publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
|---|---|---|---|
2020-05-11 | Manipulating 1-dimensinal skyrmion motion by external magnetic field gradient | We have investigated an analytic formula of the 1-dimensional magnetic
skyrmion dynamics under external magnetic field gradient. We find excellent
agreement between the analytical model and micromagnetic simulation results for
various magnetic parameters such as the magnetic field gradient, Gilbert
damping constant. We... | 2005.05011v1 |
2020-06-28 | Physical pendulum model: Fractional differential equation and memory effects | A detailed analysis of three pendular motion models is presented. Inertial
effects, self-oscillation, and memory, together with non-constant moment of
inertia, hysteresis and negative damping are shown to be required for the
comprehensive description of the free pendulum oscillatory regime. The effects
of very high ini... | 2006.15665v3 |
2020-08-01 | Equilibration of the chiral asymmetry due to finite electron mass in electron-positron plasma | We calculate the rate of collisional decay of the axial charge in an
ultrarelativistic electron-positron plasma, also known as the chirality
flipping rate. We find that contrary to the existing estimates, the chirality
flipping rate appears already in the first order in the fine-structure constant
$\alpha$ and is there... | 2008.00360v2 |
2020-08-12 | Effective Field Theory for Quasicrystals and Phasons Dynamics | We build an effective field theory (EFT) for quasicrystals -- aperiodic
incommensurate lattice structures -- at finite temperature, entirely based on
symmetry arguments and a well-define action principle. By means of
Schwinger-Keldysh techniques, we derive the full dissipative dynamics of the
system and we recover the ... | 2008.05339v2 |
2020-08-18 | Research on rolling friction's dependence on ball bearings' radius | There are two alternative historical laws of rolling resistance formulated by
French scientist Coulomb and Dupuit. It has been decided to verify
experimentally again, which of these laws describes freely rolling ball
bearings on a hard surface better. An inducement to carrying out the
measurements was the idea of the c... | 2008.08127v1 |
2020-08-28 | Finding Small and Large k-Clique Instances on a Quantum Computer | Algorithms for triangle-finding, the smallest nontrivial instance of the
k-clique problem, have been proposed for quantum computers. Still, those
algorithms assume the use of fixed access time quantum RAM (QRAM). We present a
practical gate-based approach to both the triangle-finding problem and its
NP-hard k-clique ge... | 2008.12525v1 |
2020-09-02 | Frustrated bearings | In a bearing state, touching spheres (disks in two dimensions) roll on each
other without slip. Here we frustrate a system of touching spheres by imposing
two different bearing states on opposite sides and search for the
configurations of lowest energy dissipation. If the dissipation between
contacts of spheres is visc... | 2009.01295v1 |
2020-09-04 | Scalar Perturbations of a Single-Horizon Regular Black Hole | We investigate the massless scalar field perturbations, including the
quasinormal mode spectrum and the ringdown waveform, of a regular black hole
spacetime that was derived via the Loop Quantum Gravity inspired polymer
quantization of spherical $4$D black holes. In contrast to most, if not all, of
the other regular bl... | 2009.02367v2 |
2020-09-22 | Quasinormal modes of dirty black holes in the two-loop renormalizable effective gravity | We consider gravitational quasinormal modes of the static and
spherically-symmetric dirty black holes in the effective theory of gravity
which is renormalizable at the two-loop level. It is demonstrated that using
the WKB-Pad\'e summation proposed in \cite{jaOp} one can achieve sufficient
accuracy to calculate correcti... | 2009.10793v1 |
2020-10-04 | On the interaction problem between a compressible viscous fluid and a nonlinear thermoelastic plate | In this paper we study the interaction problem between a nonlinear
thermoelastic plate and a compressible viscous fluid with the adiabatic
constant $\gamma>12/7$. The existence of a weak solution for this problem is
obtained by constructing a time-continuous operator splitting scheme that
decouples the fluid and the st... | 2010.01639v1 |
2020-10-08 | On the cost of Bayesian posterior mean strategy for log-concave models | In this paper, we investigate the problem of computing Bayesian estimators
using Langevin Monte-Carlo type approximation. The novelty of this paper is to
consider together the statistical and numerical counterparts (in a general
log-concave setting). More precisely, we address the following question: given
$n$ observat... | 2010.06420v2 |
2020-10-28 | Tunable plasmon modes in doped AA-stacked bilayer graphene | We study plasmon modes in doped AA-stacked bilayer graphene (BLG) within the
nearest-neighbor tight-binding and the random phase approximation. We obtain
closed analytical expressions for the polarizability function which are used to
obtain the low-energy dispersion relations of and the numerical results for
both acous... | 2010.14999v3 |
2020-11-04 | EAdam Optimizer: How $ε$ Impact Adam | Many adaptive optimization methods have been proposed and used in deep
learning, in which Adam is regarded as the default algorithm and widely used in
many deep learning frameworks. Recently, many variants of Adam, such as
Adabound, RAdam and Adabelief, have been proposed and show better performance
than Adam. However,... | 2011.02150v1 |
2020-11-16 | Quantum Analysis of BTZ Black Hole Formation Due to the Collapse of a Dust Shell | We perform Hamiltonian reduction of a model in which 2+1 dimensional gravity
with negative cosmological constant is coupled to a cylindrically symmetric
dust shell. The resulting action contains only a finite number of degrees of
freedom. The phase space consists of two copies of $ADS^2$ -- both coordinate
and momentum... | 2011.07971v2 |
2020-11-23 | Energy decay rates of solutions to a viscoelastic wave equation with variable exponents and weak damping | The goal of the present paper is to study the asymptotic behavior of
solutions for the viscoelastic wave equation with variable exponents \[
u_{tt}-\Delta u+\int_0^tg(t-s)\Delta u(s)ds+a|u_t|^{m(x)-2}u_t=b|u|^{p(x)-2}u\]
under initial-boundary condition, where the exponents $p(x)$ and $m(x)$ are
given functions, and $a... | 2011.11185v1 |
2020-11-27 | Eigenvalue-corrected Natural Gradient Based on a New Approximation | Using second-order optimization methods for training deep neural networks
(DNNs) has attracted many researchers. A recently proposed method,
Eigenvalue-corrected Kronecker Factorization (EKFAC) (George et al., 2018),
proposes an interpretation of viewing natural gradient update as a diagonal
method, and corrects the in... | 2011.13609v1 |
2020-12-12 | Stabilized explicit Adams-type methods | In this work we present explicit Adams-type multistep methods with extended
stability interval, which are analogous to the stabilized Chebyshev
Runge--Kutta methods. It is proved that for any $k\geq 1$ there exists an
explicit $k$-step Adams-type method of order one with stability interval of
length $2k$. The first ord... | 2012.06767v1 |
2020-12-18 | Quantum friction in the Hydrodynamic Model | We study the phenomenon of quantum friction in a system consisting of a
polarizable atom moving at a constant speed parallel to a metallic plate. The
metal is described using a charged hydrodynamic model for the electrons. This
model featuring long-range interactions is appropriate for a clean metal in a
temperature ra... | 2012.10204v1 |
2020-12-20 | A new model with solitary waves: solution, stability and quasinormal modes | We construct solitary wave solutions in a $1+1$ dimensional massless scalar
($\phi$) field theory with a specially chosen potential $V(\phi)$. The equation
governing perturbations about this solitary wave has an effective potential
which is a simple harmonic well over a region, and a constant beyond. This
feature allow... | 2012.10967v2 |
2020-12-29 | Strongly modulated ultrafast demagnetization and magnetization precession dynamics in ferrimagnetic Gdx(CoFe)1-x alloys via 3d-4f intersublattice exchange coupling | Manipulation of the intersublattice interaction strengh (JRE-TM) in rare
earth (RE)-transition metal (TM) alloys is a key issue to understand how
efficiently the laser-induced angular momentum transfers from 3d to 4f spins
and to have a better control of the ultrafast spin dynamics. In this work, the
relationships betw... | 2012.14620v1 |
2021-02-01 | Contour Dynamics for One-Dimensional Vlasov-Poisson Plasma with the Periodic Boundary | We revisit the contour dynamics (CD) simulation method which is applicable to
large deformation of distribution function in the Vlasov-Poisson plasma with
the periodic boundary, where contours of distribution function are traced
without using spatial grids. Novelty of this study lies in application of CD to
the one-dim... | 2102.00866v1 |
2021-02-01 | Strong coupling of Fe-Co alloy with ultralow damping to superconducting co-planar waveguide resonators | We report on the strong coupling between a metallic ferromagnetic Fe75Co25
thin film patterned element and a range of superconducting Nb half-wavelength
co-planar waveguide (CPW) resonators. By varying the volume of the ferromagnet
we demonstrate that the coupling rate scales linearly with the square root of
the number... | 2102.01129v1 |
2021-02-15 | Magnetodynamic properties of dipole-coupled 1D magnonic crystals | Magnonic crystals are magnetic metamaterials, that provide a promising way to
manipulate magnetodynamic properties by controlling the geometry of the
patterned structures. Here, we study the magnetodynamic properties of 1D
magnonic crystals consisting of parallel NiFe strips with different strip
widths and separations.... | 2102.07712v2 |
2021-03-11 | The Debye Length and the Running Coupling of QCD: a Potential and Phenomenological Approach | In this paper, one uses a damped potential to present a description of the
running coupling constant of QCD in the confinement phase. Based on a
phenomenological perspective for the Debye screening length, one compares the
running coupling obtained here with both the Brodsky-de T\'eramond-Deur and the
Richardson approa... | 2103.06642v2 |
2021-03-16 | Adapted gauge to small mass ratio binary black hole evolutions | We explore the benefits of adapted gauges to small mass ratio binary black
hole evolutions in the moving puncture formulation. We find expressions that
approximate the late time behavior of the lapse and shift,
$(\alpha_0,\beta_0)$, and use them as initial values for their evolutions. We
also use a position and black h... | 2103.09326v1 |
2021-03-24 | "Second-Order Primal'' + "First-Order Dual'' Dynamical Systems with Time Scaling for Linear Equality Constrained Convex Optimization Problems | Second-order dynamical systems are important tools for solving optimization
problems, and most of existing works in this field have focused on
unconstrained optimization problems. In this paper, we propose an inertial
primal-dual dynamical system with constant viscous damping and time scaling for
the linear equality co... | 2103.12931v3 |
2021-04-15 | Evolution of Anti-de Sitter black holes in Einstein-Maxwell-dilaton theory | We study the nonlinear evolution of the spherical symmetric black holes under
a small neutral scalar field perturbation in Einstein-Maxwell-dilaton theory
with coupling function $f(\phi)=e^{-b\phi}$ in asymptotic anti-de Sitter
spacetime. The non-minimal coupling between scalar and Maxwell fields allows
the transmissio... | 2104.07281v1 |
2021-04-23 | Well-posedness of a nonlinear shallow water model for an oscillating water column with time-dependent air pressure | We propose in this paper a new nonlinear mathematical model of an oscillating
water column (OWC). The one-dimensional shallow water equations in the presence
of this device is reformulated as a transmission problem related to the
interaction between waves and a fixed partially-immersed structure. By imposing
the conser... | 2104.11570v3 |
2021-04-27 | Green's functions and the Cauchy problem of the Burgers hierarchy and forced Burgers equation | We consider the Cauchy problem for the Burgers hierarchy with general time
dependent coefficients. The closed form for the Green's function of the
corresponding linear equation of arbitrary order $N$ is shown to be a sum of
generalised hypergeometric functions. For suitably damped initial conditions we
plot the time de... | 2104.12976v1 |
2021-05-16 | Time-dependent conformal transformations and the propagator for quadratic systems | The method proposed by Inomata and his collaborators allows us to transform a
damped Caldiroli-Kanai oscillator with time-dependent frequency to one with
constant frequency and no friction by redefining the time variable, obtained by
solving a Ermakov-Milne-Pinney equation. Their mapping ``Eisenhart-Duval''
lifts as a ... | 2105.07374v4 |
2021-06-21 | Universal many-body diffusion from momentum dephasing | The open dynamics of quantum many-body systems involve not only the exchange
of energy, but also of other conserved quantities, such as momentum. This leads
to additional decoherence, which may have a profound impact in the dynamics.
Motivated by this, we consider a many-body system subject to total momentum
dephasing ... | 2106.10984v1 |
2021-06-23 | The MGT-Fourier model in the supercritical case | We address the energy transfer in the differential system $$ \begin{cases}
u_{ttt}+\alpha u_{tt} - \beta \Delta u_t - \gamma \Delta u = -\eta \Delta
\theta \\ \theta_t - \kappa \Delta \theta =\eta \Delta u_{tt}+ \alpha\eta
\Delta u_t \end{cases} $$ made by a Moore-Gibson-Thompson equation in the
supercritical regime, h... | 2106.12402v2 |
2021-07-07 | Amplification of light scattering in arrays of nanoholes by plasmonic absorption-induced transparency | Absorption induced transparency is an optical phenomenon that occurs in
metallic arrays of nanoholes when materials featuring narrow lines in their
absorption spectra are deposited on top of it. First reported in the visible
range, using dye lasers as cover materials, it has been described as
transmission peaks unexpec... | 2107.03135v1 |
2021-08-26 | The Anomalous Transport of Tracers in Active Baths | We derive the long-time dynamics of a tracer immersed in a one-dimensional
active bath. In contrast to previous studies, we find that the damping and
noise correlations possess long-time tails with exponents that depend on the
tracer symmetry. For generic tracers, shape asymmetry induces ratchet effects
that alter fluc... | 2108.11970v3 |
2021-09-23 | Constraining Time Dependent Dark Matter Signals from the Sun | Dark matter (DM) particles captured by the Sun can produce high energy
electrons outside the Sun through annihilating into meta-stable mediators. The
corresponding cosmic-ray electron signals observed by the space-based
experiments will be time dependent due to the orbital motion of the space-based
detectors. The shape... | 2109.11662v3 |
2021-11-01 | Magnon-driven dynamics of frustrated skyrmion in synthetic antiferromagnets: Effect of skyrmion precession | A theoretical study on the interplay of frustrated skyrmion and magnons is
useful for revealing new physics and future experiments design. In this work,
we investigated the magnon-driven dynamics of frustrated skyrmion in synthetic
antiferromagnets, focusing on the effect of skyrmion precession. It is
theoretically rev... | 2111.00738v1 |
2021-11-01 | Safe Online Gain Optimization for Variable Impedance Control | Smooth behaviors are preferable for many contact-rich manipulation tasks.
Impedance control arises as an effective way to regulate robot movements by
mimicking a mass-spring-damping system. Consequently, the robot behavior can be
determined by the impedance gains. However, tuning the impedance gains for
different tasks... | 2111.01258v1 |
2021-11-15 | Extremely confined gap plasmon modes: when nonlocality matters | Historically, the field of plasmonics has been relying on the framework of
classical electrodynamics, with the local-response approximation of material
response being applied even when dealing with nanoscale metallic structures.
However, when approaching the atomic-scale confinement of the electromagnetic
radiation, me... | 2111.07561v1 |
2021-11-16 | Flow around topological defects in active nematic films | We study the active flow around isolated defects and the self-propulsion
velocity of $+1/2$ defects in an active nematic film with both viscous
dissipation (with viscosity $\eta$) and frictional damping $\Gamma$ with a
substrate. The interplay between these two dissipation mechanisms is controlled
by the hydrodynamic d... | 2111.08537v2 |
2021-12-01 | Axial perturbations of hairy Gauss-Bonnet black holes with massive self-interacting scalar field | We study the axial quasinormal modes of hairy black holes in Gauss-Bonnet
gravity with massive self-interacting scalar field. Two coupling functions of
the scalar field to the Gauss-Bonnet invariant are adopted with one of them
leading to black hole scalarization. The axial perturbations are studied via
time evolution ... | 2112.00703v1 |
2021-12-20 | Adversarially Robust Stability Certificates can be Sample-Efficient | Motivated by bridging the simulation to reality gap in the context of
safety-critical systems, we consider learning adversarially robust stability
certificates for unknown nonlinear dynamical systems. In line with approaches
from robust control, we consider additive and Lipschitz bounded adversaries
that perturb the sy... | 2112.10690v1 |
2022-02-10 | Amplifying spin waves along Néel domain wall by spin-orbit torque | Traveling spin waves in magnonic waveguides undergo severe attenuation, which
tends to result in a finite propagation length of spin waves, even in magnetic
materials with the accessible lowest damping constant, heavily restricting the
development of magnonic devices. Compared with the spin waves in traditional
wavegui... | 2202.05181v1 |
2022-03-06 | Elongated Skyrmion as Spin Torque Nano-Oscillator and Magnonic Waveguide | Spin torque nano-oscillator has been extensively studied both theoretically
and experimentally in recent decades due to its potential applications in
future microwave communication technology and neuromorphic computing. In this
work, we present a skyrmion-based spin torque nano-oscillator driven by a
spatially uniform ... | 2203.02969v2 |
2022-03-11 | Absence of Walker breakdown in the dynamics of chiral Neel domain walls driven by in-plane strain gradients | We investigate theoretically the motion of chiral N\'eel domain walls in
perpendicularly magnetized systems driven by in-plane strain gradients. We show
that such strain drives domain walls efficiently towards increasing tensile
(compressive) strain for positive (negative) magnetostrictive materials. During
their motio... | 2203.05826v1 |
2022-06-28 | Origin of the spontaneous oscillations in a simplified coagulation-fragmentation system driven by a source | We consider a system of aggregated clusters of particles, subjected to
coagulation and fragmentation processes with mass dependent rates. Each monomer
particle can aggregate with larger clusters, and each cluster can fragment into
individual monomers with a rate directly proportional to the aggregation rate.
The dynami... | 2206.13884v1 |
2022-06-29 | Strongly coupled quantum Otto cycle with single qubit bath | We discuss a model of a closed quantum evolution of two-qubits where the
joint Hamiltonian is so chosen that one of the qubits acts as a bath and
thermalize the other qubit which is acting as the system. The corresponding
exact master equation for the system is derived. Interestingly, for a specific
choice of parameter... | 2206.14751v1 |
2022-07-24 | Revisiting the central limit theorems for the SGD-type methods | We revisited the central limit theorem (CLT) for stochastic gradient descent
(SGD) type methods, including the vanilla SGD, momentum SGD and Nesterov
accelerated SGD methods with constant or vanishing damping parameters. By
taking advantage of Lyapunov function technique and $L^p$ bound estimates, we
established the CL... | 2207.11755v3 |
2022-08-09 | Parameter Estimation in Ill-conditioned Low-inertia Power Systems | This paper examines model parameter estimation in dynamic power systems whose
governing electro-mechanical equations are ill-conditioned or singular. This
ill-conditioning is because of converter-interfaced power systems generators'
zero or small inertia contribution. Consequently, the overall system inertia
decreases,... | 2208.04471v1 |
2022-08-09 | Driven particle dispersion in narrow disordered racetracks | We study the disorder-induced deterministic dispersion of particles uniformly
driven in an array of narrow tracks. For different toy models with quenched
disorder we obtain exact analytical expressions for the steady-state mean
velocity $v$ and the dispersion constant $D$ for any driving force $f$ above a
putative depi... | 2208.05031v2 |
2022-09-19 | Stationary states of an active Brownian particle in a harmonic trap | We study the stationary states of an over-damped active Brownian particle
(ABP) in a harmonic trap in two dimensions, via mathematical calculations and
numerical simulations. In addition to translational diffusion, the ABP
self-propels with a certain velocity, whose magnitude is constant, but its
direction is subject t... | 2209.09184v2 |
2022-09-25 | The Design of Observational Longitudinal Studies | This paper considers the design of observational longitudinal studies with a
continuous response and a binary time-invariant exposure, where, typically, the
exposure is unbalanced, the mean response in the two groups differs at baseline
and the measurement times might not be the same for all participants. We
consider g... | 2209.12129v1 |
2022-10-09 | How general is the strong cosmic censorship bound for quasinormal modes? | Hod's proposal claims that the least damped quasinormal mode of a black hole
must have the imaginary part smaller than half of the surface gravity at the
event horizon. The Strong Cosmic Censorship in General Relativity implies that
this bound must be even weaker: half of the surface gravity at the Cauchy
horizon. The ... | 2210.04314v2 |
2022-12-12 | Solving the Teukolsky equation with physics-informed neural networks | We use physics-informed neural networks (PINNs) to compute the first
quasi-normal modes of the Kerr geometry via the Teukolsky equation. This
technique allows us to extract the complex frequencies and separation constants
of the equation without the need for sophisticated numerical techniques, and
with an almost immedi... | 2212.06103v2 |
2023-01-27 | Thermal curvature perturbations in thermal inflation | We compute the power spectrum of super-horizon curvature perturbations
generated during a late period of thermal inflation, taking into account
fluctuation-dissipation effects resulting from the scalar flaton field's
interactions with the ambient radiation bath. We find that, at the onset of
thermal inflation, the flat... | 2301.11666v1 |
2023-02-20 | Adiabatic computing for optimal thermodynamic efficiency of information processing | Landauer's principle makes a strong connection between information theory and
thermodynamics by stating that erasing a one-bit memory at temperature $T_0$
requires an average energy larger than $W_{LB}=k_BT_0 \ln2$, with $k_B$
Boltzmann's constant. This tiny limit has been saturated in model experiments
using quasi-sta... | 2302.09957v2 |
2023-03-12 | Can gravitational vacuum condensate stars be a dark energy source? | Gravitational vacuum condensate stars, also known as gravastars, have been
proposed as an alternative to black holes. Their interior contains a perfect
fluid with an equation of state akin to that of a cosmological constant. For
this reason, they have recently been considered as a possible astrophysical
source of dark ... | 2303.06630v1 |
2023-03-23 | A Computational Study of Cluster Dynamics in Structural Lubricity: Role of Cluster Rotation | We present a computational study of sliding between gold clusters and a
highly oriented pyrolytic graphite substrate, a material system that exhibits
ultra-low friction due to structural lubricity. By means of molecular dynamics,
it is found that clusters may undergo spontaneous rotations during manipulation
as a resul... | 2303.13707v1 |
2023-04-12 | Using Demand Response to Improve Power System Small-Signal Stability | With the increase of uncertain and intermittent renewable energy supply on
the grid, the power system has become more vulnerable to instability. In this
paper, we develop a demand response strategy to improve power system
small-signal stability. We pose the problem as an optimization problem wherein
the total demand-re... | 2304.05573v2 |
2023-04-19 | Memory-induced oscillations of a driven particle in a dissipative correlated medium | The overdamped dynamics of a particle is in general affected by its
interaction with the surrounding medium, especially out of equilibrium, and
when the latter develops spatial and temporal correlations. Here we consider
the case in which the medium is modeled by a scalar Gaussian field with
relaxational dynamics, and ... | 2304.09684v2 |
2023-05-03 | Solving irreducible stochastic mean-payoff games and entropy games by relative Krasnoselskii-Mann iteration | We analyse an algorithm solving stochastic mean-payoff games, combining the
ideas of relative value iteration and of Krasnoselskii-Mann damping. We derive
parameterized complexity bounds for several classes of games satisfying
irreducibility conditions. We show in particular that an
$\epsilon$-approximation of the valu... | 2305.02458v1 |
2023-05-14 | Adiabatic manipulation of a system interacting with a spin-bath | Stimulated Raman Adiabatic Passage, a very efficient technique for
manipulating a quantum system based on the adiabatic theorem, is analyzed in
the case where the manipulated physical system is interacting with a spin bath.
Exploitation of the rotating wave approximation allows for the identification
of a constant of m... | 2305.08209v3 |
2023-06-08 | Energy Efficient Skyrmion based Oscillator on Thermocoupled Nanotrack | The magnetic skyrmion-based spin transfer nano-oscillators (STNO) are the
potential candidates for next-generation microwave signal generator and has
gained popularity due to their performance, integrability and compatibility
with existing CMOS technology. However, these devices suffer from the Joule
heating problem th... | 2306.05164v1 |
2023-08-31 | Apply Non-Hermitian Physics to Realize Ultra-High-Quality Factors of Optically Trapped Particles | Optical trapping and binding systems are non-Hermitian. On one hand, the
optical force is non-Hermitian and may pump energy into the trapped particle
when the non-Hermiticity is sufficiently large. On the other hand, the ambient
damping constitutes a loss to the particle. Here, we show that in a
low-friction environmen... | 2308.16502v1 |
2023-09-06 | BV solutions to a hyperbolic system of balance laws with logistic growth | We study BV solutions for a $2\times2$ system of hyperbolic balance laws. We
show that when initial data have small total variation on $(-\infty,\infty)$
and small amplitude, and decay sufficiently fast to a constant equilibrium
state as $|x|\rightarrow\infty$, a Cauchy problem (with generic data) has a
unique admissib... | 2309.03129v1 |
2023-10-09 | Anomaly and Brownian fluid particle in Navier-Stokes turbulence | We investigate the Navier-Stokes turbulence driven by a stochastic random
Gaussian force. Using a field-theoretic approach, we uncover an anomaly that
brings hidden structure to the theory. The anomaly is generated by a
non-self-adjoint operator of the Jacobian and it follows the symmetries of the
stochastic Navier-Sto... | 2310.06007v3 |
2023-11-02 | A Novel Adaptive Inertia Strategy in Large-Scale Electric Power Grids | The increasing penetration of new renewable sources of energy in today's
power grids is accompanied by a decrease in available electromechanical
inertia. This leads to a reduced dynamical stability. To counterbalance this
effect, virtual synchronous generators have been proposed to emulate
conventional generators and p... | 2311.01350v1 |
2023-11-19 | Two-step BEC coming from a temperature dependent energy gap | We report the effects on the thermodynamic properties of a 3D Bose gas caused
by a temperature dependent energy gap $\Delta (T)$ at the lower edge of the
energy spectrum of the particles constituting the Bose gas which behaves like
an ideal Bose gas when the gap is removed. Explicit formulae are given for the
critical ... | 2311.11447v1 |
2024-02-08 | Numerical solution of the Newtonian plane Couette flow with linear dynamic wall slip | An efficient numerical approach based on weighted average finite differences
is used to solve the Newtonian plane Couette flow with wall slip, obeying a
dynamic slip law that generalizes the Navier slip law with the inclusion of a
relaxation term. Slip is exhibited only along the fixed plate, and the motion
is triggere... | 2402.05736v1 |
2024-02-09 | Local exact controllability to the trajectories of the convective Brinkman-Forchheimer equations | In this article, we discuss the local exact controllability to trajectories
of the following convective Brinkman-Forchheimer (CBF) equations (or damped
Navier-Stokes equations) defined in a bounded domain $\Omega
\subset\mathbb{R}^d$ ($d=2,3$) with smooth boundary:
\begin{align*}
\frac{\partial\boldsymbol{u}}{\pa... | 2402.06335v1 |
2024-03-15 | Beam Dynamics Framework Incorporating Acceleration to Define the Minimum Aperture in Two Focusing Schemes for Proton Radiotherapy Linac | In this paper, a self-consistent transverse beam dynamics framework is
demonstrated, that incorporates acceleration into the transverse beam dynamics
studies for a proton linac machine. Two focusing schemes are developed and
discussed; the FODO-like scheme, and the minimum aperture scheme. The FODO-like
scheme is a sim... | 2403.10212v1 |
2024-03-19 | Unraveling the dynamics of magnetization in topological insulator-ferromagnet heterostructures via spin-orbit torque | Spin-orbit coupling stands as a pivotal determinant in the realm of condensed
matter physics. In recent, its profound influence on spin dynamics opens up a
captivating arena with promising applications. Notably, the topological
insulator-ferromagnet heterostructure has been recognized for inducing spin
dynamics through... | 2403.12701v1 |
2024-03-25 | Detection of spin pumping free of rectification and thermal artefacts in molecular-based ferromagnetic insulator V[TCNE]x~2 | The molecular-based ferrimagnetic insulator V(TCNE)x has gained recent
interest for efficient spin-wave excitation due to its low Gilbert damping
ratio a=4E-5, and narrow ferromagnetic resonance linewidth f=1Oe. Here we
report a clean spin pumping signal detected on V(TCNE)x/metal bilayer
structures, free from spin rec... | 2403.16429v2 |
2024-03-28 | Quantum asymptotic amplitude for quantum oscillatory systems from the Koopman operator viewpoint | We have recently proposed a fully quantum-mechanical definition of the
asymptotic phase for quantum nonlinear oscillators, which is also applicable in
the strong quantum regime [Kato and Nakao 2022 Chaos 32 063133]. In this study,
we propose a definition of the quantum asymptotic amplitude for quantum
oscillatory syste... | 2403.19297v1 |
2024-04-05 | Stability Analysis of Adaptive Model Predictive Control Using the Circle and Tsypkin Criteria | Absolute stability is a technique for analyzing the stability of Lur'e
systems, which arise in diverse applications, such as oscillators with
nonlinear damping or nonlinear stiffness. A special class of Lur'e systems
consists of self-excited systems (SES), in which bounded oscillations arise
from constant inputs. In ma... | 2404.04170v1 |
1999-08-16 | Thermal Equilibrium Curves and Turbulent Mixing in Keplerian Accretion Disks | We consider vertical heat transport in Keplerian accretion disks, including
the effects of radiation, convection, and turbulent mixing driven by the
Balbus-Hawley instability, in astronomical systems ranging from dwarf novae
(DNe), and soft X-ray transients (SXTs), to active galactic nuclei (AGN). We
propose a modified... | 9908166v1 |
2005-01-10 | On variations in the fine-structure constant and stellar pollution of quasar absorption systems | At redshifts z_abs < 2, quasar absorption-line constraints on space-time
variations in the fine-structure constant, alpha, rely on the comparison of
MgII and FeII transition wavelengths. One potentially important uncertainty is
the relative abundance of Mg isotopes in the absorbers which, if different from
solar, can c... | 0501168v2 |
1994-04-11 | Nonlinear Viscous Vortex Motion in Two-Dimensional Josephson-Junction Arrays | When a vortex in a two-dimensional Josephson junction array is driven by a
constant external current it may move as a particle in a viscous medium. Here
we study the nature of this viscous motion. We model the junctions in a square
array as resistively and capacitively shunted Josephson junctions and carry out
numerica... | 9404022v1 |
2002-09-20 | Onset of Convection in a Very Compressible Fluid : The Transient Toward Steady State | We analyze the time profile $\Delta T(t)$ of the temperature difference,
measured across a very compressible supercritical $^3$He fluid layer in its
convective state. The experiments were done along the critical isochore in a
Rayleigh-B\'{e}nard cell after starting the vertical constant heat flow $q$.
For $q$ sufficien... | 0209495v1 |
2004-10-14 | Cold Strongly Coupled Atoms Make a Near-perfect Liquid | Feshbach resonances of trapped ultracold alkali atoms allow to vary the
atomic scattering length a. At very large values of a the system enters an
universal strongly coupled regime in which its properties--the ground state
energy, pressure {\it etc.}--become independent of a. We discuss transport
properties of such sys... | 0410067v2 |
2004-09-24 | Oscillator model for dissipative QED in an inhomogeneous dielectric | The Ullersma model for the damped harmonic oscillator is coupled to the
quantised electromagnetic field. All material parameters and interaction
strengths are allowed to depend on position. The ensuing Hamiltonian is
expressed in terms of canonical fields, and diagonalised by performing a
normal-mode expansion. The com... | 0409161v1 |
2007-07-30 | Extended Quintessence with non-minimally coupled phantom scalar field | We investigate evolutional paths of an extended quintessence with a
non-minimally coupled phantom scalar field $\psi$ to the Ricci curvature. The
dynamical system methods are used to investigate typical regimes of dynamics at
the late time. We demonstrate that there are two generic types of evolutional
scenarios which ... | 0707.4471v2 |
2009-07-14 | Nonlinear Schrödinger Equation with Spatio-Temporal Perturbations | We investigate the dynamics of solitons of the cubic Nonlinear Schr\"odinger
Equation (NLSE) with the following perturbations: non-parametric
spatio-temporal driving of the form $f(x,t) = a \exp[i K(t) x]$, damping, and a
linear term which serves to stabilize the driven soliton. Using the time
evolution of norm, moment... | 0907.2438v2 |
2012-09-11 | Macroscopic quantum tunneling of two coupled particles in the presence of a transverse magnetic field | Two coupled particles of identical masses but opposite charges, with a
constant transverse external magnetic field and an external potential,
interacting with a bath of harmonic oscillators are studied. We show that the
problem cannot be mapped to a one-dimensional problem like the one in Ref.
\cite{pa}, it strictly re... | 1209.2307v4 |
2013-08-28 | On the evolution of the momentarily static radiation free data in the Apostolatos - Thorne cylindrical shell model | We study the evolution of the "Momentarily Static and Radiation Free" (MSRF)
initial data for the Apostolatos - Thorne cylindrical shell model. We analyze
the relation between the parameters characterizing the MSRF data those for the
corresponding final static configuration, and show that there is a priori no
conflict ... | 1308.6296v1 |
2014-01-17 | Co2FeAl Heusler thin films grown on Si and MgO substrates: annealing temperature effect | 10 nm and 50 nm Co$_{2}$FeAl (CFA) thin films have been deposited on MgO(001)
and Si(001) substrates by magnetron sputtering and annealed at different
temperatures. X-rays diffraction revealed polycrystalline or epitaxial growth
(according to the relation CFA(001)[110]//MgO(001)[100] epitaxial relation),
respectively f... | 1401.4397v1 |
2014-02-04 | Complete Tidal Evolution of Pluto-Charon | Both Pluto and its satellite Charon have rotation rates synchronous with
their orbital mean motion. This is the theoretical end point of tidal evolution
where transfer of angular momentum has ceased. Here we follow Pluto's tidal
evolution from an initial state having the current total angular momentum of
the system but... | 1402.0625v1 |
2014-05-22 | Tagged particle diffusion in one-dimensional systems with Hamiltonian dynamics - II | We study various temporal correlation functions of a tagged particle in
one-dimensional systems of interacting point particles evolving with
Hamiltonian dynamics. Initial conditions of the particles are chosen from the
canonical thermal distribution. The correlation functions are studied in finite
systems, and their fo... | 1405.5718v2 |
2014-09-01 | Nitric Oxide as stress inducer and synchronizer of p53 dynamics | We study how the temporal behaviours of p53 and MDM2 are affected by stress
inducing bioactive molecules NO (Nitric Oxide) in the p53-MDM2-NO regulatory
network. We also study synchronization among a group of identical stress
systems arranged in a three dimensional array with nearest neighbour diffusive
coupling. The r... | 1409.0528v1 |
2015-10-15 | Markov Chain Analysis of Cumulative Step-size Adaptation on a Linear Constrained Problem | This paper analyzes a (1, $\lambda$)-Evolution Strategy, a randomized
comparison-based adaptive search algorithm, optimizing a linear function with a
linear constraint. The algorithm uses resampling to handle the constraint. Two
cases are investigated: first the case where the step-size is constant, and
second the case... | 1510.04409v1 |
2016-02-02 | Planck constraints on scalar-tensor cosmology and the variation of the gravitational constant | Cosmological constraints on the scalar-tensor theory of gravity by analyzing
the angular power spectrum data of the cosmic microwave background (CMB)
obtained from the Planck 2015 results are presented. We consider the harmonic
attractor model, in which the scalar field has a harmonic potential with
curvature ($\beta$)... | 1602.00809v2 |
2016-05-06 | Eisenhart lifts and symmetries of time-dependent systems | Certain dissipative systems, such as Caldirola and Kannai's damped simple
harmonic oscillator, may be modelled by time-dependent Lagrangian and hence
time dependent Hamiltonian systems with $n$ degrees of freedom. In this paper
we treat these systems, their projective and conformal symmetries as well as
their quantisat... | 1605.01932v2 |
2016-05-24 | Coherent magneto-elastic oscillations in superfluid magnetars | We study the effect of superfluidity on torsional oscillations of highly
magnetised neutron stars (magnetars) with a microphysical equation of state by
means of two-dimensional, magnetohydrodynamical- elastic simulations. The
superfluid properties of the neutrons in the neutron star core are treated in a
parametric way... | 1605.07638v1 |
2016-06-28 | Negative stiffness and modulated states in active nematics | We examine the dynamics of a compressible active nematic liquid crystal on a
frictional substrate. When frictional damping dominates over viscous
dissipation, we eliminate flow in favor of active stresses to obtain a minimal
dynamical model for the nematic order parameter, with elastic constants
renormalized by activit... | 1606.08786v2 |
2017-03-11 | Magnonic crystals - prospective structures for shaping spin waves in nanoscale | We have investigated theoretically band structure of spin waves in magnonic
crystals with periodicity in one-(1D), two- (2D) and three-dimensions (3D). We
have solved Landau-Lifshitz equation with the use of plane wave method, finite
element method in frequency domain and micromagnetic simulations in time domain
to fin... | 1703.04012v1 |
2018-02-17 | Superconductivity induced by flexural modes in non $σ_{\rm h}$-symmetric Dirac-like two-dimensional materials: A theoretical study for silicene and germanene | In two-dimensional crystals that lack symmetry under reflections on the
horizontal plane of the lattice (non-$\sigma_{\rm h}$-symmetric), electrons can
couple to flexural modes (ZA phonons) at first order. We show that in materials
of this type that also exhibit a Dirac-like electron dispersion, the strong
coupling can... | 1802.06272v1 |
2019-04-29 | A nonlinear subgrid-scale model for large-eddy simulations of rotating turbulent flows | Rotating turbulent flows form a challenging test case for large-eddy
simulation (LES). We, therefore, propose and validate a new subgrid-scale (SGS)
model for such flows. The proposed SGS model consists of a dissipative eddy
viscosity term as well as a nondissipative term that is nonlinear in the
rate-of-strain and rat... | 1904.12748v1 |
2020-04-03 | Probing modified gravity theories and cosmology using gravitational-waves and associated electromagnetic counterparts | The direct detection of gravitational waves by the LIGO-Virgo collaboration
has opened a new window with which to measure cosmological parameters such as
the Hubble constant $H_0$, and also probe general relativity on large scales.
In this paper we present a new phenomenological approach, together with its
inferencial ... | 2004.01632v2 |
2021-08-18 | Velocity auto correlation function of a confined Brownian particle | Motivated by the simple models of molecular motor obeying a linear
force-velocity relation, we have studied the stochastic dynamics of a Brownian
particle in the presence of a linear velocity dependent force,
$f_s(1-\frac{v}{v_0})$ where $f_{s}$ is a constant. The position and velocity
auto correlation functions in dif... | 2108.07922v1 |
2021-12-21 | Fast long-wavelength exchange spin waves in partially-compensated Ga:YIG | Spin waves in yttrium iron garnet (YIG) nano-structures attract increasing
attention from the perspective of novel magnon-based data processing
applications. For short wavelengths needed in small-scale devices, the group
velocity is directly proportional to the spin-wave exchange stiffness constant
$\lambda_\mathrm{ex}... | 2112.11348v1 |
2022-04-11 | Forecast and backcast of the solar cycles | Solar cycle is modeled as a forced and damped harmonic oscillator and the
amplitudes, frequencies, phases and decay factors of such a harmonic oscillator
are estimated by non-linear fitting the equation of sinusoidal and transient
parts to the sunspot and irradiance (proxy for the sunspot) data for the years
1700-2008.... | 2204.04818v1 |
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