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2008-02-14
Influence of an inner disc on the orbital evolution of massive planets migrating in resonance
The formation of resonant pairs of planets in exoplanetary systems involves planetary migration in the protoplanetary disc. After a resonant capture, the subsequent migration in this configuration leads to a large increase of planetary eccentricities if no damping mechanism is applied. This has led to the conclusion th...
0802.2014v1
2008-04-10
Embedded Oscillating Starless Cores
In a previous paper we demonstrated that non-radial hydrodynamic oscillations of a thermally-supported (Bonnor-Ebert) sphere embedded in a low-density, high-temperature medium persist for many periods. The predicted column density variations and molecular spectral line profiles are similar to those observed in the Bok ...
0804.1790v1
2008-05-07
Design of parametrically forced patterns and quasipatterns
The Faraday wave experiment is a classic example of a system driven by parametric forcing, and it produces a wide range of complex patterns, including superlattice patterns and quasipatterns. Nonlinear three-wave interactions between driven and weakly damped modes play a key role in determining which patterns are favou...
0805.0878v1
2008-06-19
Itinerant spin excitations near the hidden order transition in URu2Si2
By means of neutron scattering we show that the high-temperature precursor to the hidden order state of the heavy fermion superconductor URu$_{2}$Si$_{2}$ exhibits heavily damped incommensurate paramagnons whose strong energy dispersion is very similar to that of the long-lived longitudinal f-spin excitations that appe...
0806.3137v2
2008-11-21
Specific heat anomalies of open quantum systems
The evaluation of the specific heat of an open, damped quantum system is a subtle issue. One possible route is based on the thermodynamic partition function which is the ratio of the partition functions of system plus bath and of the bath alone. For the free damped particle it has been shown, however, that the ensuing ...
0811.3509v2
2008-11-26
Three-dimensional simulations of multiple protoplanets embedded in a protostellar disc
Protoplanet eccentricities of e >~ H/r can slow or reverse migration, but previous 2D studies have shown that gravitational scattering cannot maintain significant planet eccentricities against disc-induced damping. We simulate the evolution of low-mass protoplanetary swarms in three dimensions. The aim is to examine bo...
0811.4322v1
2008-12-15
Swift-UVOT captures the earliest ultraviolet spectrum of a Gamma Ray Burst
We present the earliest ever ultraviolet spectrum of a gamma-ray burst (GRB) as observed with the Swift-UVOT. The GRB 081203A spectrum was observed for 50 seconds with the UV grism starting 251 seconds after the Swift-BAT trigger when the GRB was of u ~13.4 mag and still rising to its peak optical brightness. The UV gr...
0812.2943v2
2008-12-16
On the oscillations of dissipative superfluid neutron stars
We investigate the oscillations of slowly rotating superfluid stars, taking into account the vortex mediated mutual friction force that is expected to be the main damping mechanism in mature neutron star cores. Working to linear order in the rotation of the star, we consider both the fundamental f-modes and the inertia...
0812.3023v1
2009-03-27
Cascade and Damping of Alfvén-Cyclotron Fluctuations: Application to Solar Wind Turbulence
It is well-recognized that the presence of magnetic fields will lead to anisotropic energy cascade and dissipation of astrophysical turbulence. With the diffusion approximation and linear dissipation rates, we study the cascade and damping of Alfv\'en-cyclotron fluctuations in solar plasmas numerically. For an isotropi...
0903.4904v1
2009-04-17
Plasmons and polaritons in a semi-infinite plasma and a plasma slab
Plasmon and polariton modes are derived for an ideal semi-infinite (half-space) plasma and an ideal plasma slab by using a general, unifying procedure, based on equations of motion, Maxwell's equations and suitable boundary conditions. Known results are re-obtained in much a more direct manner and new ones are derived....
0904.2662v1
2009-09-30
Dynamic polarization of graphene by moving external charges: random phase approximation
We evaluate the stopping and image forces on a charged particle moving parallel to a doped sheet of graphene by using the dielectric response formalism for graphene's $\pi$-electron bands in the random phase approximation (RPA). The forces are presented as functions of the particle speed and the particle distance for a...
0909.5598v3
2010-02-05
Implementation of an Innovative Bio Inspired GA and PSO Algorithm for Controller design considering Steam GT Dynamics
The Application of Bio Inspired Algorithms to complicated Power System Stability Problems has recently attracted the researchers in the field of Artificial Intelligence. Low frequency oscillations after a disturbance in a Power system, if not sufficiently damped, can drive the system unstable. This paper provides a sys...
1002.1184v1
2010-03-12
Improving the model of emission from spinning dust: effects of grain wobbling and transient spin-up
Observations continue to support the interpretation of the anomalous microwave foreground as electric dipole radiation from spinning dust grains as proposed by Draine and Lazarian (1998ab). In this paper we present a refinement of the original model by improving the treatment of a number of physical effects. First, we ...
1003.2638v2
2010-03-15
Small BGK waves and nonlinear Landau damping
Consider 1D Vlasov-poisson system with a fixed ion background and periodic condition on the space variable. First, we show that for general homogeneous equilibria, within any small neighborhood in the Sobolev space W^{s,p} (p>1,s<1+(1/p)) of the steady distribution function, there exist nontrivial travelling wave solut...
1003.3005v1
2010-04-06
Electronic screening and damping in magnetars
We calculate the screening of the ion-ion potential due to electrons in the presence of a large background magnetic field, at densities of relevance to neutron star crusts. Using the standard approach to incorporate electron screening through the one-loop polarization function, we show that the magnetic field produces ...
1004.0926v1
2010-06-25
Decoherence window and electron-nuclear cross-relaxation in the molecular magnet V 15
Rabi oscillations in the V_15 Single Molecule Magnet (SMM) embedded in the surfactant DODA have been studied at different microwave powers. An intense damping peak is observed when the Rabi frequency Omega_R falls in the vicinity of the Larmor frequency of protons w_N, while the damping time t_R of oscillations reaches...
1006.4960v3
2010-08-31
A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to Damped Lyman-alpha Systems - II. Dynamical Properties of the Galaxies towards Q0302-223 and Q1009-0026
Details of processes through which galaxies convert their gas into stars need to be studied in order to obtain a complete picture of galaxy formation. One way to tackle these phenomena is to relate the HI gas and the stars in galaxies. Here, we present dynamical properties of Damped and sub-Damped Lyman-alpha Systems i...
1009.0027v1
2010-11-10
Standing Slow-Mode Waves in Hot Coronal Loops: Observations, Modeling, and Coronal Seismology
Strongly damped Doppler shift oscillations are observed frequently associated with flarelike events in hot coronal loops. In this paper, a review of the observed properties and the theoretical modeling is presented. Statistical measurements of physical parameters (period, decay time, and amplitude) have been obtained b...
1011.2483v1
2010-11-29
Long-time dynamics of Kirchhoff wave models with strong nonlinear damping
We study well-posedness and long-time dynamics of a class of quasilinear wave equations with a strong damping. We accept the Kirchhoff hypotheses and assume that the stiffness and damping coefficients are $C^1$ functions of the $L_2$-norm of the gradient of the displacement. We first prove the existence and uniqueness ...
1011.6271v3
2010-12-01
Dissipative processes in superfluid neutron stars
We present some results about a novel damping mechanism of r-mode oscillations in neutron stars due to processes that change the number of protons, neutrons and electrons. Deviations from equilibrium of the number densities of the various species lead to the appearance in the Euler equations of the system of a dissipat...
1012.0345v1
2011-01-19
Numerical simulation of fundamental trapped sausage modes
Context: We integrate the 2D MHD ideal equations of a straight slab to simulate observational results associated with fundamental sausage trapped modes. Aims: Starting from a non-equilibrium state with a dense chromospheric layer, we analyse the evolution of the internal plasma dynamics of magnetic loops, subject to li...
1101.3782v1
2011-03-25
Dissipation and Vertical Energy Transport in Radiation-Dominated Accretion Disks
Standard models of radiation supported accretion disks generally assume that diffusive radiation flux is solely responsible for vertical heat transport. This requires that heat must be generated at a critical rate per unit volume if the disk is to be in hydrostatic and thermal equilibrium. This raises the question of h...
1103.5052v1
2011-06-09
Planet-disk interaction in highly inclined systems
We study the interaction of a proto-planetary disk and a planet on a highly inclined orbit in the linear regime. The evolution of the planet is dominated by dynamical friction for planet masses above several Earth-masses. Smaller planets are dominated by aerodynamic drag, especially for very high inclinations and retro...
1106.1869v2
2011-08-16
Brownian force noise from molecular collisions and the sensitivity of advanced gravitational wave observatories
We present an analysis of Brownian force noise from residual gas damping of reference test masses as a fundamental sensitivity limit in small force experiments. The resulting acceleration noise increases significantly when the distance of the test mass to the surrounding experimental apparatus is smaller than the dimen...
1108.3254v2
2011-09-22
Hole spin relaxation and coefficients in Landau-Lifshitz-Gilbert equation in ferromagnetic GaMnAs
We investigate the temperature dependence of the coefficients in the Landau-Lifshitz-Gilbert equation in ferromagnetic GaMnAs by employing the Zener model. We first calculate the hole spin relaxation time based on the microscopic kinetic equation. We find that the hole spin relaxation time is typically several tens fem...
1109.4964v1
2011-09-23
Accretion of Rocky Planets by Hot Jupiters
The observed population of Hot Jupiters displays a stunning variety of physical properties, including a wide range of densities and core sizes for a given planetary mass. Motivated by the observational sample, this paper studies the accretion of rocky planets by Hot Jupiters, after the Jovian planets have finished thei...
1109.5104v1
2011-09-27
Dispersion and damping of zone-boundary magnons in the noncentrosymmetric superconductor CePt3Si
Inelastic neutron scattering (INS) is employed to study damped spin-wave excitations in the noncentrosymmetric heavy-fermion superconductor CePt3Si along the antiferromagnetic Brillouin-zone boundary in the low-temperature magnetically ordered state. Measurements along the (1/2 1/2 L) and (H H 1/2-H) reciprocal-space d...
1109.5784v1
2011-11-15
Spin waves in nanosized magnetic films
We have studied spin excitations in nanosized magnetic films in the Heisenberg model with magnetic dipole and exchange interactions by the spin operator diagram technique. Dispersion relations of spin waves in thin magnetic films (in two-dimensional magnetic monolayers and in two-layer magnetic films) and the spin-wave...
1111.3532v1
2011-12-16
Nonlinear viscous damping and gravitational wave detectability of the f-mode instability in neutron stars
We study the damping of the gravitational radiation-driven f-mode instability in rotating neutron stars by nonlinear bulk viscosity in the so-called supra-thermal regime. In this regime the dissipative action of bulk viscosity is known to be enhanced as a result of nonlinear contributions with respect to the oscillatio...
1112.3931v2
2012-01-23
PageRank and rank-reversal dependence on the damping factor
PageRank (PR) is an algorithm originally developed by Google to evaluate the importance of web pages. Considering how deeply rooted Google's PR algorithm is to gathering relevant information or to the success of modern businesses, the question of rank-stability and choice of the damping factor (a parameter in the algor...
1201.4787v1
2012-02-28
Planetesimal Dynamics in Inclined Binary Systems: The Role of Gas-Disk Gravity
We investigate the effects of gas-disk gravity on the planetesimal dynamics in inclined binary systems, where the circumprimary disk plane is tilted by a significant angle ($i_B$) with respect to the binary disk plane. Our focus is on the Lidov-Kozai mechanism and the evolution of planetesimal eccentricity and inclinat...
1202.6102v1
2012-04-20
The Stability of Massive Main Sequence Stars as a Function of Metallicity
We investigate the pulsational stability of massive (M >~ 120 Msun) main sequence stars of a range of metallicities, including primordial, Population III stars. We include a formulation of convective damping motivated by numerical simulations of the interaction between convection and periodic shear flows. We find that ...
1204.4741v1
2012-05-14
Dynamics of multipartite quantum correlations under decoherence
Quantum discord is an optimal resource for the quantification of classical and non-classical correlations as compared to other related measures. Geometric measure of quantum discord is another measure of quantum correlations. Recently, the geometric quantum discord for multipartite states has been introduced by Jianwei...
1205.3133v1
2012-06-04
In search of random uncorrelated particle motion (RUM) in a simple random flow field
DNS studies of dispersed particle motion in isotropic homogeneous turbulence [1] have revealed the existence of a component of random uncorrelated motion (RUM)dependent on the particle inertia {\tau}p(normalised particle response time or Stoke number). This paper reports the presence of RUM in a simple linear random sm...
1206.0572v1
2012-06-11
Solitons in a parametrically driven damped discrete nonlinear Schrödinger equation
We consider a parametrically driven damped discrete nonlinear Schr\"odinger (PDDNLS) equation. Analytical and numerical calculations are performed to determine the existence and stability of fundamental discrete bright solitons. We show that there are two types of onsite discrete soliton, namely onsite type I and II. W...
1206.2405v1
2012-07-13
Axion as a cold dark matter candidate: low-mass case
Axion as a coherently oscillating scalar field is known to behave as a cold dark matter in all cosmologically relevant scales. For conventional axion mass with 10^{-5} eV, the axion reveals a characteristic damping behavior in the evolution of density perturbations on scales smaller than the solar system size. The damp...
1207.3124v1
2012-09-04
Solving Vlasov Equations Using NRxx Method
In this paper, we propose a moment method to numerically solve the Vlasov equations using the framework of the NRxx method developed in [6, 8, 7] for the Boltzmann equation. Due to the same convection term of the Boltzmann equation and the Vlasov equation, it is very convenient to use the moment expansion in the NRxx m...
1209.0527v1
2012-10-09
A close-pair analysis of damp mergers at intermediate redshifts
We have studied the kinematics of ~2800 candidate close pair galaxies at 0.1<z<1.2 identified from the Canada-France-Hawaii Telescope Legacy Survey fields. Spectra of these systems were obtained using spectrometers on the 6.5m Magellan and 5m Hale telescopes. These data allow us to constrain the rate of dry mergers at ...
1210.2692v1
2012-10-24
Dual Trigger of Transverse Oscillations in a Prominence by EUV Fast and Slow Coronal Waves: SDO/AIA and STEREO/EUVI Observations
We analyze flare-associated transverse oscillations in a quiescent solar prominence on 8-9 September, 2010. Both the flaring active region and the prominence were located near the West limb, with a favorable configuration and viewing angle. The fulldisk extreme ultraviolet (EUV) images of the Sun obtained with high spa...
1210.6690v1
2012-10-25
Molecular dissipation in the nonlinear eddy viscosity in the Navier-Stokes equations: modelling of accretion discs
Physical damping, regarding the nonlinear Navier-Stokes viscous flow dynamics, refers to a tensorial turbulent dissipation term, attributed to adjacent moving macroscopic flow components. Mutual dissipation among these parts of fluid is described by a braking term in the momentum equation together with a heating term i...
1210.6848v3
2012-11-07
Gaussification through decoherence
We investigate the loss of nonclassicality and non-Gaussianity of a single-mode state of the radiation field in contact with a thermal reservoir. The damped density matrix for a Fock-diagonal input is written using the Weyl expansion of the density operator. Analysis of the evolution of the quasiprobability densities r...
1211.1701v3
2013-02-05
Complex fragment emission in low energy light-ion reactions
Inclusive energy spectra of the complex fragments (3 $\leq$ Z $\leq$ 5) emitted in the reactions $^{12}$C (77 MeV)+ $^{28}$Si, $^{11}$B (64 MeV)+ $^{28}$Si and $^{12}$C (73 MeV)+ $^{27}$Al (all having the same excitation energy of $ \sim$ 67 MeV), have been measured in the angular range of 10$^\circ$ $\lesssim \theta_{...
1302.1002v1
2013-02-11
Propagation of Alfvénic Waves From Corona to Chromosphere and Consequences for Solar Flares
How do magnetohydrodynamic waves travel from the fully ionized corona, into and through the underlying partially ionized chromosphere, and what are the consequences for solar flares? To address these questions, we have developed a 2-fluid model (of plasma and neutrals) and used it to perform 1D simulations of Alfv\'en ...
1302.2458v1
2013-02-25
Non-classical Correlations in the Quantum Search Algorithm
Entanglement lies at the heart of quantum mechanics and has no classical analogue. It is central to the speed up achieved by quantum algorithms over their classical counterparts. The Grover's search algorithm is one such algorithm which enables us to achieve a quadratic speed up over any known classical algorithm that ...
1302.6005v1
2013-03-01
Generation of Electrostatic Waves via Parametric Instability and Heating of Solar Corona
In the upper layers of the solar atmosphere the temperature increases sharply. We studied possibility of the transfer of neutrals motion energy into the electrostatic waves.Electrostatic waves could damp in the upper layers of the solar atmosphere and their energy could be transformed into the thermal energy of the sol...
1303.0151v1
2013-03-19
Cosmic Ray Streaming in Clusters of Galaxies
The observed bimodality in radio luminosity in galaxy clusters is puzzling. We investigate the possibility that cosmic-ray (CR) streaming in the intra-cluster medium can 'switch off' hadronically induced radio and gamma-ray emission. For self-confined CRs, this depends on the source of MHD wave damping: if only non-lin...
1303.4746v1
2013-05-13
New features of ion acoustic waves in inhomogeneous and permeating plasmas
It is generally accepted that the ion acoustic (IA) wave in plasmas containing ions and electrons with the same temperature is of minor importance due to strong damping of the wave by hot resonant ions. In this work it will be shown that the IA wave is susceptible to excitation even in plasmas with hot ions when both a...
1305.2739v1
2013-05-15
Beam energy dependence of the viscous damping of anisotropic flow
The flow harmonics $v_{2,3}$ for charged hadrons, are studied for a broad range of centrality selections and beam collision energies in Au+Au ($\sqrt{s_{NN}}= 7.7 - 200$ GeV) and Pb+Pb ($\sqrt{s_{NN}}= 2.76$ TeV) collisions. They validate the characteristic signature expected for the system size dependence of viscous d...
1305.3341v3
2013-07-19
Exact 3D solution for static and damped harmonic response of simply supported general laminates
The state-space method is adapted to obtain three dimensional exact solutions for the static and damped dynamic behaviors of simply supported general laminates. The state-space method is written in a general form that permits to handle both cross-ply and antisymmetric angle-ply laminates. This general form also permits...
1307.5285v2
2013-07-25
Lyman-alpha Heating of Inhomogeneous High-redshift Intergalactic Medium
The intergalactic medium (IGM) prior to the epoch of reionization consists mostly of neutral hydrogen gas. Ly-alpha photons produced by early stars resonantly scatter off hydrogen atoms, causing energy exchange between the radiation field and the gas. This interaction results in moderate heating of the gas due to the r...
1307.6859v2
2013-08-17
Thickness and power dependence of the spin-pumping effect in Y3Fe5O12/Pt heterostructures measured by the inverse spin Hall effect
The dependence of the spin-pumping effect on the yttrium iron garnet (Y3Fe5O12, YIG) thickness detected by the inverse spin Hall effect (ISHE) has been investigated quantitatively. Due to the spin-pumping effect driven by the magnetization precession in the ferrimagnetic insulator YIG film a spin-polarized electron cur...
1308.3787v1
2013-09-13
Analytical and experimental stability investigation of a hardware-in-the-loop satellite docking simulator
The European Proximity Operation Simulator (EPOS) of the DLR-German Aerospace Center is a robotics-based simulator that aims at validating and verifying a satellite docking phase. The generic concept features a robotics tracking system working in closed loop with a force/torque feedback signal. Inherent delays in the t...
1309.3512v1
2013-11-12
Investigation into electron cloud effects in the International Linear Collider positron damping ring
We report modeling results for electron cloud buildup and instability in the International Linear Collider positron damping ring. Updated optics, wiggler magnets, and vacuum chamber designs have recently been developed for the 5 GeV, 3.2-km racetrack layout. An analysis of the synchrotron radiation profile around the r...
1311.2890v4
2013-12-18
The behavior of transverse waves in nonuniform solar flux tubes. II. Implications for coronal loop seismology
Seismology of coronal loops using observations of damped transverse oscillations in combination with results from theoretical models is a tool to indirectly infer physical parameters in the solar atmospheric plasma. Existing seismology schemes based on approximations to the period and damping time of kink oscillations ...
1312.5079v1
2014-01-02
Quasi-Normal Modes for Subtracted Rotating and Magnetised Geometries
We obtain explicit separable solutions of the wave equation of massless minimally coupled scalar fields in the subtracted geometry of four-dimensional rotating and Melvin (magnetised) four-charge black holes of the STU model, a consistent truncation of maximally supersymmetric supergravity with four types of electromag...
1401.0544v3
2014-03-12
Enhancing robustness of multiparty quantum correlations using weak measurement
Multipartite quantum correlations are important resources for the development of quantum information and computation protocols. However, the resourcefulness of multipartite quantum correlations in practical settings is limited by its fragility under decoherence due to environmental interactions. Though there exist prot...
1403.2939v1
2014-04-11
Functional Regression for Quasar Spectra
The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light spectrum can be modeled as a noisy realization of a smooth curve that is affected by a ...
1404.3168v1
2014-06-04
Constraints on the gas masses of low-z damped Lyman-$α$ systems
We report a deep search for redshifted HI 21 cm emission from three damped and sub-damped Lyman-$\alpha$ absorbers (DLAs) at $z \approx 0.1$ with the Green Bank Telescope (GBT). No evidence for a redshifted HI 21 cm emission signal was obtained in the GBT spectra of two absorbers, with the data on the third rendered un...
1406.0991v2
2014-06-09
Evolution of eccentricity and orbital inclination of migrating planets in 2:1 mean motion resonance
We determine, analytically and numerically, the conditions needed for a system of two migrating planets trapped in a 2:1 mean motion resonance to enter an inclination-type resonance. We provide an expression for the asymptotic equilibrium value that the eccentricity $e_{\rm i}$ of the inner planet reaches under the com...
1406.2189v1
2014-06-13
Magnetic-Field Amplification in the Thin X-ray Rims of SN1006
Several young supernova remnants (SNRs), including SN1006, emit synchrotron X-rays in narrow filaments, hereafter thin rims, along their periphery. The widths of these rims imply 50 to 100 $\mu$G fields in the region immediately behind the shock, far larger than expected for the interstellar medium compressed by unmodi...
1406.3630v2
2014-07-02
Spin Waves in Ferromagnetic Insulators Coupled via a Normal Metal
Herein, we study the spin-wave dispersion and dissipation in a ferromagnetic insulator--normal metal--ferromagnetic insulator system. Long-range dynamic coupling because of spin pumping and spin transfer lead to collective magnetic excitations in the two thin-film ferromagnets. In addition, the dynamic dipolar field co...
1407.0635v1
2014-07-15
C$ν$B damping of primordial gravitational waves and the fine-tuning of the C$γ$B temperature anisotropy
Damping of primordial gravitational waves due to the anisotropic stress contribution owing to the cosmological neutrino background (C$\nu$B) is investigated in the context of a radiation-to-matter dominated Universe. Besides its inherent effects on the gravitational wave propagation, the inclusion of the C$\nu$B anisot...
1407.4058v1
2014-08-08
Stable Magnetic Droplet Solitons in Spin Transfer Nanocontacts
Magnetic thin films with perpendicular magnetic anisotropy (PMA) have localized excitations that correspond to reversed dynamically precessing magnetic moments, known as magnetic droplet solitons. Fundamentally, these excitations are associated with an attractive interaction between elementary spin-excitations (i.e., m...
1408.1902v1
2014-08-19
Probing Electron Interactions in a Two-Dimensional System by Quantum Magneto-Oscillations
We have experimentally studied the renormalized effective mass m* and Dingle temperature T_D in two spin subbands with essentially different electron populations. Firstly, we found that the product (m*T_D) that determines damping of quantum oscillations, to the first approximation, is the same in the majority and minor...
1408.4393v1
2014-09-30
Collective modes in two- and three-dimensional electron systems with Rashba spin-orbit coupling
In addition to charge plasmons, a 2D electron system with Rashba-type spin-orbit coupling (SOC) also supports three collective modes in the spin sector: the chiral-spin modes. We study the dispersions of the charge and spin modes and their coupling to each other within a generalized Random Phase Approximation for arbit...
1409.8666v1
2014-11-15
Spin-transfer-torque through antiferromagnetic IrMn
Spin-transfer-torque, a transfer of angular momentum between the electron spin and the local magnetic moments, is a promising and key mechanism to control ferromagnetic materials in modern spintronic devices . However, much less attention has been paid to the same effect in antiferromagnets. For the sake of investigati...
1411.4100v4
2014-11-28
On damped second-order gradient systems
Using small deformations of the total energy, as introduced in [31], we establish that damped second order gradient systems $$u^{\prime\prime}(t)+\gamma u^\prime(t)+\nabla G(u(t))=0,$$may be viewed as quasi-gradient systems. In order to study the asymptotic behavior of these systems, we prove that any (nontrivial) desi...
1411.8005v5
2014-12-08
Variable frequency characterization of interaction at nanoscale in linear dynamic AFM: an FFM primer
Using electrostatic coupling between an AFM tip and a metallic surface as a test interaction, we here present the measurement of the force between the tip and the surface, together with the measurement of the interaction stiffness and the associated dissipation. These three quantities constitute a full characterization...
1412.2640v1
2015-01-12
Standing Slow MHD Waves in Radiatively Cooling Coronal Loops
The standing slow magneto-acoustic oscillations in cooling coronal loops are investigated. There are two damping mechanisms which are considered to generate the standing acoustic modes in coronal magnetic loops namely thermal conduction and radiation. The background temperature is assumed to change temporally due to op...
1501.02689v1
2015-01-12
Beta decay of 252Cf on the way to scission from the exit point
Upon increasing significantly the nuclear elongation, the beta-decay energy grows. This paper investigates within a simple yet partly microscopic approach, the transition rate of the beta decay of the 252Cf nucleus on the way to scission from the exit point for a spontaneous fission process. A rather crude classical ap...
1501.02701v1
2015-01-13
Fundamental oscillation modes of neutron stars: validity of universal relations
We study the $f$-mode frequencies and damping times of nonrotating neutron stars (NS) in general relativity (GR) by solving the linearized perturbation equations, with the aim to establish "universal" relations that depend only weakly on the equations of state (EOS). Using a more comprehensive set of EOSs, we re-examin...
1501.02970v2
2015-02-13
Magnetohydrodynamic kink waves in nonuniform solar flux tubes: phase mixing and energy cascade to small scales
Magnetohydrodynamic (MHD) kink waves are ubiquitously observed in the solar atmosphere. The propagation and damping of these waves may play relevant roles for the transport and dissipation of energy in the solar atmospheric medium. However, in the atmospheric plasma dissipation of transverse MHD wave energy by viscosit...
1502.03949v1
2015-03-25
Wave Propagation at Oblique Shocks: How Did Tycho Get Its Stripes?
We describe a new model for the "stripes" of synchrotron radiation seen in the remnant of Tycho's supernova. In our picture, cosmic rays streaming ahead of the forward shock generate parallel (with respect to the local magnetic field direction) circularly polarized Alfven waves that are almost free of dissipation, and ...
1503.07497v1
2015-03-30
Superradiance and instability of small rotating charged AdS black holes in all dimensions
Rotating small AdS black holes exhibit the superradiant instability to low-frequency scalar perturbations, which is amenable to a complete analytic description in four dimensions. In this paper, we extend this description to all higher dimensions, focusing on slowly rotating charged AdS black holes with a single angula...
1503.08607v2
2015-04-12
Evolution of Kinetic and Magnetic Energy in Intra Cluster Media
Intra Cluster Media (ICMs) located at galaxy clusters is in the state of hot, tenuous, magnetized, and highly ionized X-ray emitting plasmas. This overall collisionless, viscous, and conductive magnetohydrodynamic (MHD) turbulence in ICM is simulated using hyper and physical magnetic diffusivity. The results show that ...
1504.02940v3
2015-04-17
Effective Action for Cosmological Scalar Fields at Finite Temperature
Scalar fields appear in many theories beyond the Standard Model of particle physics. In the early universe, they are exposed to extreme conditions, including high temperature and rapid cosmic expansion. Understanding their behavior in this environment is crucial to understand the implications for cosmology. We calculat...
1504.04444v2
2015-05-19
The elusive HI-> H2 transition in high-z damped Lyman-alpha systems
We study the H2 molecular content in high redshift damped Lyman-alpha systems (DLAs) as a function of the HI column density. We find a significant increase of the H2 molecular content around log N(HI) (cm^-2)~21.5-22, a regime unprobed until now in intervening DLAs, beyond which the majority of systems have log N(H2) >...
1505.04997v1
2015-06-11
Dynamics near the subcritical transition of the 3D Couette flow I: Below threshold case
We study small disturbances to the periodic, plane Couette flow in the 3D incompressible Navier-Stokes equations at high Reynolds number $\textbf{Re}$. We prove that for sufficiently regular initial data of size $\epsilon \leq c_0\textbf{Re}^{-1}$ for some universal $c_0 > 0$, the solution is global, remains within $O(...
1506.03720v1
2015-06-12
Casimir Friction Between Polarizable Particle and Half-Space with Radiation Damping and Image Damping at Zero Temperature
Casimir friction between a polarizable particle and a semi-infinite space is a delicate physical phenomenon, as it concerns the interaction between a microscopic quantum particle and a semi-infinite reservoir. Not unexpectedly, results obtained in the past about the friction force obtained via different routes are some...
1506.03937v2
2015-07-08
Periods and damping rates of fast sausage oscillations in multi-shelled coronal loops
Standing sausage modes are important in interpreting quasi-periodic pulsations in the lightcurves of solar flares. Their periods and damping times play an important role in seismologically diagnosing key parameters like the magnetic field strength in regions where flare energy is released. Usually such applications are...
1507.02169v1
2015-07-23
Asteroseismology of rapidly rotating neutron stars - an alternative approach
In the present paper we examine gravitational wave asteroseismology relations for f-modes of rapidly rotating neutron stars. An approach different to the previous studies is employed - first, the moment of inertia is used instead of the stellar radius, and second, the normalization of the oscillation frequencies and da...
1507.06606v1
2015-07-31
Eccentricity Evolution Through Accretion of Protoplanets
Most of super-Earths detected by the radial velocity (RV) method have significantly smaller eccentricities than the eccentricities corresponding to velocity dispersion equal to their surface escape velocity ("escape eccentricities"). If orbital instability followed by giant impacts among protoplanets that have migrated...
1507.08809v1
2015-08-25
Effects of inertia on the steady-shear rheology of disordered solids
We study the finite-shear-rate rheology of disordered solids by means of molecular dynamics simulations in two dimensions. By systematically varying the damping magnitude $\zeta$ in the low-temperature limit, we identify two well defined flow regimes, separated by a thin (temperature-dependent) crossover region. In the...
1508.06067v3
2015-09-01
Persistence of a Non-Equilibrium State: Observation of a Boltzmannian Special Case
Well before the atomistic nature of matter was experimentally established, Ludwig Boltzmann's audacious effort to explain the macroscopic world of human experience in terms of the workings of an unseen microscopic world met with vigorous opposition. A contentious point was the problem of irreversibility: the microscopi...
1509.00366v1
2015-09-14
Nonlinear Energetic Particle Transport in the Presence of Multiple Alfvenic Waves in ITER
This work presents the results of a multi mode ITER study on Toroidal Alfven Eigenmodes, using the nonlinear hybrid HAGIS-LIGKA model. It is found that main conclusions from earlier studies of ASDEX Upgrade discharges can be transferred to the ITER scenario: global, nonlinear effects are crucial for the evolution of th...
1509.04010v1
2015-09-30
Dynamic Quantum Tomography Model for Phase-Damping Channels
In this article we propose a dynamic quantum tomography model for open quantum systems with evolution given by phase-damping channels. Mathematically, these channels correspond to completely positive trace-preserving maps defined by the Hadamard product of the initial density matrix with a time-dependent matrix which c...
1509.09318v3
2015-10-24
Propagation of GeV neutrinos through Earth
We have studied the Earth matter effect on the oscillation of upward going GeV neutrinos by taking into account the three active neutrino flavors. For neutrino energy in the range 3 to 12 GeV we observed three distinct resonant peaks for the oscillation process $\nu_e\leftrightarrow \nu_{\mu,\tau}$ in three \textit{dis...
1510.07103v2
2015-11-18
Surface waves propagation on a turbulent flow forced electromagnetically
We study the propagation of monochromatic surface waves on a turbulent flow. The flow is generated in a layer of liquid metal by an electromagnetic forcing. This forcing creates a quasi two-dimensional (2D) turbulence with strong vertical vorticity. The turbulent flow contains much more energy than the surface waves. I...
1511.05900v1
2015-12-15
Correlations between compositions and orbits established by the giant impact era of planet formation
The giant impact phase of terrestrial planet formation establishes connections between super-Earths' orbital properties (semimajor axis spacings, eccentricities, mutual inclinations) and interior compositions (the presence or absence of gaseous envelopes). Using N-body simulations and analytic arguments, we show that s...
1512.04951v2
2015-12-18
Seismic waves damping with arrays of inertial resonators
We investigate the elastic stop band properties of a theoretical cubic array of iron spheres connected to a bulk of concrete via iron or rubber ligaments. Each sphere can move freely within a surrounding air cavity, but ligaments couple it to the bulk and further facilitate bending and rotational motions. Associated lo...
1512.06078v2
2016-01-08
Kinetic Simulation of Slow Magnetosonic Waves and Quasi-periodic Upflows in the Solar Corona
Quasi-periodic disturbances of emission-line parameters are frequently observed in the corona. These disturbances propagate upward along the magnetic field with speeds $\sim100~\rm{km~s}^{-1}$. This phenomenon has been interpreted as evidence of the propagation of slow magnetosonic waves or argued to be signature of th...
1601.01823v1
2016-01-25
Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario
The linear stability of Alfv\'en eigenmodes in the presence of fusion-born alpha particles is thoroughly assessed for two variants of an ITER baseline scenario, which differ significantly in their core and pedestal temperatures. A systematic approach is used that considers all possible eigenmodes for a given magnetic e...
1601.06621v1
2016-01-27
Flash ionisation signature in coherent cyclotron emission from Brown Dwarfs
Brown dwarfs form mineral clouds in their atmospheres, where charged particles can produce large-scale discharges in form of lightning resulting in a substantial sudden increase of local ionisation. Brown dwarfs are observed to emit cyclotron radio emission. We show that signatures of strong transient atmospheric ionis...
1601.07474v1
2016-02-02
Sudden-quench dynamics of Bardeen-Cooper-Schrieffer states in deep optical lattices
We determine the exact dynamics of an initial Bardeen-Cooper-Schrieffer (BCS) state of ultra-cold atoms in a deep hexagonal optical lattice. The dynamical evolution is triggered by a quench of the lattice potential, such that the interaction strength $U_f$ is much larger than the hopping amplitude $J_f$. The quench ini...
1602.00979v2
2016-03-09
Conclusive Identification of Quantum Channels via Monogamy of Quantum Correlations
We investigate the action of local and global noise on monogamy of quantum correlations, when monogamy scores are considered as observables, and three-qubit systems are subjected to global noise and various local noisy channels, namely, amplitude-damping, phase-damping, and depolarizing channels. We show that the dynam...
1603.02801v3
2016-05-05
Electromagnetic fields in the exterior of an oscillating relativistic star -- II. Electromagnetic damping
An important issue in the asteroseismology of compact and magnetized stars is the determination of the dissipation mechanism which is most efficient in damping the oscillations when these are produced. In a linear regime and for low-multipolarity modes these mechanisms are confined to either gravitational-wave or elect...
1605.01709v1
2016-05-22
Low Gilbert damping in Co2FeSi and Fe2CoSi films
Thin highly textured Fe$_{\mathrm{1+x}}$Co$_{\mathrm{2-x}}$Si ($0 \leq$ x $\leq 1$) films were prepared on MgO (001) substrates by magnetron co-sputtering. The magneto-optic Kerr effect (MOKE) and ferromagnetic resonance (FMR) measurements were used to investigate the composition dependence of the magnetization, the ma...
1605.06797v1
2016-06-14
Landau damping to partially locked states in the Kuramoto model
In the Kuramoto model of globally coupled oscillators, partially locked states (PLS) are stationary solutions that incorporate the emergence of partial synchrony when the interaction strength increases. While PLS have long been considered, existing results on their stability are limited to neutral stability of the line...
1606.04470v1
2016-07-20
Electromagnon in the Z-type hexaferrite $({\rm Ba}_{x}{\rm Sr}_{1-x})_3\rm Co_2Fe_{24}O_{41}$
We studied experimentally the high-temperature magnetoelectric $({\rm Ba}_{x}{\rm Sr}_{1-x})_3\rm Co_2Fe_{24}O_{41}$ prepared as ceramics (x = 0, 0.2) and a single crystal (x = 0.5) using inelastic neutron scattering, THz time-domain, Raman and far-infrared spectroscopies. The spectra, measured with varying temperature...
1607.05878v1
2016-07-28
Damping of the Milky Way bar by manifold-driven spirals
We describe a new phenomenon of `bar damping' that may have played an important role in shaping the Milky Way bar and bulge as well as its spiral structure. We use a collisionless N-body simulation of a Milky Way-like galaxy initially composed of a dark matter halo and an exponential disk with Toomre parameter slightly...
1607.08339v2