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2020-09-17 | Temperature Dependent Non-linear Damping in Palladium Nano-mechanical Resonators | Advances in nano-fabrication techniques has made it feasible to observe
damping phenomena beyond the linear regime in nano-mechanical systems. In this
work, we report cubic non-linear damping in palladium nano-mechanical
resonators. Nano-scale palladium beams exposed to a $H_2$ atmosphere become
softer and display enha... | 2009.08324v1 |
2020-09-22 | Sharp exponential decay rates for anisotropically damped waves | In this article, we study energy decay of the damped wave equation on compact
Riemannian manifolds where the damping coefficient is anisotropic and modeled
by a pseudodifferential operator of order zero. We prove that the energy of
solutions decays at an exponential rate if and only if the damping coefficient
satisfies... | 2009.10832v2 |
2020-12-25 | Information constraint in open quantum systems | We propose an effect called information constraint which is characterized by
the existence of different decay rates of signal strengths propagating along
opposite directions. It is an intrinsic property of a type of open quantum
system, which does not rely on boundary conditions. We define the value of
information cons... | 2012.13583v3 |
2021-04-29 | Non-linear damping of standing kink waves computed with Elsasser variables | In a previous paper, we computed the energy density and the non-linear energy
cascade rate for transverse kink waves using Elsasser variables. In this paper,
we focus on the standing kink waves, which are impulsively excited in coronal
loops by external perturbations. We present an analytical calculation to
compute the... | 2104.14331v1 |
2021-05-31 | Revisiting the Plasmon Radiation Damping of Gold Nanorods | Noble metal nanoparticles have been utilized for a vast amount of optical
applications. For the applications that used metal nanoparticles as nanosensors
and optical labeling, larger radiation damping is preferred (higher optical
signal). To get a deeper knowledge about the radiation damping of noble metal
nanoparticle... | 2105.14873v1 |
2021-06-23 | Bayesian evidence for a nonlinear damping model for coronal loop oscillations | Recent observational and theoretical studies indicate that the damping of
solar coronal loop oscillations depends on the oscillation amplitude. We
consider two mechanisms, linear resonant absorption and a nonlinear damping
model. We confront theoretical predictions from these models with observed data
in the plane of o... | 2106.12243v1 |
2021-07-13 | Convergence of iterates for first-order optimization algorithms with inertia and Hessian driven damping | In a Hilbert space setting, for convex optimization, we show the convergence
of the iterates to optimal solutions for a class of accelerated first-order
algorithms. They can be interpreted as discrete temporal versions of an
inertial dynamic involving both viscous damping and Hessian-driven damping. The
asymptotically ... | 2107.05943v1 |
2021-12-13 | Effect of interfacial damping on high-frequency surface wave resonance on a nanostrip-bonded substrate | Since surface acoustic waves (SAW) are often generated on substrates to which
nanostrips are periodically attached, it is very important to consider the
effect of interface between the deposited strip and the substrate surface,
which is an unavoidable issue in manufacturing. In this paper, we propose a
theoretical mode... | 2112.06367v1 |
2021-12-13 | Cosmic ray streaming in the turbulent interstellar medium | We study the streaming instability of GeV$-100~$GeV cosmic rays (CRs) and its
damping in the turbulent interstellar medium (ISM). We find that the damping of
streaming instability is dominated by ion-neutral collisional damping in weakly
ionized molecular clouds, turbulent damping in the highly ionized warm medium,
and... | 2112.06941v2 |
2022-05-27 | Scalar field damping at high temperatures | The motion of a scalar field that interacts with a hot plasma, like the
inflaton during reheating, is damped, which is a dissipative process. At high
temperatures the damping can be described by a local term in the effective
equation of motion. The damping coefficient is sensitive to multiple
scattering. In the loop ex... | 2205.14166v2 |
2022-09-13 | Latest results from the DAMPE space mission | The DArk Matter Particle Explorer (DAMPE) is a space-based particle detector
launched on December 17th, 2015 from the Jiuquan Satellite Launch Center
(China). The main goals of the DAMPE mission are the study of galactic cosmic
rays (CR), the electron-positron energy spectrum, gamma-ray astronomy, and
indirect dark mat... | 2209.06014v1 |
2022-10-25 | Microscopic structure of electromagnetic whistler wave damping by kinetic mechanisms in hot magnetized Vlasov plasmas | The kinetic damping mechanism of low frequency transverse perturbations
propagating parallel to the magnetic field in a magnetized warm electron plasma
is simulated by means of electromagnetic (EM) Vlasov simulations. The
short-time-scale damping of the electron magnetohydrodynamic whistler
perturbations and underlying... | 2210.13764v1 |
2022-12-02 | Equivalence between the energy decay of fractional damped Klein-Gordon equations and geometric conditions for damping coefficients | We consider damped $s$-fractional Klein--Gordon equations on $\mathbb{R}^d$,
where $s$ denotes the order of the fractional Laplacian. In the one-dimensional
case $d = 1$, Green (2020) established that the exponential decay for $s \geq
2$ and the polynomial decay of order $s/(4-2s)$ hold if and only if the damping
coeff... | 2212.01029v4 |
2023-01-13 | An artificially-damped Fourier method for dispersive evolution equations | Computing solutions to partial differential equations using the fast Fourier
transform can lead to unwanted oscillatory behavior. Due to the periodic nature
of the discrete Fourier transform, waves that leave the computational domain on
one side reappear on the other and for dispersive equations these are typically
hig... | 2301.05789v1 |
2023-03-07 | Stabilization of the wave equation on larger-dimension tori with rough dampings | This paper deals with uniform stabilization of the damped wave equation. When
the manifold is compact and the damping is continuous, the geometric control
condition is known to be necessary and sufficient. In the case where the
damping is a sum of characteristic functions of polygons on a two-dimensional
torus, a resul... | 2303.03733v4 |
2023-07-10 | The Characteristic Shape of Damping Wings During Reionization | Spectroscopic analysis of Ly$\alpha$ damping wings of bright sources at $z>6$
is a promising way to measure the reionization history of the universe.
However, the theoretical interpretation of the damping wings is challenging due
to the inhomogeneous nature of the reionization process and the proximity
effect of bright... | 2307.04797v1 |
2023-07-17 | Dissipation in solids under oscillatory shear: Role of damping scheme and sample thickness | We study dissipation as a function of sample thickness in solids under global
oscillatory shear applied to the top layer of the sample. Two types of damping
mechanism are considered: Langevin and Dissipative Particle Dynamics (DPD). In
the regime of low driving frequency, and under strain-controlled conditions, we
obse... | 2307.08413v1 |
2023-08-17 | A low-rank algorithm for strongly damped wave equations with visco-elastic damping and mass terms | Damped wave equations have been used in many real-world fields. In this
paper, we study a low-rank solution of the strongly damped wave equation with
the damping term, visco-elastic damping term and mass term. Firstly, a
second-order finite difference method is employed for spatial discretization.
Then, we receive a se... | 2308.08888v2 |
2023-10-30 | Optimal backward uniqueness and polynomial stability of second order equations with unbounded damping | For general second order evolution equations, we prove an optimal condition
on the degree of unboundedness of the damping, that rules out finite-time
extinction. We show that control estimates give energy decay rates that
explicitly depend on the degree of unboundedness, and establish a dilation
method to turn existing... | 2310.19911v1 |
2024-03-12 | Modulational instability of nonuniformly damped, broad-banded waves: applications to waves in sea-ice | This paper sets out to explore the modulational (or Benjamin-Feir)
instability of a monochromatic wave propagating in the presence of damping such
as that induced by sea-ice on the ocean surface. The fundamental wave motion is
modelled using the spatial Zakharov equation, to which either uniform or
non-uniform (frequen... | 2403.07425v1 |
1994-05-12 | Black Hole Relics and Inflation: Limits on Blue Perturbation Spectra | Blue primordial power spectra have spectral index $n>1$ and arise naturally
in the recently proposed hybrid inflationary scenario. An observational upper
limit on {\em n} is derived by normalizing the spectrum at the quadrupole scale
and considering the possible overproduction of Planck mass relics formed in the
final ... | 9405027v1 |
1995-02-01 | Spectra and Statistics of Cosmic String Perturbations on the Microwave Background: A Monte Carlo Approach | Using Monte Carlo simulations of perturbations induced by cosmic strings on
the microwave background, we demonstrate the scale invariance of string
fluctuation patterns. By comparing string-induced fluctuation patterns with
gaussian random phase ones, we show that the non-gaussian signatures of the
string patterns are ... | 9502004v2 |
1999-04-16 | The Sunyaev-Zeldovich Effect as Microwave Foreground and Probe of Cosmology | The Sunyaev-Zel'dovich (SZ) effect from clusters of galaxies should yield a
significant signal in cosmic microwave background(CMB) experiments at small
angular scales ($\ell \ga 1000$). Experiments with sufficient frequency
coverage should be able to remove much of this signal in order to recover the
primary anisotropy... | 9904220v1 |
2000-12-05 | Near-IR Spectroscopy and Population Synthesis of Super Star Clusters in NGC 1569 | We present H- and K-band NIRSPEC spectroscopy of super star clusters (SSCs)
in the irregular starburst galaxy NGC 1569, obtained at the Keck Observatory.
We fit these photospheric spectra to NextGen model atmospheres to obtain
effective spectral types of clusters, and find that the information in both H-
and K-band spe... | 0012089v1 |
2001-05-14 | Understanding Cluster Gas Evolution and Fine-Scale CMB Anisotropy with Deep Sunyaev-Zel'dovich Effect Surveys | We investigate the impact of gas evolution on the expected yields from deep
Sunyaev-Zel'dovich (SZ) effect surveys as well as on the expected SZ effect
contribution to fine scale anisotropy in the Cosmic Microwave Background. The
approximate yields from SZ effect surveys are remarkably insensitive to gas
evolution, eve... | 0105229v1 |
2001-05-22 | Constraints on Omega_m, Omega_L, and Sigma_8, from Galaxy Cluster Redshift Distributions | We show that the counts of galaxy clusters in future deep cluster surveys can
place strong constraints on the matter density, Omega_m, the vacuum energy
density, Omega_L, and the normalization of the matter power spectrum, sigma_8.
Degeneracies between these parameters are different from those in studies of
either high... | 0105396v2 |
2002-05-27 | Radio Point Sources and the Thermal SZ Power Spectrum | Radio point sources are strongly correlated with clusters of galaxies, so a
significant fraction of the thermal Sunyaev-Zel'dovich (SZ) effect signal could
be affected by point source contamination. Based on empirical estimates of the
radio galaxy population, it is shown that the rms temperature fluctuations of
the the... | 0205467v2 |
2002-07-29 | Measuring Cluster Peculiar Velocities and Temperatures at cm and mm Wavelengths | We present a detailed investigation of issues related to the measurement of
peculiar velocities and temperatures using Sunyaev-Zel'dovich (SZ) effects. We
estimate the accuracy to which peculiar velocities and gas temperatures of
distant galaxy clusters could be measured. With uK sensitivity on arcminute
scales at seve... | 0207600v2 |
2002-07-29 | CMB-Normalized Predictions for Sunyaev-Zel'dovich effect fluctuations | We predict the level of small-scale anisotropy in the cosmic microwave
background (CMB) due to the Sunyaev--Zel'dovich (SZ) effect for the ensemble of
cosmological models that are consistent with current measurements of
large-scale CMB anisotropy. We argue that the recently reported detections of
the small-scale (arcmi... | 0207633v1 |
2002-08-08 | Cosmology with the Sunyaev-Zel'dovich Effect | The Sunyaev-Zel'dovich effect (SZE) provides a unique way to map the
large-scale structure of the universe as traced by massive clusters of
galaxies. As a spectral distortion of the cosmic microwave background, the SZE
is insensitive to the redshift of the galaxy cluster, making it well-suited for
studies of clusters a... | 0208192v1 |
2002-09-25 | External Shear in Quadruply Imaged Lens Systems | We use publicly available N-body simulations and semi-analytic models of
galaxy formation to estimate the levels of external shear due to structure near
the lens in gravitational lens systems. We also describe two selection effects,
specific to four-image systems, that enhance the probability of observing
systems to ha... | 0209532v2 |
2003-05-21 | A Method for Mapping the Temperature Profile of X-ray Clusters Through Radio Observations | Many of the most luminous extragalactic radio sources are located at the
centers of X-ray clusters, and so their radiation must be scattered by the
surrounding hot gas. We show that radio observations of the highly-polarized
scattered radiation (which depends on the electron density distribution) in
combination with th... | 0305417v1 |
2006-09-26 | Reconstructing the Thomson Optical Depth due to Patchy Reionization with 21-cm Fluctuation Maps | Large fluctuations in the electron column density can occur during the
reionization process. We investigate the possibility of deriving the electron
density fluctuations through detailed mapping of the redshifted 21-cm emission
from the neutral medium during reionization. We find that the
electron-scattering optical de... | 0609689v2 |
1998-07-06 | Field Driven Thermostated System : A Non-Linear Multi-Baker Map | In this paper, we discuss a simple model for a field driven, thermostated
random walk that is constructed by a suitable generalization of a multi-baker
map. The map is a usual multi-baker, but perturbed by a thermostated external
field that has many of the properties of the fields used in systems with
Gaussian thermost... | 9807011v2 |
2006-01-19 | Fluctuation theorem for constrained equilibrium systems | We discuss the fluctuation properties of equilibrium chaotic systems with
constraints such as iso-kinetic and Nos\'e-Hoover thermostats. Although the
dynamics of these systems does not typically preserve phase-space volumes, the
average phase-space contraction rate vanishes, so that the stationary states
are smooth. Ne... | 0601435v1 |
2003-06-12 | ATLAS Data Challenge 1 | In 2002 the ATLAS experiment started a series of Data Challenges (DC) of
which the goals are the validation of the Computing Model, of the complete
software suite, of the data model, and to ensure the correctness of the
technical choices to be made. A major feature of the first Data Challenge (DC1)
was the preparation ... | 0306052v1 |
2004-06-21 | Long Nonbinary Codes Exceeding the Gilbert - Varshamov Bound for any Fixed Distance | Let A(q,n,d) denote the maximum size of a q-ary code of length n and distance
d. We study the minimum asymptotic redundancy \rho(q,n,d)=n-log_q A(q,n,d) as n
grows while q and d are fixed. For any d and q<=d-1, long algebraic codes are
designed that improve on the BCH codes and have the lowest asymptotic
redundancy \rh... | 0406039v3 |
2006-08-19 | Algorithmic linear dimension reduction in the l_1 norm for sparse vectors | This paper develops a new method for recovering m-sparse signals that is
simultaneously uniform and quick. We present a reconstruction algorithm whose
run time, O(m log^2(m) log^2(d)), is sublinear in the length d of the signal.
The reconstruction error is within a logarithmic factor (in m) of the optimal
m-term approx... | 0608079v1 |
2007-03-06 | LIBOPT - An environment for testing solvers on heterogeneous collections of problems - Version 1.0 | The Libopt environment is both a methodology and a set of tools that can be
used for testing, comparing, and profiling solvers on problems belonging to
various collections. These collections can be heterogeneous in the sense that
their problems can have common features that differ from one collection to the
other. Libo... | 0703025v1 |
1995-09-19 | Harmonic Maps with Prescribed Singularities on Unbounded Domains | The Einstein/Abelian-Yang-Mills Equations reduce in the stationary and
axially symmetric case to a harmonic map with prescribed singularities
$\p\colon\R^3\sm\Sigma\to\H^{k+1}_\C$ into the $(k+1)$-dimensional complex
hyperbolic space. In this paper, we prove the existence and uniqueness of
harmonic maps with prescribed... | 9509003v1 |
1994-12-12 | N-Black Hole Stationary and Axially Symmetric Solutions of the Einstein-Maxwell Equations | The Einstein/Maxwell equations reduce in the stationary and axially symmetric
case to a harmonic map with prescribed singularities phi: R^3\Sigma -> H^2_C,
where Sigma is a subset of the axis of symmetry, and H^2_C is the complex
hyperbolic plane. Motivated by this problem, we prove the existence and
uniqueness of harm... | 9412036v2 |
1997-11-17 | Novel Electroweak Symmetry Breaking Conditions From Quantum Effects In The MSSM | We present, in the context of the Minimal Supersymmetric Standard Model, a
detailed one-loop analytic study of the minimization conditions of the
effective potential in the Higgs sector.
Special emphasis is put on the role played by $Str M^4$ in the determination
of the electroweak symmetry breaking conditions, where... | 9711356v1 |
1999-01-08 | On the fourth adjoint Contractions of divisorial and fiber types | In this paper, we will list up all the cases for the ray contractions of
divisorial and fiber types for smooth projective varieties of dimension five.
These are obtained as a corollary from the lists of n-dimensional k-th adjoint
contractions f: X -> Y of the same types for k=1,2,3 and 4 (n> or =5). The
lists for k=1,2... | 9901033v2 |
2004-04-19 | Asymptotic Improvement of the Gilbert-Varshamov Bound on the Size of Binary Codes | Given positive integers $n$ and $d$, let $A_2(n,d)$ denote the maximum size
of a binary code of length $n$ and minimum distance $d$. The well-known
Gilbert-Varshamov bound asserts that $A_2(n,d) \geq 2^n/V(n,d-1)$, where
$V(n,d) = \sum_{i=0}^{d} {n \choose i}$ is the volume of a Hamming sphere of
radius $d$. We show th... | 0404325v1 |
2005-11-03 | On the automorphism group of generalized Baumslag-Solitar groups | A generalized Baumslag-Solitar group (GBS group) is a finitely generated
group $G$ which acts on a tree with all edge and vertex stabilizers infinite
cyclic. We show that Out(G) either contains non-abelian free groups or is
virtually nilpotent of class at most 2. It has torsion only at finitely many
primes.
One may d... | 0511083v1 |
2001-07-08 | Statistically Preserved Structures in Shell Models of Passive Scalar Advection | It was conjectured recently that Statiscally Preserved Structures underlie
the statistical physics of turbulent transport processes. We analyze here in
detail the time-dependent (non compact) linear operator that governs the
dynamics of correlation functions in the case of shell models of passive scalar
advection. The ... | 0107016v1 |
2001-11-13 | Statistically Preserved Structures and Anomalous Scaling in Turbulent Active Scalar Advection | The anomalous scaling of correlation functions in the turbulent statistics of
active scalars (like temperature in turbulent convection) is understood in
terms of an auxiliary passive scalar which is advected by the same turbulent
velocity field. While the odd-order correlation functions of the active and
passive fields... | 0111030v1 |
2003-03-27 | On the parametric dependences of a class of non-linear singular maps | We discuss a two-parameter family of maps that generalize piecewise linear,
expanding maps of the circle. One parameter measures the effect of a
non-linearity which bends the branches of the linear map. The second parameter
rotates points by a fixed angle. For small values of the nonlinearity
parameter, we compute the ... | 0303062v1 |
2001-06-06 | The Secrecy Capacity of Practical Quantum Cryptography | Quantum cryptography has attracted much recent attention due to its potential
for providing secret communications that cannot be decrypted by any amount of
computational effort. This is the first analysis of the secrecy of a practical
implementation of the BB84 protocol that simultaneously takes into account and
presen... | 0106033v1 |
2005-11-17 | Quantum Computer Condition: Stability, Classical Computation and Norms | The Quantum Computer Condition (QCC) provides a rigorous and completely
general framework for carrying out analyses of questions pertaining to
fault-tolerance in quantum computers. In this paper we apply the QCC to the
problem of fluctuations and systematic errors in the values of characteristic
parameters in realistic... | 0511177v1 |
2006-12-19 | On the use of photonic N00N states for practical quantum interferometry | The performance of photonic $N00N$ states, propagating in an attenuating
medium, is analyzed with respect to phase estimation. It is shown that, for
$N00N$ states propagating through a lossy medium, the Heisenberg limit is never
achieved. It is also shown that, for a given value of $N$, a signal comprised
of an attenua... | 0612156v1 |
2007-05-22 | Analysis of evidence of Mars life | Gillevinia straata, the scientific name [1, 2] recognizing the first
extraterrestrial living form ever nomenclated, as well as the existence of a
new biological kingdom, Jakobia, in a new biosphere -Marciana- of what now has
become the living system Solaria, is grounded on old evidence reinterpreted in
the light of new... | 0705.3176v3 |
2007-06-26 | Feedback in the Antennae Galaxies (NGC 4038/9): I. High-Resolution Infrared Spectroscopy of Winds from Super Star Clusters | We present high-resolution (R ~ 24,600) near-IR spectroscopy of the youngest
super star clusters (SSCs) in the prototypical starburst merger, the Antennae
Galaxies. These SSCs are young (3-7 Myr old) and massive (10^5 - 10^7 M_sun for
a Kroupa IMF) and their spectra are characterized by broad, extended Br-gamma
emissio... | 0706.3935v1 |
2007-06-29 | Reliable Final Computational Results from Faulty Quantum Computation | In this paper we extend both standard fault tolerance theory and Kitaev's
model for quantum computation, combining them so as to yield quantitative
results that reveal the interplay between the two. Our analysis establishes a
methodology that allows us to quantitatively determine design parameters for a
quantum compute... | 0707.0008v1 |
2007-08-24 | Quantum Sensor Miniaturization | The classical bound on image resolution defined by the Rayleigh limit can be
beaten by exploiting the properties of quantum mechanical entanglement. If
entangled photons are used as signal states, the best possible resolution is
instead given by the Heisenberg limit, an improvement proportional to the
number of entangl... | 0708.3403v1 |
2007-09-02 | A Universal Operator Theoretic Framework for Quantum Fault Tolerance | In this paper we introduce a universal operator theoretic framework for
quantum fault tolerance. This incorporates a top-down approach that implements
a system-level criterion based on specification of the full system dynamics,
applied at every level of error correction concatenation. This leads to more
accurate determ... | 0709.0128v3 |
2007-10-25 | Ordering in red abalone nacre | Red abalone nacre is an intensely studied biomineral, and yet its formation
mechanism remains poorly understood. Here we report quantitative measurements
probing the degree of order of the aragonite tablets in nacre, and show that
order develops over a distance of about 50 microns. These observations indicate
that the ... | 0710.4573v1 |
2007-11-01 | Interaction effects in mixed-valent Kondo insulators | We study theoretically the class of mixed-valent Kondo insulators, employing
a recently developed local moment approach to heavy Fermion systems using the
asymmetric periodic Anderson model (PAM). Novel features in spectra and
transport, observable experimentally but lying outside the scope of the
symmetric PAM or the ... | 0711.0121v1 |
2008-01-31 | Counting growth types of automorphisms of free groups | Given an automorphism of a free group $F_n$, we consider the following
invariants: $e$ is the number of exponential strata (an upper bound for the
number of different exponential growth rates of conjugacy classes); $d$ is the
maximal degree of polynomial growth of conjugacy classes; $R$ is the rank of
the fixed subgrou... | 0801.4844v2 |
2008-02-29 | Heat conduction and Fourier's law in a class of many particle dispersing billiards | We consider the motion of many confined billiard balls in interaction and
discuss their transport and chaotic properties. In spite of the absence of mass
transport, due to confinement, energy transport can take place through binary
collisions between neighbouring particles. We explore the conditions under
which relaxat... | 0802.4455v3 |
2008-04-29 | Combining geometry and combinatorics: A unified approach to sparse signal recovery | There are two main algorithmic approaches to sparse signal recovery:
geometric and combinatorial. The geometric approach starts with a geometric
constraint on the measurement matrix and then uses linear programming to decode
information about the signal from its measurements. The combinatorial approach
constructs the m... | 0804.4666v1 |
2008-08-08 | Heat conductivity from molecular chaos hypothesis in locally confined billiard systems | We study the transport properties of a large class of locally confined
Hamiltonian systems, in which neighboring particles interact through hard core
elastic collisions. When these collisions become rare and the systems large, we
derive a Boltzmann-like equation for the evolution of the probability
densities. We solve ... | 0808.1179v2 |
2008-09-23 | On the derivation of Fourier's law in stochastic energy exchange systems | We present a detailed derivation of Fourier's law in a class of stochastic
energy exchange systems that naturally characterize two-dimensional mechanical
systems of locally confined particles in interaction. The stochastic systems
consist of an array of energy variables which can be partially exchanged among
nearest ne... | 0809.3967v2 |
2008-10-19 | Coding Theorems for Repeat Multiple Accumulate Codes | In this paper the ensemble of codes formed by a serial concatenation of a
repetition code with multiple accumulators connected through random
interleavers is considered. Based on finite length weight enumerators for these
codes, asymptotic expressions for the minimum distance and an arbitrary number
of accumulators lar... | 0810.3422v1 |
2008-12-09 | Statistical properties of time-reversible triangular maps of the square | Time reversal symmetric triangular maps of the unit square are introduced
with the property that the time evolution of one of their two variables is
determined by a piecewise expanding map of the unit interval. We study their
statistical properties and establish the conditions under which their
equilibrium measures hav... | 0812.1648v1 |
2009-03-20 | Fractality of the non-equilibrium stationary states of open volume-preserving systems: I. Tagged particle diffusion | Deterministic diffusive systems such as the periodic Lorentz gas, multi-baker
map, as well as spatially periodic systems of interacting particles, have
non-equilibrium stationary states with fractal properties when put in contact
with particle reservoirs at their boundaries. We study the macroscopic limits
of these sys... | 0903.3476v1 |
2009-03-20 | Fractality of the non-equilibrium stationary states of open volume-preserving systems: II. Galton boards | Galton boards are models of deterministic diffusion in a uniform external
field, akin to driven periodic Lorentz gases, here considered in the absence of
dissipation mechanism. Assuming a cylindrical geometry with axis along the
direction of the external field, the two-dimensional board becomes a model for
one-dimensio... | 0903.3849v1 |
2009-07-23 | On Possible Variation in the Cosmological Baryon Fraction | The fraction of matter that is in the form of baryons or dark matter could
have spatial fluctuations in the form of baryon-dark matter isocurvature
fluctuations. We use big bang nucleosynthesis calculations compared with
observed light element abundances as well as galaxy cluster gas fractions to
constrain cosmological... | 0907.3919v2 |
2009-08-28 | Chaos in cylindrical stadium billiards via a generic nonlinear mechanism | We describe conditions under which higher-dimensional billiard models in
bounded, convex regions are fully chaotic, generalizing the Bunimovich stadium
to dimensions above two. An example is a three-dimensional stadium bounded by a
cylinder and several planes; the combination of these elements may give rise to
defocusi... | 0908.4243v2 |
2009-09-23 | The Gilbert Arborescence Problem | We investigate the problem of designing a minimum cost flow network
interconnecting n sources and a single sink, each with known locations in a
normed space and with associated flow demands. The network may contain any
finite number of additional unprescribed nodes from the space; these are known
as the Steiner points.... | 0909.4270v2 |
2010-08-12 | Magnetization dynamics in the inertial regime: nutation predicted at short time scales | The dynamical equation of the magnetization has been reconsidered with
enlarging the phase space of the ferromagnetic degrees of freedom to the
angular momentum. The generalized Landau-Lifshitz-Gilbert equation that
includes inertial terms, and the corresponding Fokker-Planck equation, are then
derived in the framework... | 1008.2177v1 |
2010-09-20 | Diffusive properties of persistent walks on cubic lattices with application to periodic Lorentz gases | We calculate the diffusion coefficients of persistent random walks on cubic
and hypercubic lattices, where the direction of a walker at a given step
depends on the memory of one or two previous steps. These results are then
applied to study a billiard model, namely a three-dimensional periodic Lorentz
gas. The geometry... | 1009.3922v1 |
2010-11-03 | Existence of vertical spin stiffness in Landau-Lifshitz-Gilbert equation in ferromagnetic semiconductors | We calculate the magnetization torque due to the spin polarization of the
itinerant electrons by deriving the kinetic spin Bloch equations based on the
$s$-$d$ model. We find that the first-order gradient of the magnetization
inhomogeneity gives rise to the current-induced torques, which are consistent
to the previous ... | 1011.0871v1 |
2011-01-05 | The Fascinating World of Landau-Lifshitz-Gilbert Equation: An Overview | The Landau-Lifshitz-Gilbert (LLG) equation is a fascinating nonlinear
evolution equation both from mathematical and physical points of view. It is
related to the dynamics of several important physical systems such as
ferromagnets, vortex filaments, moving space curves, etc. and has intimate
connections with many of the... | 1101.1005v1 |
2011-02-05 | Graph Theory | This is a replacement paper. There are 6 chapters. The first two chapters are
introductory. The third chapter is on extremal graph theory. The fourth chapter
is about algebra in graph theory. The fifth chapter is focused on algorithms.
The third section of the fifth chapter deals with computable time. The sixth
chapter... | 1102.1087v11 |
2011-04-28 | The High-Redshift Neutral Hydrogen Signature of an Anisotropic Matter Power Spectrum | An anisotropic power spectrum will have a clear signature in the 21cm
radiation from high-redshift hydrogen. We calculate the expected power spectrum
of the intensity fluctuations in neutral hydrogen from before the epoch of
reionization, and predict the accuracy to which future experiments could
constrain a quadrupole... | 1104.5403v3 |
2011-06-30 | A generalisation of the Gilbert-Varshamov bound and its asymptotic evaluation | The Gilbert-Varshamov (GV) lower bound on the maximum cardinality of a q-ary
code of length n with minimum Hamming distance at least d can be obtained by
application of Turan's theorem to the graph with vertex set {0,1,..,q-1}^n in
which two vertices are joined if and only if their Hamming distance is at least
d. We ge... | 1106.6206v1 |
2011-07-17 | Probabilistic Methods on Erdos Problems | The paper reviews and tries to describe the reference set method, which is a
method of combinatorial optimization that gives upper bounds on parameters. | 1107.3279v17 |
2011-09-12 | Externally-driven transmission and collisions of domain walls in ferromagnetic wires | Analytical multi-domain solutions to the dynamical (Landau-Lifshitz-Gilbert)
equation of a one-dimensional ferromagnet including an external magnetic field
and spin-polarized electric current are found using the Hirota bilinearization
method. A standard approach to solve the Landau-Lifshitz equation (without the
Gilber... | 1109.2465v1 |
2011-10-19 | Current-induced switching in transport through anisotropic magnetic molecules | Anisotropic single-molecule magnets may be thought of as molecular switches,
with possible applications to molecular spintronics. In this paper, we consider
current-induced switching in single-molecule junctions containing an
anisotropic magnetic molecule. We assume that the carriers interact with the
magnetic molecule... | 1110.4270v2 |
2011-10-27 | George Augustus Linhart - as a "widely unknown" thermodynamicist | The name of George Augustus Linhart is in fact "widely unknown". In effect,
he was a Viennese-born USA-American physicist-chemist, partially associated
with the Gilbert Newton Lewis' school of thermodynamics at the University of
California in Berkeley. As a lone small boy, he had arrived (from Austria via
Hamburg) at N... | 1110.6352v1 |
2012-03-29 | Power Allocation over Two Identical Gilbert-Elliott Channels | We study the problem of power allocation over two identical Gilbert-Elliot
communication channels. Our goal is to maximize the expected discounted number
of bits transmitted over an infinite time horizon. This is achieved by choosing
among three possible strategies: (1) betting on channel 1 by allocating all the
power ... | 1203.6630v2 |
2012-04-11 | A short note on spin pumping theory with Landau-Lifshitz-Gilbert equation under quantum fluctuation; necessity for quantization of localized spin | We would like to point out the blind spots of the approach combining the spin
pumping theory proposed by Tserkovnyak et al. with the Landau-Lifshitz-Gilbert
equation; this method has been widely used for interpreting vast experimental
results. The essence of the spin pumping effect is the quantum fluctuation.
Thus, loc... | 1204.2339v1 |
2012-05-22 | Signature of Phase Transitions in the Disordered Quantum Spin Hall State From the Entanglement Spectrum | Of the available classes of insulators which have been shown to contain
topologically non-trivial properties one of the most important is class AII,
which contains systems that possess time-reversal symmetry $T$ with $T^2=-1.$
This class has been the subject of significant attention as it encompasses
non-trivial Z$_2$ ... | 1205.5071v1 |
2012-07-03 | The unusual smoothness of the extragalactic unresolved radio background | If the radio background is coming from cosmological sources, there should be
some amount of clustering due to the large scale structure in the universe.
Simple models for the expected clustering combined with the recent measurement
by ARCADE-2 of the mean extragalactic temperature lead to predicted clustering
levels th... | 1207.0856v1 |
2012-10-12 | Optimal Power Allocation Policy over Two Identical Gilbert-Elliott Channels | We study the fundamental problem of optimal power allocation over two
identical Gilbert-Elliott (Binary Markov) communication channels. Our goal is
to maximize the expected discounted number of bits transmitted over an infinite
time span by judiciously choosing one of the four actions for each time slot:
1) allocating ... | 1210.3609v1 |
2013-03-16 | A convergent linear finite element scheme for the Maxwell-Landau-Lifshitz-Gilbert equation | We consider a lowest-order finite element discretization of the nonlinear
system of Maxwell's and Landau-Lifshitz-Gilbert equations (MLLG). Two
algorithms are proposed to numerically solve this problem, both of which only
require the solution of at most two linear systems per timestep. One of the
algorithms is fully de... | 1303.4009v1 |
2013-03-17 | On the Landau-Lifshitz-Gilbert equation with magnetostriction | To describe and simulate dynamic micromagnetic phenomena, we consider a
coupled system of the nonlinear Landau-Lifshitz-Gilbert equation and the
conservation of momentum equation. This coupling allows to include
magnetostrictive effects into the simulations. Existence of weak solutions has
recently been shown in [Carbo... | 1303.4060v2 |
2013-03-27 | Optimal Power Allocation over Multiple Identical Gilbert-Elliott Channels | We study the fundamental problem of power allocation over multiple
Gilbert-Elliott communication channels. In a communication system with time
varying channel qualities, it is important to allocate the limited transmission
power to channels that will be in good state. However, it is very challenging
to do so because ch... | 1303.6771v1 |
2013-04-29 | Generalized Baumslag-Solitar groups: rank and finite index subgroups | A generalized Baumslag-Solitar (GBS) group is a finitely generated group
acting on a tree with infinite cyclic edge and vertex stabilizers. We show how
to determine effectively the rank (minimal cardinality of a generating set) of
a GBS group; as a consequence, one can compute the rank of the mapping torus of
a finite ... | 1304.7582v2 |
2013-06-02 | On the Riemannian Penrose inequality with charge and the cosmic censorship conjecture | We note an area-charge inequality orignially due to Gibbons: if the outermost
horizon $S$ in an asymptotically flat electrovacuum initial data set is
connected then $|q|\leq r$, where $q$ is the total charge and $r=\sqrt{A/4\pi}$
is the area radius of $S$. A consequence of this inequality is that for
connected black ho... | 1306.0206v3 |
2013-08-19 | A finite element approximation for the stochastic Landau-Lifshitz-Gilbert equation | The stochastic Landau--Lifshitz--Gilbert (LLG) equation describes the
behaviour of the magnetization under the influence of the effective field
consisting of random fluctuations. We first reformulate the equation into an
equation the unknown of which is differentiable with respect to the time
variable. We then propose ... | 1308.3912v2 |
2014-01-14 | Constructions of Pure Asymmetric Quantum Alternant Codes Based on Subclasses of Alternant Codes | In this paper, we construct asymmetric quantum error-correcting codes(AQCs)
based on subclasses of Alternant codes. Firstly, We propose a new subclass of
Alternant codes which can attain the classical Gilbert-Varshamov bound to
construct AQCs. It is shown that when $d_x=2$, $Z$-parts of the AQCs can attain
the classica... | 1401.3215v2 |
2014-03-19 | Numerical integration of the stochastic Landau-Lifshitz-Gilbert equation in generic time-discretisation schemes | We introduce a numerical method to integrate the stochastic
Landau-Lifshitz-Gilbert equation in spherical coordinates for generic
discretization schemes. This method conserves the magnetization modulus and
ensures the approach to equilibrium under the expected conditions. We test the
algorithm on a benchmark problem: t... | 1403.4822v2 |
2014-05-05 | Measuring logarithmic corrections to normal diffusion in infinite-horizon billiards | We perform numerical measurements of the moments of the position of a tracer
particle in a two-dimensional periodic billiard model (Lorentz gas) with
infinite corridors. This model is known to exhibit a weak form of
super-diffusion, in the sense that there is a logarithmic correction to the
linear growth in time of the... | 1405.0975v2 |
2014-05-12 | Efficient Energy-minimization in Finite-Difference Micromagnetics: Speeding up Hysteresis Computations | We implement an efficient energy-minimization algorithm for finite-difference
micromagnetics that proofs especially useful for the computation of hysteresis
loops. Compared to results obtained by time integration of the
Landau-Lifshitz-Gilbert equation, a speedup of up to two orders of magnitude is
gained. The method i... | 1405.2728v3 |
2014-07-01 | Transport properties of Lévy walks: an analysis in terms of multistate processes | Continuous time random walks combining diffusive and ballistic regimes are
introduced to describe a class of L\'evy walks on lattices. By including
exponentially-distributed waiting times separating the successive jump events
of a walker, we are led to a description of such L\'evy walks in terms of
multistate processes... | 1407.0227v2 |
2014-07-26 | Magnetization reversal condition for a nanomagnet within a rotating magnetic field | The reversal condition of magnetization in a nanomagnet under the effect of
rotating magnetic field generated by a microwave is theoretically studied based
on the Landau-Lifshitz-Gilbert equation. In a rotating frame, the microwave
produces a dc magnetic field pointing in the reversed direction, which
energetically sta... | 1407.7095v1 |
2014-09-17 | Aharonov-Bohm Oscillations in a Quasi-Ballistic 3D Topological Insulator Nanowire | In three-dimensional topological insulators (3D TI) nanowires, transport
occurs via gapless surface states where the spin is fixed perpendicular to the
momentum[1-6]. Carriers encircling the surface thus acquire a \pi Berry phase,
which is predicted to open up a gap in the lowest-energy 1D surface subband.
Inserting a ... | 1409.5095v1 |
2014-10-13 | [$α$/Fe] Abundances of Four Outer M 31 Halo Stars | We present alpha element to iron abundance ratios, [$\alpha$/Fe], for four
stars in the outer stellar halo of the Andromeda Galaxy (M 31). The stars were
identified as high-likelihood field halo stars by Gilbert et al. (2012) and lie
at projected distances between 70 and 140 kpc from M 31's center. These are the
first ... | 1410.3475v1 |
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