information herding of individuals is analyzed in a bounded domain with no-flux boundary conditions. The variables are the species' density and an influence function which modifies the information state of the individuals. The cross-diffusion term may stabilize or destabilize the s...
1504.07555v4
2015-05-29
Microscopic Theory for Coupled Atomistic Magnetization and Lattice Dynamics
A coupled atomistic spin and lattice dynamics approach is developed which merges the dynamics of these two degrees of freedom into a single set of coupled equations of motion. The underlying microscopic model comprises local exchange interactions between the electron spin and magnetic moment and the local couplings bet...
1505.08005v3
2015-06-18
Galaxy power spectrum in redshift space: combining perturbation theory with the halo model
Theoretical modeling of the redshift-space power spectrum of galaxies is crucially important to correctly extract cosmological information from redshift surveys. The task is complicated by the nonlinear biasing and redshift space distortion effects, which change with halo mass, and by the wide distribution of halo mass...
1506.05814v2
2015-10-25
A class of chemotaxis systems with growth source and nonlinear secretion
In this paper, we are concerned with a class of parabolic-elliptic chemotaxis systems encompassing the prototype $$\left\{\begin{array}{lll} &u_t = \nabla\cdot(\nabla u-\chi u\nabla v)+f(u), & x\in \Omega, t>0, \\[0.2cm] &0= \Delta v -v+u^\kappa, & x\in \Omega, t>0 \end{array}\right. $$ with nonnegative initial conditi...
1510.07204v1
2017-01-20
On the Transition from Potential Flow to Turbulence Around a Microsphere Oscillating in Superfluid ^4He
The flow of superfluid $^4$He around a translationally oscillating sphere, levitating without mechanical support, can either be laminar or turbulent, depending on the velocity amplitude. Below a critical velocity $v_c$ that scales as $\omega ^{1/2}$, and is temperature independent below 1 K, the flow is laminar (potent...
1701.05733v2
2017-02-04
Brightness Temperature of Radio Zebras and Wave Energy Densities in Their Sources
We estimated the brightness temperature of radio zebras (zebra pattern -- ZP), considering that ZPs are generated in loops having an exponential density profile in their cross-section. We took into account that when in plasma there is a source emitting in all directions, then in the escape process from the plasma the e...
1702.01278v2
2017-03-02
Pinch dynamics in a low-$β$ plasma
The relaxation of a helical magnetic field ${\bf B}({\bf x}, t)$ in a high-conductivity plasma contained in the annulus between two perfectly conducting coaxial cylinders is considered. The plasma is of low density and its pressure is negligible compared with the magnetic pressure; the flow of the plasma is driven by t...
1703.00708v1
2017-04-18
Outbursts of the intermediate-mass black hole HLX-1: a wind instability scenario
We model the intermediate-mass black hole HLX-1, using the Hubble Space Telescope, XMM-Newton and Swift. We quantify the relative contributions of a bluer component, function of X-ray irradiation, and a redder component, constant and likely coming from an old stellar population. We estimate a black hole mass of about (...
1704.05468v1
2017-07-04
Lattice symmetries and the topological protected transport of colloidal particles
The topologically protected transport of colloidal particles on top of magnetic patterns of all possible single lattice constant two dimensional magnetic point group symmetries is studied experimentally, theoretically, and with numerical simulations. We examine the transport of colloidal particles in response to modula...
1707.00861v1
2017-10-05
Cross section alignment of polycyclic aromatic hydrocarbons by anisotropic radiation
We study the effect of anisotropic radiation illumination on the alignment of polycyclic aromatic hydrocarbons (PAHs) and report that cross-sectional mechanism of alignment earlier considered in terms of gas-grain interactions can also be efficient for the photon-grain interaction. We demonstrate this by first calculat...
1710.01835v2
2018-05-15
Nonreciprocal charge transport in two-dimensional noncentrosymmetric superconductors
Nonreciprocal charge transport phenomena are studied theoretically for two-dimensional noncentrosymmetric superconductors under an external magnetic field $B$. Rashba superconductors, surface superconductivity on the surface of three-dimensional topological insulators, and transition metal dichalcogenides (TMD) are rep...
1805.05735v1
2018-07-27
Phase spreading and temporal coherence of a pair-condensed Fermi gas at low temperature
A condensate of pairs in an isolated, homogeneous, unpolarised, finite-size spin 1/2 Fermi gas at low nonzero temperature T, undergoes with time a phase change with a random component, due to coupling to the gas thermal phonons. With the quantum second Josephson relation relating the derivative of the condensate phase ...
1807.10476v2
2018-09-24
Laser cooling and magneto-optical trapping of molecules analyzed using optical Bloch equations and the Fokker-Planck-Kramers equation
We study theoretically the behavior of laser-cooled calcium monofluoride (CaF) molecules in an optical molasses and magneto-optical trap (MOT), and compare our results to recent experiments. We use multi-level optical Bloch equations to estimate the force and the diffusion constant, followed by a Fokker-Planck-Kramers ...
1809.08833v4
2019-02-01
The Neutrino Puzzle: Anomalies, Interactions, and Cosmological Tensions
New physics in the neutrino sector might be necessary to address anomalies between different neutrino oscillation experiments. Intriguingly, it also offers a possible solution to the discrepant cosmological measurements of $H_0$ and $\sigma_8$. We show here that delaying the onset of neutrino free-streaming until close...
1902.00534v2
2019-01-31
Analysis and active control of geometrically nonlinear responses of smart FG porous plates with graphene nanoplatelets reinforcement based on Bézier extraction of NURBS
In this paper, we propose an effective computational approach to analyze and active control of geometrically nonlinear responses of functionally graded (FG) porous plates with graphene nanoplatelets (GPLs) reinforcement integrated with piezoelectric layers. The key concept behind this work is to utilize isogeometric an...
1902.10806v2
2019-03-19
Phase mixing of nonlinear Alfven waves
Aims: This paper presents 2.5D numerical experiments of Alfv\'en wave phase mixing and aims to assess the effects of nonlinearities on wave behaviour and dissipation. In addition, this paper aims to quantify how effective the model presented in this work is at providing energy to the coronal volume. Methods: The mode...
1903.08093v1
2019-07-30
Rapid Reionization by the Oligarchs: The Case for Massive, UV-Bright, Star-Forming Galaxies with High Escape Fractions
The protagonists of cosmic reionization remain elusive. Faint star-forming galaxies are leading candidates because they are numerous and may have significant ionizing photon escape fractions ($f_{esc}$). Here we update this picture via an empirical model that successfully predicts latest observations (e.g., the drop in...
1907.13130v2
2019-09-13
Multi-Particle Collisions in Microgravity: Coefficient of Restitution and Sticking Threshold for Systems of Mm-Sized Particles
The current model of planet formation lacks a good understanding of the growth of dust particles inside the protoplanetary disk beyond mm sizes. In order to investigate the low-velocity collisions between this type of particles, the NanoRocks experiment was flown on the International Space Station (ISS) between Septemb...
1909.06417v1
2019-10-14
A search for optical AGN variability in 35,000 low-mass galaxies with the Palomar Transient Factory
We present an analysis of the long-term optical variability for $\sim50,000$ nearby (z<0.055) galaxies from the NASA-Sloan Atlas, $35,000$ of which are low-mass ($M_{\ast}<10^{10}~M_{\odot}$). We use difference imaging of Palomar Transient Factory (PTF) R-band observations to construct light curves with typical baselin...
1910.06342v1
2019-10-30
A priori bounds for the $Φ^4$ equation in the full sub-critical regime
We derive a priori bounds for the $\Phi^4$ equation in the full sub-critical regime using Hairer's theory of regularity structures. The equation is formally given by \begin{equation} \label{e}(\partial_t-\Delta)\phi = -\phi^3 + \infty \phi +\xi, \tag{$\star$} \end{equation} where the term $+\infty \phi$ represents infi...
1910.13854v2
2019-10-31
One-point probability distribution function from spherical collapse: Early Dark Energy (EDE) vs. $Λ$CDM
We compute the one-point PDF of an initially Gaussian dark matter density field using spherical collapse (SC). We compare the results to other forms available in the literature and also compare the PDFs in the $\Lambda$CDM model with an early dark energy (EDE) model. We find that the skewed log-normal distribution prov...
1910.14347v3
2019-11-04
Planet-disk interaction in disks with cooling: basic theory
Gravitational coupling between young planets and their parent disks is often explored using numerical simulations, which typically treat the disk thermodynamics in a highly simplified manner. In particular, many studies adopt the locally isothermal approximation, in which the disk temperature is a fixed function of the...
1911.01428v2
2019-11-18
Wave measurements from ship mounted sensors in the Arctic marginal ice zone
Increased research interest and economic activity in the Arctic raise the need for new observations of sea ice dynamics. Remote sensing as well as mathematical and numerical models of wave propagation in sea ice would benefit from more in situ data for validation. This study presents wave measurements in the marginal i...
1911.07612v2
2019-11-29
Convection-dominated dissolution for single and multiple immersed sessile droplets
We numerically investigate both single and multiple droplet dissolution with droplets consisting of lighter liquid dissolving in a denser host liquid. The significance of buoyancy is quantified by the Rayleigh number Ra which is the buoyancy force over the viscous damping force. In this study, Ra spans almost four deca...
1911.13040v1
2020-02-26
The Magnetized Vlasov-Ampère system and the Bernstein-Landau paradox
We study the Bernstein-Landau paradox in the collisionless motion of an electrostatic plasma in the presence of a constant external magnetic field. The Bernstein-Landau paradox consists in that in the presence of the magnetic field, the electric field and the charge density fluctuation have an oscillatory behavior in t...
2002.11380v3
2020-07-24
Convective turbulent viscosity acting on equilibrium tidal flows: new frequency scaling of the effective viscosity
Turbulent convection is thought to act as an effective viscosity ($\nu_E$) in damping tidal flows in stars and giant planets. However, the efficiency of this mechanism has long been debated, particularly in the regime of fast tides, when the tidal frequency ($\omega$) exceeds the turnover frequency of the dominant conv...
2007.12624v1
2020-10-05
Cryogenic suspension design for a kilometer-scale gravitational-wave detector
We report the mirror suspension design for Large-scale Cryogenic Gravitational wave Telescope, KAGRA, during bKAGRA Phase 1. Mirror thermal noise is one of the fundamental noises for room-temperature gravitational-wave detectors such as Advanced LIGO and Advanced Virgo. Thus, reduction of thermal noise is required for ...
2010.01889v2
2021-01-21
A Gauss-Seidel projection method with the minimal number of updates for stray field in micromagnetic simulations
Magnetization dynamics in magnetic materials is often modeled by the Landau-Lifshitz equation, which is solved numerically in general. In micromagnetic simulations, the computational cost relies heavily on the time-marching scheme and the evaluation of stray field. Explicit marching schemes are efficient but suffer fro...
2101.08574v1
2021-01-29
Radiative Poincare type eon and its follower
We consider two consecutive eons $\hat{M}$ and $\check{M}$ from Penrose's Conformal Cyclic Cosmology and study how the matter content of the past eon ($\hat{M}$) determines the matter content of the present eon ($\check{M}$) by means of the reciprocity hypothesis. We assume that the only matter content in the final sta...
2101.12670v2
2021-03-24
Magnetism and Spin Dynamics in Room-Temperature van der Waals Magnet Fe$_5$GeTe$_2$
Two-dimensional (2D) van der Waals (vdWs) materials have gathered a lot of attention recently. However, the majority of these materials have Curie temperatures that are well below room temperature, making it challenging to incorporate them into device applications. In this work, we synthesized a room-temperature vdW ma...
2103.13433v2
2021-07-25
High-overtone fits to numerical relativity ringdowns: beyond the dismissed n=8 special tone
In general relativity, the remnant object originating from an uncharged black hole merger is a Kerr black hole. The approach to this final state is reached through the emission of a late train of radiation known as the black hole ringdown. The ringdown morphology is described by a countably infinite set of damped sinus...
2107.11829v2
2021-12-23
Real-time methods for spectral functions
In this paper we develop and compare different real-time methods to calculate spectral functions. These are classical-statistical simulations, the Gaussian state approximation (GSA), and the functional renormalization group (FRG) formulated on the Keldysh closed-time path. Our test-bed system is the quartic anharmonic ...
2112.12568v3
2022-01-03
Exact scalar (quasi-)normal modes of black holes and solitons in gauged SUGRA
In this paper we identify a new family of black holes and solitons that lead to the exact integration of scalar probes, even in the presence of a non-minimal coupling with the Ricci scalar which has a non-trivial profile. The backgrounds are planar and spherical black holes as well as solitons of $SU\left( 2\right) \ti...
2201.00438v1
2022-06-02
Axion dark matter from frictional misalignment
We study the impact of sphaleron-induced thermal friction on the axion dark-matter abundance due to the interaction of an axion-like particle (ALP) with a dark non-abelian gauge sector in a secluded thermal bath. Thermal friction can either enhance the axion relic density by delaying the onset of oscillations or suppre...
2206.01129v3
2022-06-11
Field evolution of magnetic phases and spin dynamics in the honeycomb lattice magnet Na2Co2TeO6: 23Na NMR study
We report on the results of 23Na NMR in the honeycomb lattice magnet Na2Co2TeO6 which has been nominated as a Kitaev material. Measurements of magnetic shift and width of the NMR line as functions of temperature and magnetic field show that a spin-disordered phase does not appear up to a field of 9 T. In the antiferrom...
2206.05409v3
2022-07-05
Emergence of a new HI 21-cm absorption component at z~1.1726 towards the gamma-ray blazar PKS~2355-106
We report the emergence of a new HI 21-cm absorption at z_abs = 1.172635 in the damped Lyman-alpha absorber (DLA) towards the gamma-ray blazar PKS 2355-106 (z_em~1.639) using science verification observations (June 2020) from the MeerKAT Absorption Line Survey (MALS). Since 2006, this DLA is known to show a narrow HI 2...
2207.01807v1
2022-07-29
Global spherically symmetric solutions to degenerate compressible Navier-Stokes equations with large data and far field vacuum
We consider the initial-boundary value problem (IBVP) for the isentropic compressible Navier-Stokes equations (\textbf{CNS}) in the domain exterior to a ball in $\mathbb R^d$ $(d=2\ \text{or} \ 3)$. When viscosity coefficients are given as a constant multiple of the mass density $\rho$, based on some analysis of the no...
2207.14494v1
2022-10-13
The Planck clusters in the LOFAR sky. III. LoTSS-DR2: Dynamic states and density fluctuations of the intracluster medium
The footprint of LoTSS-DR2 covers 309 PSZ2 galaxy clusters, 83 of which host a radio halo and 26 host a radio relic(s). It provides us an excellent opportunity to statistically study the properties of extended cluster radio sources, especially their connection with merging activities. We aim to quantify cluster dynamic...
2210.07284v1
2022-11-03
Skyrmion Jellyfish in Driven Chiral Magnets
Chiral magnets can host topological particles known as skyrmions, which carry an exactly quantised topological charge $Q=-1$. In the presence of an oscillating magnetic field ${\bf B}_1(t)$, a single skyrmion embedded in a ferromagnetic background will start to move with constant velocity ${\bf v}_{\text{trans}}$. The ...
2211.01714v5
2022-12-12
Modified propagation of gravitational waves from the early radiation era
We study the propagation of cosmological gravitational wave (GW) backgrounds from the early radiation era until the present day in modified theories of gravity. Comparing to general relativity (GR), we study the effects that modified gravity parameters, such as the GW friction $\alpha_{\rm M}$ and the tensor speed exce...
2212.06082v3
2023-02-01
Post-dynamical inspiral phase of common envelope evolution: Binary orbit evolution and angular momentum transport
After the companion dynamically plunges through the primary's envelope, the two cores remain surrounded by a common envelope and the decrease of the orbital period $P_\text{orb}$ stalls. The subsequent evolution has never been systematically explored with multidimensional simulations. For this study, we performed 3D hy...
2302.00691v2
2023-04-05
Threshold current of field-free perpendicular magnetization switching using anomalous spin-orbit torque
Spin-orbit torque (SOT) is a candidate technique in next generation magnetic random-access memory (MRAM). Recently, experiments show that some material with low-symmetric crystalline or magnetic structures can generate anomalous SOT that has an out-of-plane component, which is crucial in switching perpendicular magneti...
2304.02248v2
2023-04-24
Magnetic levitation by rotation
A permanent magnet can be levitated simply by placing it in the vicinity of another permanent magnet that rotates in the order of 200 Hz. This surprising effect can be easily reproduced in the lab with off-the-shelf components. Here we investigate this novel type of magnetic levitation experimentally and clarify the un...
2305.00812v3
2023-07-26
Formulation and Implementation of Frequency-Dependent Linear Response Properties with Relativistic Coupled Cluster Theory for GPU-accelerated Computer Architectures
We present the development and implementation of the relativistic coupled cluster linear response theory (CC-LR) which allows the determination of molecular properties arising from time-dependent or time-independent electric, magnetic, or mixed electric-magnetic perturbations (within a common gauge origin), and take in...
2307.14296v2
2023-09-22
Challenges in Quasinormal Mode Extraction: Perspectives from Numerical solutions to the Teukolsky Equation
The intricacies of black hole ringdown analysis are amplified by the absence of a complete set of orthogonal basis functions for quasinormal modes. Although damped sinusoids effectively fit the ringdown signals from binary black hole mergers, the risk of overfitting remains, due to initial transients and nonlinear effe...
2309.13204v3
2023-09-25
Influence of density and viscosity on deformation, breakage, and coalescence of bubbles in turbulence
We investigate the effect of density and viscosity differences on a swarm of large and deformable bubbles dispersed in a turbulent channel flow. For a given shear Reynolds number, Re=300, and a constant bubble volume fraction, Phi=5.4%, we perform a campaign of direct numerical simulations of turbulence coupled with a ...
2309.13995v1