publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2021-05-16 | Linear stability analysis of the Couette flow for the two dimensional non-isentropic compressible Euler equations | This note is devoted to the linear stability of the Couette flow for the
non-isentropic compressible Euler equations in a domain $\mathbb{T}\times
\mathbb{R}$. Exploiting the several conservation laws originated from the
special structure of the linear system, we obtain a Lyapunov type instability
for the density, the ... | 2105.07395v1 |
2021-05-21 | Effects of ambipolar diffusion on waves in the solar chromosphere | The chromosphere is a partially ionized layer of the solar atmosphere, the
transition between the photosphere where the gas motion is determined by the
gas pressure and the corona dominated by the magnetic field. We study the
effect of partial ionization for 2D wave propagation in a gravitationally
stratified, magnetiz... | 2105.10285v1 |
2021-05-26 | Global Attractor for the Periodic Generalized Korteweg-de Vries Equation Through Smoothing | We establish a smoothing result for the generalized KdV (gKdV) on the torus
with polynomial non-linearity, damping, and forcing that matches the smoothing
level for the gKdV at $H^1$. As a consequence, we establish the existence of a
global attractor for this equation as well as its compactness in
$H^s(\mathbb{T})$, $s... | 2105.13405v2 |
2021-06-01 | On the Well-Posedness of Two Driven-Damped Gross Pitaevskii-Type Models for Exciton-Polariton Condensates | We study the well-posedness of two systems modeling the non-equilibrium
dynamics of pumped decaying Bose-Einstein condensates. In particular, we
present the local theory for rough initial data using the Fourier restricted
norm method introduced by Bourgain. We extend the result globally for initial
data in $L^2$. | 2106.00438v1 |
2021-06-11 | Dynamics and Nonmonotonic Drag for Individually Driven Skyrmions | We examine the motion of an individual skyrmion driven through an assembly of
other skyrmions by a constant or increasing force in the absence of quenched
disorder. The skyrmion behavior is determined by the ratio of the damping and
Magnus terms, as expressed in terms of the intrinsic skyrmion Hall angle. For a
fixed d... | 2106.06093v1 |
2021-06-23 | On generalized damped Klein-Gordon equation with nonlinear memory | In this paper we consider the Cauchy problem for linear dissipative
generalized Klein-Gordon equations with nonlinear memory in the right hand
side. Our goal is to study the effect of this nonlinearity on both the decay
estimates of global solutions as well as the admissible range of the exponent
p. | 2106.12296v1 |
2021-07-21 | Convergence rates for the Heavy-Ball continuous dynamics for non-convex optimization, under Polyak-Łojasiewicz condition | We study convergence of the trajectories of the Heavy Ball dynamical system,
with constant damping coefficient, in the framework of convex and non-convex
smooth optimization. By using the Polyak-{\L}ojasiewicz condition, we derive
new linear convergence rates for the associated trajectory, in terms of
objective functio... | 2107.10123v2 |
2021-08-29 | A note on the energy transfer in coupled differential systems | We study the energy transfer in the linear system $$ \begin{cases} \ddot
u+u+\dot u=b\dot v\\ \ddot v+v-\epsilon \dot v=-b\dot u \end{cases} $$ made by
two coupled differential equations, the first one dissipative and the second
one antidissipative. We see how the competition between the damping and the
antidamping mec... | 2108.12776v1 |
2021-08-29 | Well-posedness and stability for semilinear wave-type equations with time delay | In this paper we analyze a semilinear abstract damped wave-type equation with
time delay. We assume that the delay feedback coefficient is variable in time
and belonging to $L^1_{loc}([0, +\infty)).$ Under suitable assumptions, we show
well-posedness and exponential stability for small initial data. Our strategy
combin... | 2108.12786v1 |
2021-08-30 | Application of Rothe's method to a nonlinear wave equation on graphs | We study a nonlinear wave equation on finite connected weighted graphs. Using
Rothe's and energy methods, we prove the existence and uniqueness of solution
under certain assumption. For linear wave equation on graphs, Lin and Xie
\cite{Lin-Xie} obtained the existence and uniqueness of solution. The main
novelty of this... | 2108.12980v1 |
2021-09-08 | Stabilisation of Waves on Product Manifolds by Boundary Strips | We show that a transversely geometrically controlling boundary damping strip
is sufficient but not necessary for $t^{-1/2}$-decay of waves on product
manifolds. We give a general scheme to turn resolvent estimates for impedance
problems on cross-sections to wave decay on product manifolds. | 2109.03928v1 |
2021-09-10 | Smoothing effect and large time behavior of solutions to nonlinear elastic wave equations with viscoelastic term | The Cauchy problem for a nonlinear elastic wave equations with viscoelastic
damping terms is considered on the 3 dimensional whole space. Decay and
smoothing properties of the solutions are investigated when the initial data
are sufficiently small; and asymptotic profiles as $t \to \infty$ are also
derived. | 2109.04628v3 |
2021-10-04 | Overdamped limit at stationarity for non-equilibrium Langevin diffusions | In this note, we establish that the stationary distribution of a possibly
non-equilibrium Langevin diffusion converges, as the damping parameter goes to
infinity (or equivalently in the Smoluchowski-Kramers vanishing mass limit),
toward a tensor product of the stationary distribution of the corresponding
overdamped pro... | 2110.01238v2 |
2021-10-22 | p-Laplacian wave equations in non-cylindrical domains | This paper is devoted to studying the stability of p-Laplacian wave equations
with strong damping in non-cylindrical domains. The method of proof based on
some estimates for time-varying coefficients rising from moving boundary and a
modified Kormonik inequality. Meanwhile, by selecting appropriate auxiliary
functions,... | 2110.11547v1 |
2021-11-17 | Transverse kink oscillations of inhomogeneous prominence threads: numerical analysis and H$α$ forward modelling | Prominence threads are very long and thin flux tubes which are partially
filled with cold plasma. Observations have shown that transverse oscillations
are frequent in these solar structures. The observations are usually
interpreted as the fundamental kink mode, while the detection of the first
harmonic remains elusive.... | 2111.09036v1 |
2021-11-26 | A novel measurement of marginal Alfvén Eigenmode stability during high power auxiliary heating in JET | The interaction of Alfv\'{e}n Eigenmodes (AEs) and energetic particles is one
of many important factors determining the success of future tokamaks. In JET,
eight in-vessel antennas were installed to actively probe stable AEs with
frequencies ranging 25-250 kHz and toroidal mode numbers $\vert n \vert < 20$.
During the ... | 2111.13569v1 |
2021-12-08 | IGM damping wing constraints on reionisation from covariance reconstruction of two $z\gtrsim7$ QSOs | Bright, high redshift ($z>6$) QSOs are powerful probes of the ionisation
state of the intervening intergalactic medium (IGM). The detection of
Ly$\alpha$ damping wing absorption imprinted in the spectrum of high-z QSOs can
provide strong constraints on the epoch of reionisation (EoR). In this work, we
perform an indepe... | 2112.04091v1 |
2022-01-24 | A blow-up result for a Nakao-type weakly coupled system with nonlinearities of derivative-type | In this paper, we consider a weakly coupled system of a wave and damped
Klein-Gordon equation with nonlinearities of derivative type. We prove a
blow-up result for the Cauchy problem associated with this system for
nonnegative and compactly supported data by means of an iteration argument. | 2201.09462v1 |
2022-03-11 | On the small noise limit in the Smoluchowski-Kramers approximation of nonlinear wave equations with variable friction | We study the validity of a large deviation principle for a class of
stochastic nonlinear damped wave equations, of Klein-Gordon type, in the joint
small mass and small noise limit. The friction term is assumed to be state
dependent. | 2203.05923v2 |
2022-03-28 | Composite Anderson acceleration method with dynamic window-sizes and optimized damping | In this paper, we propose and analyze a set of fully non-stationary Anderson
acceleration algorithms with dynamic window sizes and optimized damping.
Although Anderson acceleration (AA) has been used for decades to speed up
nonlinear solvers in many applications, most authors are simply using and
analyzing the stationa... | 2203.14627v1 |
2022-03-28 | The higher order nonlinear Schrödinger equation with quadratic nonlinearity on the real axis | The initial value problem is considered for a higher order nonlinear
Schr\"odinger equation with quadratic nonlinearity. Results on existence and
uniqueness of weak solutions are obtained. In the case of an effective at
infinity additional damping large-time decay of solutions without any smallness
assumptions is also ... | 2203.14830v1 |
2022-04-03 | Strong Solution of Modified Anistropic 3D-Navier-Stokes Equations | In this paper we study the anisotropic incompressible Navier-Stokes equations
with a logarithm damping $\alpha \log(e+|u|^2)|u|^2u$ in $H^{0.1}$, where we
used new methods, new tools and Fourier analysis. | 2204.01717v2 |
2022-04-28 | Coupling between turbulence and solar-like oscillations: A combined Lagrangian PDF/SPH approach. II - Mode driving, damping and modal surface effect | The first paper of this series established a linear stochastic wave equation
for solar-like p-modes, correctly taking the effect of turbulence thereon into
account. In this second paper, we aim at deriving simultaneous expressions for
the excitation rate, damping rate, and modal surface effect associated with any
given... | 2204.13367v1 |
2022-05-05 | Blow-up solutions of damped Klein-Gordon equation on the Heisenberg group | Inthisnote,weprovetheblow-upofsolutionsofthesemilineardamped Klein-Gordon
equation in a finite time for arbitrary positive initial energy on the
Heisenberg group. This work complements the paper [21] by the first author and
Tokmagambetov, where the global in time well-posedness was proved for the small
energy solutions... | 2205.02705v1 |
2022-05-06 | Quaternion-based attitude stabilization via discrete-time IDA-PBC | In this paper, we propose a new sampled-data controller for stabilization of
the attitude dynamics at a desired constant configuration. The design is based
on discrete-time interconnection and damping assignment (IDA) passivity-based
control (PBC) and the recently proposed Hamiltonian representation of
discrete-time no... | 2205.03086v1 |
2022-05-23 | Extended random-phase-approximation study of fragmentation of giant quadrupole resonance in $^{16}$O | The damping of isoscalar giant quadrupole resonance in $^{16}$O is studied
using extended random-phase-approximation approaches derived from the
time-dependent density-matrix theory. It is pointed out that the effects of
ground-state correlations bring strong fragmentation of quadrupole strength
even if the number of t... | 2205.11654v2 |
2022-06-21 | Nonlinear Compton scattering and nonlinear Breit-Wheeler pair production including the damping of particle states | In the presence of an electromagnetic background plane-wave field, electron,
positron, and photon states are not stable, because electrons and positrons
emit photons and photons decay into electron-positron pairs. This decay of the
particle states leads to an exponential damping term in the probabilities of
single nonl... | 2206.10345v2 |
2022-06-23 | Nonlinear Landau damping for the 2d Vlasov-Poisson system with massless electrons around Penrose-stable equilibria | In this paper, we prove the nonlinear asymptotic stability of the
Penrose-stable equilibria among solutions of the $2d$ Vlasov-Poisson system
with massless electrons. | 2206.11744v2 |
2022-07-25 | Inviscid limit for the compressible Navier-Stokes equations with density dependent viscosity | We consider the compressible Navier-Stokes system describing the motion of a
barotropic fluid with density dependent viscosity confined in a
three-dimensional bounded domain $\Omega$. We show the convergence of the weak
solution to the compressible Navier-Stokes system to the strong solution to the
compressible Euler s... | 2207.12222v1 |
2022-08-25 | Polynomial energy decay rate of a 2D Piezoelectric beam with magnetic effect on a rectangular domain without geometric conditions | In this paper, we investigate the stability of coupled equations modelling a
2D piezoelectric beam with magnetic effect with only one local viscous damping
on a rectangular domain without geometric conditions. We prove that the energy
of the system decays polynomially with the rate 1/t . | 2208.12012v1 |
2022-10-12 | Backward problem for the 1D ionic Vlasov-Poisson equation | In this paper, we study the backward problem for the one-dimensional
Vlasov-Poisson system with massless electrons, and we show the Landau damping
by fixing the asymptotic behaviour of our solution. | 2210.06123v2 |
2022-10-28 | Oblique Quasi-Kink Modes in Solar Coronal Slabs Embedded in an Asymmetric Magnetic Environment: Resonant Damping, Phase and Group Diagrams | There has been considerable interest in magnetoacoustic waves in static,
straight, field-aligned, one-dimensional equilibria where the exteriors of a
magnetic slab are different between the two sides. We focus on trapped,
transverse fundamental, oblique quasi-kink modes in pressureless setups where
the density varies c... | 2210.16091v1 |
2022-11-02 | Data-driven modeling of Landau damping by physics-informed neural networks | Kinetic approaches are generally accurate in dealing with microscale plasma
physics problems but are computationally expensive for large-scale or
multiscale systems. One of the long-standing problems in plasma physics is the
integration of kinetic physics into fluid models, which is often achieved
through sophisticated... | 2211.01021v3 |
2022-11-04 | New Clues About Light Sterile Neutrinos: Preference for Models with Damping Effects in Global Fits | This article reports global fits of short-baseline neutrino data to
oscillation models involving light sterile neutrinos. In the commonly-used 3+1
plane wave model, there is a well-known 4.9$\sigma$ tension between data sets
sensitive to appearance versus disappearance of neutrinos. We find that models
that damp the os... | 2211.02610v5 |
2022-12-07 | A recipe for orbital eccentricity damping in the type-I regime for low viscosity 2D-discs | It is known that gap opening depends on the disc's viscosity; however,
eccentricity damping formulas have only been derived at high viscosities,
ignoring partial gap opening. We aim at obtaining a simple formula to model
$e$-damping of the type-I regime in low viscosity discs, where even small
planets may start opening... | 2212.03608v1 |
2022-12-10 | Linear stabilization for a degenerate wave equation in non divergence form with drift | We consider a degenerate wave equation in one dimension, with drift and in
presence of a leading operator which is not in divergence form. We impose a
homogeneous Dirichlet boundary condition where the degeneracy occurs and a
boundary damping at the other endpoint. We provide some conditions for the
uniform exponential... | 2212.05264v1 |
2022-12-31 | On the stability of shear flows in bounded channels, II: non-monotonic shear flows | We give a proof of linear inviscid damping and vorticity depletion for
non-monotonic shear flows with one critical point in a bounded periodic
channel. In particular, we obtain quantitative depletion rates for the
vorticity function without any symmetry assumptions. | 2301.00288v2 |
2023-03-18 | Spin waves in a superconductor | Spin waves that can propagate in normal and superconducting metals are
investigated. Unlike normal metals, the velocity of spin waves becomes
temperature-dependent in a superconductor. The low frequency spin waves survive
within the narrow region below the superconducting transition temperature. At
low temperatures the... | 2303.10468v1 |
2023-04-07 | Echo disappears: momentum term structure and cyclic information in turnover | We extract cyclic information in turnover and find it can explain the
momentum echo. The reversal in recent month momentum is the key factor that
cancels out the recent month momentum and excluding it makes the echo regress
to a damped shape. Both rational and behavioral theories can explain the
reversal. This study is... | 2304.03437v1 |
2023-04-26 | Plasma echoes in graphene | Plasma echo is a dramatic manifestation of plasma damping process
reversibility. In this paper we calculate temporal and spatial plasma echoes in
graphene in the acoustic plasmon regime when echoes dominate over plasmon
emission. We show an extremely strong spatial echo response and discuss how
electron collisions redu... | 2304.13440v1 |
2023-06-01 | JWST Measurements of Neutral Hydrogen Fractions and Ionized Bubble Sizes at $z=7-12$ Obtained with Ly$α$ Damping Wing Absorptions in 26 Bright Continuum Galaxies | We present volume-averaged neutral hydrogen fractions $x_{\rm \HI}$ and
ionized bubble radii $R_{\rm b}$ measured with Ly$\alpha$ damping wing
absorption of galaxies at the epoch of reionization. We combine JWST/NIRSpec
spectra taken by CEERS, GO-1433, DDT-2750, and JADES programs, and obtain a
sample containing 26 bri... | 2306.00487v2 |
2023-06-20 | New results on controllability and stability for degenerate Euler-Bernoulli type equations | In this paper we study the controllability and the stability for a degenerate
beam equation in divergence form via the energy method. The equation is clamped
at the left end and controlled by applying a shearing force or a damping at the
right end. | 2306.11851v3 |
2023-07-18 | Nonlinear feedback, double bracket dissipation and port control of Lie-Poisson systems | Methods from controlled Lagrangians, double bracket dissipation and
interconnection and damping assignment -- passivity based control (IDA-PBC) are
used to construct nonlinear feedback controls which (asymptotically) stabilize
previously unstable equilibria of Lie-Poisson Hamiltonian systems. The results
are applied to... | 2307.09235v1 |
2023-08-01 | Aerodynamics of the square-back Ahmed body under rainfall conditions | We report an experimental investigation about the aerodynamics of a
simplified road vehicle, the so-called square-back Ahmed body, under rainfall
conditions. A particular emphasis is put on the evolution of the body base
pressure distribution with respect to the operating conditions. It is found
that rainfall significa... | 2308.00276v1 |
2023-09-11 | Study of damped oscillating structures from charged and neutral K-meson electromagnetic form factors data | The damped oscillating structures (OS) were recently revealed in the proton
"effective" form factor (FF) data. For the time being they can be neither
confirmed nor disproved by investigations of timelike data on the individual
proton electric and proton magnetic FFs because their precision and reliability
(especially o... | 2309.05354v1 |
2023-10-31 | Variational principle for a damped, quadratically interacting particle chain with nonconservative forcing | A method for designing variational principles for the dynamics of a possibly
dissipative and non-conservatively forced chain of particles is demonstrated.
Some qualitative features of the formulation are discussed. | 2311.00106v2 |
2023-12-25 | IMEX-RK methods for Landau-Lifshitz equation with arbitrary damping | Magnetization dynamics in ferromagnetic materials is modeled by the
Landau-Lifshitz (LL) equation, a nonlinear system of partial differential
equations. Among the numerical approaches, semi-implicit schemes are widely
used in the micromagnetics simulation, due to a nice compromise between
accuracy and efficiency. At ea... | 2312.15654v1 |
2024-01-30 | Linear stability analysis of the Couette flow for the 2D Euler-Poisson system | This paper is concerned with the linear stability analysis for the Couette
flow of the Euler-Poisson system for both ionic fluid and electronic fluid in
the domain $\bb{T}\times\bb{R}$. We establish the upper and lower bounds of the
linearized solutions of the Euler-Poisson system near Couette flow. In
particular, the ... | 2401.17102v1 |
2024-03-21 | Non-resonant invariant foliations of quasi-periodically forced systems | We show the existence and uniqueness of invariant foliations about invariant
tori in analytic discrete-time dynamical systems. The parametrisation method is
used prove the result. Our theory is a foundational block of data-driven model
order reduction, that can only be carried out using invariant foliations. The
theory... | 2403.14771v1 |
2024-04-03 | Comment on "Machine learning conservation laws from differential equations" | In lieu of abstract, first paragraph reads: Six months after the author
derived a constant of motion for a 1D damped harmonic oscillator [1], a similar
result appeared by Liu, Madhavan, and Tegmark [2, 3], without citing the
author. However, their derivation contained six serious errors, causing both
their method and r... | 2404.02896v1 |
2007-03-01 | Stellar Kinematics in the Complicated Inner Spheroid of M31: Discovery of Substructure Along the Southeastern Minor Axis and its Relationship to the Giant Southern Stream | We present the discovery of a kinematically-cold stellar population along the
SE minor axis of the Andromeda galaxy (M31) that is likely the forward
continuation of M31's giant southern stream. This discovery was made in the
course of an on-going spectroscopic survey of red giant branch (RGB) stars in
M31 using the DEI... | 0703029v3 |
2017-02-26 | Limits on the ultra-bright Fast Radio Burst population from the CHIME Pathfinder | We present results from a new incoherent-beam Fast Radio Burst (FRB) search
on the Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder. Its
large instantaneous field of view (FoV) and relative thermal insensitivity
allow us to probe the ultra-bright tail of the FRB distribution, and to test a
recent claim... | 1702.08040v2 |
2019-04-01 | Astro2020 Science White Paper: Construction of an L* Galaxy: the Transformative Power of Wide Fields for Revealing the Past, Present and Future of the Great Andromeda System | The Great Andromeda Galaxy (M31) is the nexus of the near-far galaxy
evolution connection and a principal data point for near-field cosmology. Due
to its proximity (780 kpc), M31 can be resolved into individual stars like the
Milky Way (MW). Unlike the MW, we have the advantage of a global view of M31,
enabling M31 to ... | 1904.01074v1 |
2021-09-28 | Diving Beneath the Sea of Stellar Activity: Chromatic Radial Velocities of the Young AU Mic Planetary System | We present updated radial-velocity (RV) analyses of the AU Mic system. AU Mic
is a young (22 Myr) early M dwarf known to host two transiting planets -
$P_{b}\sim8.46$ days, $R_{b}=4.38_{-0.18}^{+0.18}\ R_{\oplus}$,
$P_{c}\sim18.86$ days, $R_{c}=3.51_{-0.16}^{+0.16}\ R_{\oplus}$. With visible
RVs from CARMENES-VIS, CHIR... | 2109.13996v1 |
2022-03-04 | Scaling K2. V. Statistical Validation of 60 New Exoplanets From K2 Campaigns 2-18 | The NASA K2 mission, salvaged from the hardware failures of the Kepler
telescope, has continued Kepler's planet-hunting success. It has revealed
nearly 500 transiting planets around the ecliptic plane, many of which are the
subject of further study, and over 1000 additional candidates. Here we present
the results of an... | 2203.02087v2 |
1994-06-27 | Reverberation mapping of active galactic nuclei : The SOLA method for time-series inversion | In this paper a new method is presented to find the transfer function of the
broad-line region in active galactic nuclei. The subtractive optimally
localized averages (SOLA) method is a modified version of the Backus-Gilbert
method and is presented as an alternative to the more often used
maximum-entropy method. The SO... | 9406070v1 |
1997-06-20 | Rejection of the Binary Broad-Line Region Interpretation of Double-Peaked Emission Lines in Three Active Galactic Nuclei | It has been suggested that the peculiar double-peaked Balmer lines of certain
broad-line radio galaxies come from individual broad-line regions associated
with the black holes of a supermassive binary. We continue to search for
evidence of the radial velocity variations characteristic of a double-lined
spectroscopic bi... | 9706222v2 |
1999-08-13 | Infrared Spectroscopy of the High Redshift Radio Galaxy MRC~2025-218 and a Neighboring Extremely Red Galaxy | This paper presents infrared spectra taken with the newly commissioned
NIRSPEC spectrograph on the Keck Telescope of the High Redshift Radio Galaxy
MRC 2025-218 (z=2.630) and an extremely red galaxy (R-K > 6 mag) 9'' away.
These observations represent the deepest infrared spectra of a radio galaxy to
date and have allo... | 9908153v1 |
2000-01-11 | 2 micron Spectroscopy within 0.3 arcseconds of SgrA* | We present moderate (R~$\approx$~2,700) and high resolution
(R~$\approx$~22,000) 2.0$-$2.4 \micron\ spectroscopy of the central 0.1 square
arcseconds of the Galaxy obtained with NIRSPEC, the facility near-infrared
spectrometer for the Keck II telescope. The composite spectra do not have any
features attributable to the... | 0001171v1 |
2000-02-17 | Discovery of an Obscured Broad Line Region in the High Redshift Radio Galaxy MRC 2025-218 | This paper presents infrared spectra taken with the newly commissioned
NIRSPEC spectrograph on the Keck II Telescope of the High Redshift Radio Galaxy
MRC 2025-218 (z=2.63) These observations represent the deepest infrared spectra
of a radio galaxy to date and have allowed for the detection of Hbeta, [OIII]
(4959/5007)... | 0002335v1 |
2000-02-26 | Hot Stars and Cool Clouds: The Photodissociation Region M16 | We present high-resolution spectroscopy and images of a photodissociation
region (PDR) in M16 obtained during commissioning of NIRSPEC on the Keck II
telescope. PDRs play a significant role in regulating star formation, and M16
offers the opportunity to examine the physical processes of a PDR in detail. We
simultaneous... | 0002491v1 |
2000-02-28 | The Rest-Frame Optical Spectrum of MS 1512-cB58 | Moderate resolution, near-IR spectroscopy of MS1512-cB58 is presented,
obtained during commissioning of the the Near IR Spectrometer (NIRSPEC) on the
Keck II telescope. The strong lensing of this z=2.72 galaxy by the foreground
cluster MS1512+36 makes it the best candidate for detailed study of the
rest-frame optical p... | 0002508v1 |
2000-03-06 | The Sunyaev-Zel'dovich Effect in Abell 370 | We present interferometric measurements of the Sunyaev-Zel'dovich (SZ) effect
towards the galaxy cluster Abell 370. These measurements, which directly probe
the pressure of the cluster's gas, show the gas distribution to be strongly
aspherical, as do the x-ray and gravitational lensing observations. We
calculate the cl... | 0003085v1 |
2000-12-04 | Galaxy Cluster Gas Mass Fractions from Sunyaev-Zel'dovich Effect Measurements: Constraints on Omega_M | Using sensitive centimeter-wave receivers mounted on the Owens Valley Radio
Observatory and Berkeley-Illinois-Maryland-Association millimeter arrays, we
have obtained interferometric measurements of the Sunyaev-Zel'dovich (SZ)
effect toward massive galaxy clusters. We use the SZ data to determine the
pressure distribut... | 0012067v1 |
2001-01-02 | Science Prospects for SPI | After the recent beautiful results on gamma-ray lines obtained with CGRO, the
INTEGRAL mission with the imaging-spectrometer SPI will set the next milestone,
combining improved sensitivity and angular resolution with a considerable
increase in spectral resolution. SPI is expected to provide significant new
information ... | 0101018v1 |
2002-08-07 | Massive Stars in the Arches Cluster | We present and use new spectra and narrow-band images, along with previously
published broad-band images, of stars in the Arches cluster to extract
photometry, astrometry, equivalent width, and velocity information. The data
are interpreted with a wind/atmosphere code to determine stellar temperatures,
luminosities, ma... | 0208145v1 |
2003-01-31 | Ultraviolet spectroscopy of narrow coronal mass ejections | We present Ultraviolet Coronagraph Spectrometer (UVCS) observations of 5
narrow coronal mass ejections (CMEs) that were among 15 narrow CMEs originally
selected by Gilbert et al. (2001). Two events (1999 March 27, April 15) were
"structured", i.e. in white light data they exhibited well defined interior
features, and t... | 0301649v1 |
2003-02-05 | Cluster Sunyaev-Zeldovich Effect Scaling Relations | X-ray observations of an "entropy floor" in nearby groups and clusters of
galaxies offer evidence that important non-gravitational processes, such as
radiative cooling and/or "preheating", have strongly influenced the evolution
of the intracluster medium (ICM). We examine how the presence of an entropy
floor modifies t... | 0302087v1 |
2003-03-20 | The SZ Effect Signature of Excess Entropy in Distant, Massive Clusters | Studies of cluster X-ray scaling relations have led to suggestions that
non-gravitational processes, e.g., radiative cooling and/or "preheating", have
significantly modified the entropy of the intracluster medium (ICM). For the
first time, we test this hypothesis through a comparison of predicted thermal
Sunyaev-Zeldov... | 0303451v2 |
2005-08-01 | Transit Photometry of the Core-Dominated Planet HD 149026b | We report g, V, and r photometric time series of HD 149026 spanning predicted
times of transit of the Saturn-mass planetary companion, which was recently
discovered by Sato and collaborators. We present a joint analysis of our
observations and the previously reported photometry and radial velocities of
the central star... | 0508051v1 |
2005-10-28 | Photoionized HBeta Emission in NGC 5548: It Breathes! | Emission-line regions in active galactic nuclei and other photoionized
nebulae should become larger in size when the ionizing luminosity increases.
This 'breathing' effect is observed for the Hbeta emission in NGC 5548 by using
Hbeta and optical continuum lightcurves from the 13-year 1989-2001 AGN Watch
monitoring camp... | 0510800v1 |
2006-07-25 | The Transit Light Curve (TLC) Project. I. Four Consecutive Transits of the Exoplanet XO-1b | We present RIz photometry of four consecutive transits of the newly
discovered exoplanet XO-1b. We improve upon the estimates of the transit
parameters, finding the planetary radius to be R_P = 1.184 +0.028/-0.018
R_Jupiter and the stellar radius to be R_S = 0.928 +0.018/-0.013 R_Sun,
assuming a stellar mass of M_S = 1... | 0607571v1 |
2006-09-12 | TrES-2: The First Transiting Planet in the Kepler Field | We announce the discovery of the second transiting hot Jupiter discovered by
the Trans-atlantic Exoplanet Survey. The planet, which we dub TrES-2, orbits
the nearby star GSC 03549-02811 every 2.47063 days. From high-resolution
spectra, we determine that the star has T_eff = 5960 +/- 100 K and log(g) = 4.4
+/- 0.2, impl... | 0609335v1 |
2006-10-19 | Precise Radius Estimates for the Exoplanets WASP-1b and WASP-2b | We present precise z-band photometric time series spanning times of transit
of the two exoplanets recently discovered by the SuperWASP collaboration. We
find planetary radii of 1.44 +/- 0.08 R_J and 1.04 +/- 0.06 R_J for WASP-1b and
WASP-2b, respectively. These error estimates include both random errors in the
photomet... | 0610589v1 |
2007-02-16 | The Extended Star Formation History of the Andromeda Spheroid at Twenty One Kiloparsecs on the Minor Axis | Using the HST ACS, we have obtained deep optical images of a southeast
minor-axis field in the Andromeda Galaxy, 21 kpc from the nucleus. In both star
counts and metallicity, this field represents a transition zone between the
metal-rich, highly-disturbed inner spheroid that dominates within 15 kpc and
the metal-poor, ... | 0702448v1 |
2007-02-23 | Discovery of Andromeda XIV: A Dwarf Spheroidal Dynamical Rogue in the Local Group? | In the course of our survey of the outer halo of the Andromeda Galaxy we have
discovered a remote, possible satellite of that system at a projected 162 kpc
(11.7 degrees) radius. The fairly elongated (0.31 +/- 0.09 ellipticity) dwarf
can be fit with a King profile of 1.07 kpc (d/784 kpc) limiting radius, where
the sate... | 0702635v2 |
1998-05-27 | Survival Analysis, Master Equation, Efficient Simulation of Path-Related Quantities, and Hidden State Concept of Transitions | This paper presents and derives the interrelations between survival analysis
and master equation. Survival analysis deals with modeling the transitions
between succeeding states of a system in terms of hazard rates. Questions
related with this are the timing and sequencing of the states of a time series.
The frequency ... | 9805361v1 |
1999-09-09 | Micromagnetic simulations of thermally activated magnetization reversal of nanoscale magnets | Numerical integration of a stochastic Landau-Lifshitz-Gilbert equation is
used to study dynamic processes in single-domain nanoscale magnets at nonzero
temperatures. Special attention is given to including thermal fluctuations as a
Langevin term, and the Fast Multipole Method is used to calculate dipole-dipole
interact... | 9909136v2 |
2000-10-12 | Thermal Magnetization Reversal in Arrays of Nanoparticles | The results of large-scale simulations investigating the dynamics of
magnetization reversal in arrays of single-domain nanomagnets after a rapid
reversal of the applied field at nonzero temperature are presented. The
numerical micromagnetic approach uses the Landau-Lifshitz-Gilbert equation
including contributions from... | 0010184v2 |
2001-12-12 | High Magnetic Field NMR Studies of LiVGe$_2$O$_6$, a quasi 1-D Spin $S = 1$ System | We report $^{7}$Li pulsed NMR measurements in polycrystalline and single
crystal samples of the quasi one-dimensional S=1 antiferromagnet
LiVGe$_2$O$_6$, whose AF transition temperature is $T_{\text{N}}\simeq 24.5$ K.
The field ($B_0$) and temperature ($T$) ranges covered were 9-44.5 T and
1.7-300 K respectively. The m... | 0112203v1 |
2003-10-07 | Endogenous Versus Exogenous Shocks in Complex Networks: an Empirical Test Using Book Sale Ranking | Are large biological extinctions such as the Cretaceous/Tertiary KT boundary
due to a meteorite, extreme volcanic activity or self-organized critical
extinction cascades? Are commercial successes due to a progressive reputation
cascade or the result of a well orchestrated advertisement? Determining the
chain of causali... | 0310135v2 |
2004-08-18 | Irreversible spin-transfer and magnetization reversal under spin-injection | In the context of spin electronics, the two spin-channel model assumes that
the spin carriers are composed of two distinct populations: the conduction
electrons of spin up, and the conduction electrons of spin down. In order to
distinguish the paramagnetic and ferromagnetic contributions in spin injection,
we describe ... | 0408410v1 |
2004-12-02 | Dielectric resonances in disordered media | Binary disordered systems are usually obtained by mixing two ingredients in
variable proportions: conductor and insulator, or conductor and
super-conductor. and are naturally modeled by regular bi-dimensional or
tri-dimensional lattices, on which sites or bonds are chosen randomly with
given probabilities. In this arti... | 0412061v1 |
2005-01-12 | Current induced magnetization switching in exchange biased spin-valves for CPP-GMR heads | In contrast to earlier studies performed on simple Co/Cu/Co sandwiches, we
have investigated spin transfer effects in complex spin-valve pillars with a
diameter of 130nm developed for current-perpendicular to the plane (CPP)
magneto-resistive heads. The structure of the samples included an exchange
biased synthetic pin... | 0501281v1 |
2005-12-20 | Theory of Spin Torque in a nanomagnet | We present a complete theory of the spin torque phenomena in a ultrasmall
nanomagnet coupled to non-collinear ferromagnetic electrodes through tunnelling
junctions. This model system can be described by a simple microscopic model
which captures many physical effects characteristic of spintronics: tunneling
magneto resi... | 0512508v1 |
2005-09-19 | Capacity-Achieving Codes with Bounded Graphical Complexity on Noisy Channels | We introduce a new family of concatenated codes with an outer low-density
parity-check (LDPC) code and an inner low-density generator matrix (LDGM) code,
and prove that these codes can achieve capacity under any memoryless
binary-input output-symmetric (MBIOS) channel using maximum-likelihood (ML)
decoding with bounded... | 0509062v3 |
2006-07-20 | List decoding of noisy Reed-Muller-like codes | First- and second-order Reed-Muller (RM(1) and RM(2), respectively) codes are
two fundamental error-correcting codes which arise in communication as well as
in probabilistically-checkable proofs and learning. In this paper, we take the
first steps toward extending the quick randomized decoding tools of RM(1) into
the r... | 0607098v2 |
1994-05-31 | The Behavior of a Spherical Hole in an Infinite Uniform Universe | In this paper, the behavior of a spherical hole in an otherwise infinite and
uniform universe is investigated. First, the Newtonian theory is developed. The
concept of negative gravity, an outward gravitational force acting away from
the center of the spherical hole, is presented, and the resulting expansion of
the hol... | 9405075v1 |
2002-11-21 | SuSpect: a Fortran Code for the Supersymmetric and Higgs Particle Spectrum in the MSSM | We present the Fortran code SuSpect version 2.3, which calculates the
Supersymmetric and Higgs particle spectrum in the Minimal Supersymmetric
Standard Model (MSSM). The calculation can be performed in constrained models
with universal boundary conditions at high scales such as the gravity (mSUGRA),
anomaly (AMSB) or g... | 0211331v2 |
2004-11-04 | Theoretical and Experimental Analysis of a Randomized Algorithm for Sparse Fourier Transform Analysis | We analyze a sublinear RAlSFA (Randomized Algorithm for Sparse Fourier
Analysis) that finds a near-optimal B-term Sparse Representation R for a given
discrete signal S of length N, in time and space poly(B,log(N)), following the
approach given in \cite{GGIMS}. Its time cost poly(log(N)) should be compared
with the supe... | 0411102v2 |
2006-12-04 | Krull dimension and deviation in certain parafree groups | Hanna Neumann asked whether it was possible for two non-isomorphic residually
nilpotent finitely generated (fg) groups, one of them free, to share the lower
central sequence. Gilbert Baumslag answered the question in the affirmative and
thus gave rise to parafree groups. A group G is termed parafree of rank n if it
is ... | 0612102v2 |
2004-07-27 | Domain wall dynamics driven by adiabatic spin transfer torques | In a first approximation, known as the adiabatic process, the direction of
the spin polarization of currents is parallel to the local magnetization vector
in a domain wall. Thus the spatial variation of the direction of the spin
current inside the domain wall results in an adiabatical spin transfer torque
on the magnet... | 0407064v1 |
1997-02-07 | Two-pion correlations in Au+Au collisions at 10.8 GeV/c per nucleon | Two-particle correlation functions for positive and negative pions have been
measured in Au+Au collisions at 10.8~GeV/c per nucleon. The data were analyzed
using one- and three-dimensional correlation functions. From the results of the
three-dimensional fit the phase space density of pions was calculated. It is
consist... | 9702008v1 |
2007-01-30 | Huddling behavior in emperor penguins : dynamics of huddling | Although huddling was shown to be the key by which emperor penguins
(Aptenodytes forsteri) save energy and sustain their breeding fast during the
Antarctic winter, the intricacies of this social behavior have been poorly
studied. We recorded abiotic variables with data loggers glued to the feathers
of eight individuall... | 0701051v1 |
2003-10-14 | The Minimum Distance Problem for Two-Way Entanglement Purification | Entanglement purification takes a number of noisy EPR pairs and processes
them to produce a smaller number of more reliable pairs. If this is done with
only a forward classical side channel, the procedure is equivalent to using a
quantum error-correcting code (QECC). We instead investigate entanglement
purification pro... | 0310097v4 |
2005-06-02 | Enhanced algorithms for Local Search | Let G=(V,E) be a finite graph, and f:V->N be any function. The Local Search
problem consists in finding a local minimum of the function f on G, that is a
vertex v such that f(v) is not larger than the value of f on the neighbors of v
in G. In this note, we first prove a separation theorem slightly stronger than
the one... | 0506019v1 |
2007-09-27 | Predictions of the causal entropic principle for environmental conditions of the universe | The causal entropic principle has been proposed as a superior alternative to
the anthropic principle for understanding the magnitude of the cosmological
constant. In this approach, the probability to create observers is assumed to
be proportional to the entropy production \Delta S in a maximal causally
connected region... | 0709.4443v2 |
2007-10-24 | The Impact of Halo Properties, Energy Feedback and Projection Effects on the Mass-SZ Flux Relation | We present a detailed analysis of the intrinsic scatter in the integrated SZ
effect - cluster mass (Y-M) relation, using semi-analytic and simulated cluster
samples. Specifically, we investigate the impact on the Y-M relation of energy
feedback, variations in the host halo concentration and substructure
populations, an... | 0710.4555v1 |
2007-10-31 | Spin-Torque Driven Magnetization Dynamics: Micromagnetic Modelling | In this paper we present an overview of recent progress made in the
understanding of the spin-torque induced magnetization dynamics in nanodevices
using mesoscopic micromagnetic simulations. We first specify how a spin-torque
term may be added to the usual Landau-Lifshitz-Gilbert equation of
magnetization motion and de... | 0710.5924v1 |
2007-11-19 | The Kohn-Sham system in one-matrix functional theory | A system of electrons in a local or nonlocal external potential can be
studied with 1-matrix functional theory (1MFT), which is similar to density
functional theory (DFT) but takes the one-particle reduced density matrix
(1-matrix) instead of the density as its basic variable. Within 1MFT, Gilbert
derived [PRB 12, 2111... | 0711.2996v1 |
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