publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2024-01-30 | Poynting-Robertson damping of laser beam driven lightsails | Lightsails using Earth-based lasers for propulsion require passive
stabilization to stay within the beam. This can be achieved through the sail's
scattering properties, creating optical restoring forces and torques. Undamped
restoring forces produce uncontrolled oscillations, which could jeopardize the
mission, but it ... | 2401.16924v1 |
2024-02-29 | The Equation of Motion for Taut-Line Buzzers | Equations of motion are developed for the oscillatory rotation of a disk
suspended between twisted strings kept under tension by a hanging mass, to
which additional forces may be applied. In the absence of forcing, damped
harmonic oscillations are observed to decay with an exponential time envelope
for two different st... | 2402.19285v1 |
2024-03-08 | A design methodology for nonlinear oscillator chains enabling energy localization tuning and soliton stability enhancement with optimal damping | In this paper, the vibration energy localization in coupled nonlinear
oscillators is investigated, based on the creation of standing solitons. The
main objective is to establish a design methodology for mechanical lattices
using the Nonlinear Schr\"odinger Equation (NLSE) as a guide strategy, even in
the presence of da... | 2403.05176v1 |
2024-03-08 | Damping Obliquities of Hot Jupiter Hosts by Resonance Locking | When orbiting hotter stars, hot Jupiters are often highly inclined relative
to their host star equator planes. By contrast, hot Jupiters orbiting cooler
stars are more aligned. Prior attempts to explain this correlation between
stellar obliquity and effective temperature have proven problematic. We show
how resonance l... | 2403.05616v1 |
1996-05-06 | A Keck HIRES Investigation of the Metal Abundances and Kinematics of Three Damped Lya Systems Toward Q2206-199 | We present high resolution, high SNR spectra of the QSO Q2206-199 obtained
with HIRES on the 10m W.M. Keck Telescope. Our analysis focuses on the two
previously identified damped \lya systems found at $z=1.920$ and $z=2.076$. For
each system, we measure accurate abundances. The $z=1.920$ system exhibits the
highest met... | 9605021v2 |
1996-09-09 | The Population of Damped Lyman-alpha and Lyman Limit Systems in the Cold Dark Matter Model | Lyman limit and damped Lyman-alpha absorption systems probe the distribution
of collapsed, cold gas at high redshift. Numerical simulations that incorporate
gravity and gas dynamics can predict the abundance of such absorbers in
cosmological models. We develop a semi-analytical method to correct the
numerical predictio... | 9609072v1 |
1998-05-22 | Protogalactic Disk Models of Damped Lya Kinematics | We present new observational results on the kinematics of the damped lya
systems. Our full sample is now comprised of 31 low-ion profiles and exhibits
similar characteristics to the sample from Paper I. The primary exception is
that the new distribution of velocity widths includes values out to a maximum
of nearly 300 ... | 9805293v1 |
2000-05-05 | UVES observations of QSO 0000-2620: oxygen and zinc abundances in the Damped Ly-alpha galaxy at z_abs=3.3901 | Observations of the QSO 0000-2620 with UVES spectrograph at the 8.2m ESO
KUEYEN telescope are used for abundance analysis of the damped Ly-alpha system
at z_{abs}=3.3901. Several Oxygen lines are identified in the Ly_alpha forest
and a measure for the oxygen abundance is obtained at [O/H]=-1.85 +/- 0.1 by
means of the ... | 0005098v1 |
2002-02-06 | The UCSD HIRES/KeckI Damped Lya Abundance Database III. An Empirical Study of Photoionization in the Damped Lya System Toward GB1759+7539 | We investigate the ionization state of the damped Lya system at z=2.62 toward
GB1759+7539 through an analysis of ionic ratios sensitive to photoionization:
ArI/SII, FeIII/FeII, NII/NI, AlIII/AlII. Approximately half of the metals arise
in a mostly neutral velocity component with HI/H > 0.9, based on FeIII/FeII <
0.013.... | 0202140v1 |
2009-09-26 | Damped and sub-damped Lyman-? absorbers in z > 4 QSOs | We present the results of a survey for damped (DLA, log N(H I) > 20.3) and
sub-damped Lyman-? systems (19.5 < log N(H I) < 20.3) at z > 2.55 along the
lines-of-sight to 77 quasars with emission redshifts in the range 4 < zem <
6.3. Intermediate resolution (R ? 4300) spectra have been obtained with the
Echellette Spectr... | 0909.4839v2 |
2011-05-19 | Tidal dissipation compared to seismic dissipation: in small bodies, in earths, and in superearths | While the seismic quality factor and phase lag are defined solely by the bulk
properties of the mantle, their tidal counterparts are determined both by the
bulk properties and self-gravitation of a body as a whole. For a qualitative
estimate, we model the body with a homogeneous sphere and express the tidal
phase lag t... | 1105.3936v12 |
2014-10-07 | The Effect of Nonlinear Landau Damping on Ultrarelativistic Beam Plasma Instabilities | Very-high energy gamma-rays from extragalactic sources pair-produce off of
the extragalactic background light, yielding an electron-positron pair beam.
This pair beam is unstable to various plasma instabilities, especially the
"oblique" instability, which can be the dominant cooling mechanism for the
beam. However, rec... | 1410.3797v2 |
2017-01-24 | Influence of interlayer coupling on the spin torque driven excitations in a spin torque oscillator | The influence of dynamic interlayer interactions on the spin torque driven
and damped excitations are illustrated for a three layer macrospin model system
that corresponds to a standard spin-torque oscillator. The free layer and a
synthetic antiferromagnetic (SyF) pinned layer of the spin-torque oscillator
are in-plane... | 1701.06787v1 |
2017-03-21 | Using rf voltage induced ferromagnetic resonance to study the spin-wave density of states and the Gilbert damping in perpendicularly magnetized disks | We study how the shape of the spinwave resonance lines in rf-voltage induced
FMR can be used to extract the spinwave density of states and the damping
within the precessing layer in nanoscale tunnel junctions that possess
perpendicular anisotropy. We work with a field applied along the easy axis to
preserve the uniaxia... | 1703.07310v2 |
2017-04-07 | Global Alfven Eigenmodes in the H-1 heliac | Recent upgrades in H-1 power supplies have enabled the operation of the H-1
experiment at higher heating powers than previously attainable. A heating power
scan in mixed hydrogen/helium plasmas reveals a change in mode activity with
increasing heating power. At low power (<50 kW) modes with beta-induced Alfven
eigenmod... | 1704.02089v1 |
2017-11-30 | Scalar dark matter interpretation of the DAMPE data with U(1) gauge interactions | Recently, DAMPE experiment released the new measurement of the total cosmic
$e^+e^-$ flux between 25 GeV and 4.6 TeV which indicates a spectral softening
at around 0.9 TeV and a tentative peak at around 1.4 TeV. We utilize the scalar
dark matter (DM) annihilation scenario to explain the DAMPE peak by extending
$G_{SM}\... | 1711.11452v2 |
2017-12-14 | Scalar dark matter explanation of the DAMPE data in the minimal Left-Right symmetric model | Left-Right symmetric model (LRSM) has been an attractive extension of the
Standard Model (SM) which can address the origin of parity violation in the SM
electroweak (EW) interactions, generate tiny neutrino masses, accommodate dark
matter (DM) candidates and provide a natural framework for baryogenesis through
leptogen... | 1712.05351v3 |
2018-02-20 | The chemical connection between damped Lyman-α systems and Local Group dwarf galaxies | Abundances of the volatile elements S and Zn have now been measured in around
80 individual stars in the Sculptor dwarf spheroidal galaxy, covering the
metallicity range $-2.4\leq\text{[Fe/H]}\leq-0.9$. These two elements are of
particular interest as they are not depleted onto dust in gas, and their ratio,
[S/Zn], has... | 1802.07325v5 |
2019-01-12 | GW170817 implications on the frequency and damping time of f-mode oscillations of neutron stars | Within a minimum model for neutron stars consisting of nucleons, electrons
and muons at $\beta$-equilibrium using about a dozen Equation of States (EOSs)
from microscopic nuclear many-body theories and 40,000 EOSs randomly generated
using an explicitly isospin-dependent parametric EOS model for high-density
neutron-ric... | 1901.03779v2 |
2019-01-27 | An introductory guide to fluid models with anisotropic temperatures Part 2 -- Kinetic theory, Padé approximants and Landau fluid closures | In Part 2 of our guide to collisionless fluid models, we concentrate on
Landau fluid closures. These closures were pioneered by Hammett and Perkins and
allow for the rigorous incorporation of collisionless Landau damping into a
fluid framework. It is Landau damping that sharply separates traditional fluid
models and co... | 1901.09360v2 |
2019-01-28 | Revisit of non-linear Landau damping for electrostatic instability driven by blazar-induced pair beams | We revisit the effect of non-linear Landau (NL) damping on the electrostatic
instability of blazar-induced pair beams, using a realistic pair-beam
distribution. We employ a simplified 2D model in ${\bf k}$-space to study the
evolution of the electric-field spectrum and to calculate the relaxation time
of the beam. We d... | 1901.09640v3 |
2019-08-08 | Annihilation of topological solitons in magnetism with spin wave burst finale: The role of nonequilibrium electrons causing nonlocal damping and spin pumping over ultrabroadband frequency range | We not only reproduce burst of short-wavelength spin waves (SWs) observed in
recent experiment [S. Woo et al., Nat. Phys. 13, 448 (2017)] on
magnetic-field-driven annihilation of two magnetic domain walls (DWs) but,
furthermore, we predict that this setup additionally generates highly unusual}
pumping of electronic spi... | 1908.03194v5 |
2019-11-22 | Role of Element-Specific Damping on the Ultrafast, Helicity-Independent All-Optical Switching Dynamics in Amorphous (Gd,Tb)Co Thin Films | Ultrafast control of the magnetization in ps timescales by fs laser pulses
offers an attractive avenue for applications such as fast magnetic devices for
logic and memory. However, ultrafast helicity-independent all-optical switching
(HI-AOS) of the magnetization has thus far only been observed in Gd-based,
ferrimagnet... | 1911.09803v3 |
2020-09-14 | Large field-like torque in amorphous Ru2Sn3 originated from the intrinsic spin Hall effect | We investigated temperature dependent current driven spin-orbit torques in
magnetron sputtered Ru2Sn3 (4 and 10 nm) /Co20Fe60B20 (5 nm) layered structures
with in-plane magnetic anisotropy. The room temperature damping-like and
field-like spin torque efficiencies of the amorphous Ru2Sn3 films were measured
to be 0.14 +... | 2009.06711v2 |
2021-01-12 | Phase Retrieval using Expectation Consistent Signal Recovery Algorithm based on Hypernetwork | Phase retrieval (PR) is an important component in modern computational
imaging systems. Many algorithms have been developed over the past
half-century. Recent advances in deep learning have introduced new
possibilities for a robust and fast PR. An emerging technique called deep
unfolding provides a systematic connectio... | 2101.04348v2 |
2024-03-22 | Investigating the Relationship between Simulation Parameters and Flow Variables in Simulating Atmospheric Gravity Waves in Wind Energy Applications | Wind farms, particularly offshore clusters, are becoming larger than ever
before. Besides influencing wind farms and local meteorology downstream, large
wind farms can trigger atmospheric gravity waves in the inversion layer and the
free atmosphere aloft. Wind farm-induced gravity waves can cause adverse
pressure gradi... | 2403.18863v1 |
2012-03-21 | On a New Method of Storing a Variable Size Array | This paper introduces a new data structure, log_vector, with the following
properties: constant time random access to individual elements; constant time
element addition to the end; constant time element removal from the end;
constant time empty data structure creation; amortized constant space per
individual elements;... | 1203.4836v1 |
2022-10-24 | The AFLT $q$-Morris constant term identity | It is well-known that the Selberg integral is equivalent to the Morris
constant term identity. More generally, Selberg type integrals can be turned
into constant term identities for Laurent polynomials. In this paper, by
extending the Gessel--Xin method of the Laurent series proof of constant term
identities, we obtain... | 2210.13245v1 |
2010-01-10 | Non-expanding universe: a cosmological system of units | The product of two empirical constants, the dimensionless fine structure
constant and the von Klitzing constant (an electrical resistance), turns out to
be an exact dimensionless number. Then the accuracy and cosmological time
variation (if any) of these two constants are tied. Also this product defines a
natural unit ... | 1001.1561v1 |
2010-08-10 | Linear Size Optimal q-ary Constant-Weight Codes and Constant-Composition Codes | An optimal constant-composition or constant-weight code of weight $w$ has
linear size if and only if its distance $d$ is at least $2w-1$. When $d\geq
2w$, the determination of the exact size of such a constant-composition or
constant-weight code is trivial, but the case of $d=2w-1$ has been solved
previously only for b... | 1008.1611v1 |
2007-02-15 | Constant Mean Curvature n-noids with Platonic Symmetries | Constant Mean Curvature n-noids with Platonic Symmetries | 0702469v1 |
2016-07-08 | Alternative set of defining constants for redefinition of four SI units | We discuss different sets of defining constants, fixed values of which are
considered in connection with the transition to new definitions of four SI
units (the kilogram, the mole, the ampere, and the kelvin). The notion of
constant's order in a given system of units is suggested. We propose an
alternative set of fixed... | 1607.02280v2 |
2021-11-16 | New geometric constants of isosceles orthogonal type | Based on the parallelogram law and isosceles orthogonality, we define a new
orthogonal geometric constant. We first discuss some basic properties of this
new constant. Next, we consider the relation between the constant and the
uniformly non-square property. Moreover, a generalized constant is also
introduced and some ... | 2111.08392v2 |
2021-12-11 | Inscribed triangles in the unit sphere and a new class of geometric constants | We will introduce a new geometric constant GL(X) based on the constant H(X)
proposed by Gao. We first further survey the constant H(X) and discuss some of
the properties of this constant that have not yet been discovered. Next, we
focus on a new constant GL(X) along with some of its basic properties. In
addition, we sh... | 2112.05922v1 |
2004-10-12 | Atomic Clocks and Constraints on Variations of Fundamental Constants | We consider an application of precision frequency measurements to searches
for possible time variations of the fundamental physical constants. Current
laboratory constraints on variations of the fine structure constant alpha and
other fundamental constants are presented. | 0410074v1 |
2009-11-04 | On the best constant of Hardy-Sobolev Inequalities | We obtain the sharp constant for the Hardy-Sobolev inequality involving the
distance to the origin. This inequality is equivalent to a limiting
Caffarelli-Kohn-Nirenberg inequality. In three dimensions, in certain cases the
sharp constant coincides with the best Sobolev constant. | 0911.0948v1 |
2010-01-01 | On Apery's Constant and Catalan's Constant | In this paper, Riemann's Zeta function with odd positive integer argument is
represented as an infinite summation of integer powers of $\pi$ with rational
coefficients. Specific values for Apery's Constant and Catalan's Constant are
then derived. | 1001.0248v2 |
2019-04-23 | Two-field constant roll inflation | Starting from the idea of realising constant roll inflation in string theory
we develop the constant roll formalism for two scalar fields. We derive the
two-field potential which is compatible with a constant roll regime and discuss
possible applications to string-models. | 1904.10241v1 |
2023-07-16 | When do Fermat constants completely determine Clairaut constants for branching geodesics on a surface of revolution? | We prove that Fermat constants do not completely determine Clairaut constants
for three branching geodesics that meet at the weighted Fermat-Torricelli point
on a surface of revolution, except the case of a standard sphere in
$\mathbb{R}^{3}.$ | 2310.07717v1 |
1994-10-06 | Damped Lyman Alpha Systems vs. Cold + Hot Dark Matter | Damped Ly$\alpha$ systems provide possibly the most significant evidence for
early structure formation, and thus a stringent constraint on the Cold + Hot
Dark Matter (CHDM) cosmology. Using the numbers of halos in N-body simulations
to normalize Press-Schechter (PS) estimates of the number densities of
protogalaxies as... | 9410022v1 |
1995-12-05 | Small Scale Structure and High Redshift HI | Cosmological simulations with gas dynamics suggest that the Lyman-alpha
forest is produced mainly by "small scale structure" --- filaments and sheets
that are the high redshift analog of today's galaxy superclusters. There is no
sharp distinction between Lyman-alpha clouds and "Gunn-Peterson" absorption
produced by the... | 9512016v1 |
1996-04-03 | APM z>4 QSO Survey: Spectra and Intervening Absorption Systems | The APM multicolor survey for bright z > 4 objects, covering 2500 deg^2 of
sky to m(R)~19, resulted in the discovery of thirty-one quasars with z > 4.
High signal-to-noise optical spectrophotometry at 5A resolution has been
obtained for the twenty-eight quasars easily accessible from the northern
hemisphere. These spec... | 9604021v1 |
1996-06-13 | Damping of Cosmic Magnetic Fields | We examine the evolution of magnetic fields in an expanding fluid composed of
matter and radiation with particular interest in the evolution of cosmic
magnetic fields. We derive the propagation velocities and damping rates for
relativistic and non-relativistic fast and slow magnetosonic, and Alfv\'en
waves in the prese... | 9606080v2 |
1997-01-09 | Molecular Hydrogen Absorption in the z= 1.97 Damped Lyman alpha Absorption system toward QSO 0013-004 | We present a new ultra-violet spectrum of the QSO 0013-004 with 0.9 \AA
resolution obtained with the MMT Blue spectrograph. The \upsilon = 0 - 0, 1 -
0, 2 - 0 and 3 - 0 Lyman bands of H_2 associated with the z = 1.9731 damped Ly
alpah absorption line system have been detected. The H_2 column density is
N(H_2) = 6.9 (\p... | 9701041v1 |
1997-02-06 | Abundance Patterns of Heavy Elements in Damped Lyman-Alpha Galaxies | We present a quantitative analysis of the abundances of heavy elements in
damped Ly-alpha galaxies in the sample of Lu et al. (1996). In particular, we
compare the observed gas-phase abundances with those expected when the
intrinsic (i.e., nucleosynthetic) pattern is the same as that in either the Sun
or in Galactic ha... | 9702066v2 |
1997-07-15 | Linear Response, Dynamical Friction and the Fluctuation-Dissipation Theorem in Stellar Dynamics | We apply linear response theory to a general, inhomogeneous, stationary
stellar system, with particular emphasis on dissipative processes analogous to
Landau damping. Assuming only that the response is causal, we show that the
irreversible work done by an external perturber is described by the
anti-Hermitian part of a ... | 9707161v1 |
1997-08-04 | Violent Relaxation, Phase Mixing, and Gravitational Landau Damping | This paper proposes a geometric interpretation of flows generated by the
collisionless Boltzmann equation (CBE), focusing on the coarse-grained approach
towards equilibrium. The CBE is a noncanonical Hamiltonian system with the
distribution function f the fundamental dynamical variable, the mean field
energy H[f] playi... | 9708026v1 |
1998-11-23 | The Physical Nature of the Lyman Limit Systems | We analyze Keck HIRES observations of a Lyman limit system at z=2.652 toward
Q2231-00. These observations afford the most comprehensive study of the
physical properties of a LL system to date. By comparing the ionic column
densities for Fe^+, Fe^{++}, Si^+, and Si^{3+} against calculations derived
from the CLOUDY softw... | 9811357v1 |
1998-12-03 | Gravity-Modes in ZZ Ceti Stars III. Eigenvalues and Eigenfuctions | We report on numerical calculations of nonadiabatic eigenvalues and
eigenfunctions for g-modes in ZZ Ceti variables. The spectrum of overstable
$l=1$ modes delineates the instability strip. Its blue edge occurs where
$\omega \tau_c \approx 1$ for the $n=1$ mode. Here $\omega$ is radian frequency
and $\tau_c$ is about f... | 9812085v1 |
1999-01-19 | Collisionless Dissipative Nonlinear Alfven Waves: Nonlinear Steepening, Compressible Turbulence, and Particle Trapping | The magnetic energy of nonlinear Alfven waves in compressible plasmas may be
ponderomotively coupled only to ion-acoustic quasi-modes which modulate the
wave phase velocity and cause wave-front steepening. In the collisionless
plasma with $\beta\not=0$, the dynamics of nonlinear Alfven wave is also
affected by the reso... | 9901257v1 |
2000-06-06 | A Model of Metallicity Evolution in the Early Universe | We apply the phenomenological model used to explain the abundances of Fe and
r-process elements in very metal-poor stars in the Galaxy to [Fe/H] of damped
Ly alpha systems. It is assumed that the first stars formed after the Big Bang
were very massive and promptly enriched the interstellar medium to [Fe/H] ~ -3,
at whi... | 0006082v2 |
2000-09-27 | Lensing properties of 7 damped Lyman-alpha absorbing galaxy-QSO pairs | Le Brun et al. (1997) presented the first identifications of the galaxies
giving rise to 7 intermediate redshift damped Ly-alpha (DLA) absorption
systems. Here, we study the gravitational lensing properties of these
foreground galaxies based on their observed optical appearance and on the
absence of any secondary lense... | 0009433v1 |
2000-11-14 | Sharp HI edges at high z: the gas distribution from Damped Lyman-alpha to Lyman-limit absorption systems | We derive the distribution of neutral and ionized gas in high redshift clouds
which are optically thick to hydrogen ionizing radiation, using published data
on Lyman-limit and Damped Lyman-alpha absorption systems in the redshift range
1.75 < z < 3.25. We assume that the distribution of the hydrogen total (HI+HII)
colu... | 0011268v1 |
2000-11-29 | Implications of 21cm observations for damped Ly-$α$ systems | We present Giant Metrewave Radio Telescope HI 21cm absorption observations,
of candidate and confirmed damped Lyman-$\alpha$ systems (DLAS). The derived
spin temperatures (T_s) are in all cases $\sim 1000$ K or higher. We have also
collated from the literature a list of DLAS for which 21cm observations exist,
and discu... | 0011540v1 |
2001-01-18 | A Comprehensive Statistical Analysis of the Gas Distribution in Lyman-limit and Damped Lyman-alpha Absorption Systems | In this paper we show how to use data on Lyman-limit and Damped Lyman-alpha
absorption systems to derive the hydrogen ionization fractions and the
distribution of the face-on total gas column density. We consider axially
symmetric, randomly oriented absorbers, ionized by an external background
radiation field in order ... | 0101335v1 |
2001-04-29 | The First Detection of Co in a Damped Lyman Alpha System | The study of elemental abundances in Damped Lyman Alpha systems (DLAs) at
high redshift represents one of our best opportunities to probe galaxy
formation and chemical evolution at early times. By coupling measurements made
in high z DLAs with our knowledge of abundances determined locally and with
nucleosynthetic mode... | 0104466v1 |
2001-06-22 | Self-Absorption of Ionizing Radiation and Extended Lyman Alpha Emission in High- Redshift QSOs | We calculate the neutral hydrogen column density of self-absorption in QSOs
predicted in a model where the QSOs are located in the same halos that contain
the gas in damped Lya absorption systems. The model is parameterized by the
probability P_0 that any halo has an active QSO. We assume that the QSOs ionize
the gas, ... | 0106424v2 |
2001-06-22 | Compressible MHD Turbulence in Interstellar Plasmas | Radio-wave scintillation observations reveal a nearly Kolmogorov spectrum of
density fluctuations in the ionized interstellar medium. Although this density
spectrum is suggestive of turbulence, no theory relevant to its interpretation
exists. We calculate the density spectrum in turbulent magnetized plasmas by
extendin... | 0106425v1 |
2001-11-20 | Collisional Cascades in Planetesimal Disks I. Stellar Flybys | We use a new multiannulus planetesimal accretion code to investigate the
evolution of a planetesimal disk following a moderately close encounter with a
passing star. The calculations include fragmentation, gas and
Poynting-Robertson drag, and velocity evolution from dynamical friction and
viscous stirring. We assume th... | 0111384v1 |
2002-02-11 | The Contribution of HI-rich Galaxies to the Damped Lyman-alpha Absorber Population at z=0 | We present a study of the expected properties of the low redshift damped
Lyman-alpha absorber population determined from a sample of HI-selected
galaxies in the local universe. Because of a tight correlation between the HI
mass and HI cross-section, which we demonstrate spans all galaxy types, we can
use our HI-selecte... | 0202216v2 |
2002-03-18 | Monte Carlo Simulation of Lyman Alpha Scattering and Application to Damped Lyman Alpha Systems | A Monte Carlo code to solve the transfer of Lyman alpha (Lya) photons is
developed, which can predict the Lya image and two-dimensional Lya spectra of a
hydrogen cloud with any given geometry, Lya emissivity, neutral hydrogen
density distribution, and bulk velocity field. We apply the code to several
simple cases of a ... | 0203287v2 |
2002-04-09 | The Non-Damped Nature of Twelve Low-Redshift Damped Lyman Alpha Candidate Systems | Hubble Space Telescope (HST) UV spectroscopy of 12 candidate low-redshift
damped Lyman alpha (DLA) systems in 11 QSOs (z=0.103 in Q0054+144, z=0.969 and
z=0.987 in Q0302-223, z=0.478 in Q0454-220, z=1.476 in Q1047+550, z=1.070 in
Q1206+459, z=1.228 in Q1247+267, z=0.399 in Q1318+290B, z=0.519 in Q1329+412,
z=0.276 in Q... | 0204155v1 |
2002-05-17 | High matter density peaks from UVES observations of QSO pairs: correlation properties and chemical abundances | We study the transverse clustering properties of high matter density peaks as
traced by high column density absorption systems (either Lyman limit systems
characterized by N(HI)> 2 x 10^{17} cm^{-2} or CIV systems with W_{r}> 0.5 A)
at redshifts between 2 and 3 with UVES spectra of two QSO pairs (UM680/UM681 at
56 arcs... | 0205299v1 |
2002-08-28 | Complex rotation with internal dissipation. Applications to cosmic-dust alignment and to wobbling comets and asteroids | Neutron stars, asteroids, comets, cosmic-dust granules, spacecraft, as well
as whatever other freely spinning body dissipate energy when they rotate about
any axis different from principal. We discuss the internal-dissipation-caused
relaxation of a freely precessing rotator towards its minimal-energy mode (mode
that co... | 0208489v1 |
2003-06-16 | Damping of Tensor Modes in Cosmology | An analytic formula is given for the traceless transverse part of the
anisotropic stress tensor due to free streaming neutrinos, and used to derive
an integro-differential equation for the propagation of cosmological
gravitational waves. The solution shows that anisotropic stress reduces the
squared amplitude by 35.6 %... | 0306304v2 |
2003-12-30 | Nonlinear Pulsations in Differentially Rotating Neutron Stars: Mass-Shedding-Induced Damping and Splitting of the Fundamental Mode | We study small-amplitude, nonlinear pulsations of uniformly and
differentially rotating neutron stars employing a two-dimensional evolution
code for general-relativistic hydrodynamics. Using Fourier transforms at
several points inside the star, both the eigenfrequencies and two-dimensional
eigenfunctions of pulsations ... | 0312648v2 |
2004-01-16 | Simulating stochastically excited oscillations. The mode lifetime of xi Hya | The discovery of solar-like oscillations in the giant star xy Hya (G7III) was
reported by Frandsen et al. (2002). Their frequency analysis was very limited
due to alias problems in the data set (caused by single-site observations). The
extent to which the aliasing affected their analysis was unclear due to the
unknown ... | 0401331v1 |
2004-10-13 | On the Importance of Local Sources of Radiation in Cosmological Absorption Systems | An upper limit to the importance of local sources of radiation compared to
the cosmic background in cosmological absorption systems is derived, as a
simple consequence of the conservation of surface brightness. The limit depends
only on the rate of incidence of the absorbers and the mean free path of the
radiation. It ... | 0410315v1 |
2005-04-04 | Relativistic r-modes and Shear viscosity: regularizing the continuous spectrum | Within a fully relativistic framework, we derive and solve numerically the
perturbation equations of relativistic stars, including the stresses produced
by a non-vanishing shear viscosity in the stress-energy tensor. With this
approach, the real and imaginary parts of the frequency of the modes are
consistently obtaine... | 0504062v1 |
2005-04-29 | Evidence for a magnitude-dependent bias in the Hamburg/ESO Survey for Damped Lyman-alpha Systems | We present preliminary results from the Hamburg/ESO survey for Damped
Ly-alpha (hereafter, DLA) Systems. This survey is characterized by (i) the good
knowledge of the biases affecting the parent QSO survey, (ii) the brightness
and (iii) the relatively wide magnitude distribution of the background QSOs.
Therefore, it is... | 0504657v1 |
2005-10-12 | Ly-alpha Radiative Transfer in Cosmological Simulations and Application to a z~8 Emitter | We develop a Ly-alpha radiative transfer (RT) Monte Carlo code for
cosmological simulations.High resolution,along with appropriately treated
cooling can result in simulated environments with very high optical
depths.Thus,solving the Ly-alpha RT problem in cosmological simulations can
take an unrealistically long time.F... | 0510347v2 |
2005-12-05 | Kinematics and star formation activity in the z=2.03954 damped Lyman-alpha system towards PKS 0458-020 | We present UVES observations of the log N(HI)= 21.7 damped Lyman-alpha system
at z=2.03954 towards the quasar PKS 0458-020. HI Lyman-alpha emission is
detected in the center of the damped Lyman-alpha absorption trough.
Metallicities are derived for MgII, SiII, PII, CrII, MnII, FeII and ZnII and
are found to be -1.21\pm... | 0512118v1 |
2006-02-14 | On the magnetic structure and wind parameter profiles of Alfven wave driven winds in late-type supergiant stars | Cool stars at giant and supergiant evolutionary phases present low velocity
and high density winds, responsible for the observed high mass-loss rates.
Although presenting high luminosities, radiation pressure on dust particles is
not sufficient to explain the wind acceleration process. Among the possible
solutions to t... | 0602305v1 |
2006-03-17 | Electron impact excitation of Helium-like ions up to n=4 levels including radiation damping | Helium-like ions provide the most important X-ray spectral diagnostics in
high temperature fusion and astrophysical plasmas. We previously presented
computed collision strengths for O~VII including relativistic fine structure,
levels up to the $n=4$ complex and radiation damping of autoionizing
resonances. We have exte... | 0603482v1 |
2006-07-25 | Metal-rich Damped/sub-Damped Lyman-alpha Quasar Absorbers at z<1 | Damped Lyman-alpha absorbers (DLAs), seen in absorption against a background
quasar, provide the most detailed probes available of element abundances in the
Universe over > 90 % of its age. DLAs can be used to observationally measure
the global mean metallicity in the Universe and its evolution with time.
Paradoxically... | 0607561v1 |
1998-06-21 | Collective intersubband transitions in quantum wells: a comparative density-functional study | We use time-dependent (current) density functional theory to study collective
transitions between the two lowest subbands in GaAs/AlGaAs quantum wells. We
focus on two systems where experimental results are available: a wide single
and a narrow asymmetric double well. The aim is to calculate frequency and
linewidth of ... | 9806252v1 |
1998-11-27 | Renormalization group analysis of the quantum non-linear sigma model with a damping term | We investigate the behavior of the zero-temperature quantum non-linear sigma
model in d dimensions in the presence of a damping term of the form f(w)~
|w|^alpha, with 1 \le alpha <2. We find two fixed points: a spin-wave fixed
point FP1 showing a dynamic scaling exponent z=1 and a dissipative fixed point
FP2 with z>1. ... | 9811392v2 |
1999-12-14 | Spinwave damping in the two-dimensional ferromagnetic XY model | The effect of damping of spinwaves in a two-dimensional classical
ferromagnetic XY model is considered. The damping rate $\Gamma_{q}$ is
calculated using the leading diagrams due to the quartic-order deviations from
the harmonic spin Hamiltonian. The resulting four-dimensional integrals are
evaluated by extending the t... | 9912241v1 |
2002-01-25 | Time-dependent current density functional theory for the linear response of weakly disordered systems | This paper develops a quantitatively accurate first-principles description
for the frequency and the linewidth of collective electronic excitations in
inhomogeneous weakly disordered systems. A finite linewidth in general has
intrinsic and extrinsic sources. At low temperatures and outside the region
where electron-pho... | 0201483v1 |
2003-06-10 | Oscillations of Bose-Einstein condensates with vortex lattices. II. Finite temperatures | We derive the finite temperature oscillation modes of a harmonically confined
Bose-Einstein condensed gas undergoing rigid body rotation supported by a
vortex lattice in the condensate. The hydrodynamic modes separate into two
classes corresponding to in-phase (center-of-mass) and counter-phase (relative)
oscillations ... | 0306245v2 |
2004-05-14 | Thermoelastic relaxation in elastic structures with applications to thin plates | A new result enables direct calculation of thermoelastic damping in vibrating
elastic solids. The mechanism for energy loss is thermal diffusion caused by
inhomogeneous deformation, flexure in thin plates. The general result is
combined with the Kirchhoff assumption to obtain a new equation for the
flexural vibration o... | 0405323v2 |
2005-04-21 | Ultrafast dynamics of coherent optical phonons and nonequilibrium electrons in transition metals | The femtosecond optical pump-probe technique was used to study dynamics of
photoexcited electrons and coherent optical phonons in transition metals Zn and
Cd as a function of temperature and excitation level. The optical response in
time domain is well fitted by linear combination of a damped harmonic
oscillation becau... | 0504540v1 |
2005-10-10 | Quantum master equation descriptions of a nanomechanical resonator coupled to a single-electron transistor | We analyse the quantum dynamics of a nanomechanical resonator coupled to a
normal-state single-electron transistor (SET). Starting from a microscopic
description of the system, we derive a master equation for the SET island
charge and resonator which is valid in the limit of weak electro-mechanical
coupling. Using this... | 0510236v1 |
2005-10-16 | Magnetic vortex dynamics in a 2D easy plane ferromagnet | In this thesis, we consider the dynamics of vortices in the easy plane
insulating ferromagnet in two dimensions. In addition to the quasiparticle
excitations, here spin waves or magnons, this magnetic system admits a family
of vortex solutions carrying two topological invariants, the winding number or
vorticity, and th... | 0510414v1 |
2006-05-19 | Enhancement of noncontact friction between closely spaced bodies by two-dimensional systems | . We consider the effect of an external bias voltage and the spatial
variation of the surface potential, on the damping of cantilever vibrations.
The electrostatic friction is due to energy losses in the sample created by the
electromagnetic field from the oscillating charges induced on the surface of
the tip by the bi... | 0605480v1 |
2006-09-12 | Slowing down Josephson vortex lattice in Bi_2Sr_2CaCu_2O_{8+d} with pancake vortices | We study theoretically and experimentally influence of pancake vortices on
motion of the Josephson vortex lattice in layered high-temperature
superconductors. Mobility of the Josephson vortices in layered superconductors
is strongly suppressed by small amount of pancake-vortex stacks. Moving
Josephson vortex lattice fo... | 0609262v2 |
2006-02-01 | Radiation Damping in Einstein-Aether Theory | This work concerns the loss of energy of a material system due to
gravitational radiation in Einstein-aether theory-an alternative theory of
gravity in which the metric couples to a dynamical, timelike, unit-norm vector
field. Derived to lowest post-Newtonian order are waveforms for the metric and
vector fields far fro... | 0602004v5 |
1998-02-20 | Real-time Relaxation and Kinetics in Hot Scalar QED: Landau Damping | The real time evolution of field condensates with soft length scales
k^{-1}>(eT)^{-1} is solved in hot scalar electrodynamics, with a view towards
understanding relaxational phenomena in the QGP and the electroweak plasma. We
find that transverse gauge invariant non-equilibrium expectation values of
fields relax via {\... | 9802370v2 |
2003-03-04 | Asymptotic quasinormal modes of Reissner-Nordström and Kerr black holes | According to a recent proposal, the so-called Barbero-Immirzi parameter of
Loop Quantum Gravity can be fixed, using Bohr's correspondence principle, from
a knowledge of highly-damped black hole oscillation frequencies. Such
frequencies are rather difficult to compute, even for Schwarzschild black
holes. However, it is ... | 0303029v3 |
2005-01-28 | Summation of divergent series and Borel summability for strongly dissipative equations with periodic or quasi-periodic forcing terms | We consider a class of second order ordinary differential equations
describing one-dimensional systems with a quasi-periodic analytic forcing term
and in the presence of damping. As a physical application one can think of a
resistor-inductor-varactor circuit with a periodic (or quasi-periodic) forcing
function, even if... | 0501500v1 |
1997-11-17 | Fusion and Binary-Decay Mechanisms in the $^{35}$Cl+$^{24}$Mg System at E/A $\approx$ 8 MeV/Nucleon | Compound-nucleus fusion and binary-reaction mechanisms have been investigated
for the $^{35}$Cl+$^{24}$Mg system at an incident beam energy of E$_{Lab}$= 282
MeV. Charge distributions, inclusive energy spectra, and angular distributions
have been obtained for the evaporation residues and the binary fragments.
Angle-int... | 9711005v1 |
1996-12-31 | Fluid Models for Kinetic Effects on Coherent Nonlinear Alfven Waves. II. Numerical Solutions | The influence of various kinetic effects (e.g. Landau damping, diffusive and
collisional dissipation, and finite Larmor radius terms) on the nonlinear
evolution of finite amplitude Alfvenic wave trains in a finite-beta environment
is systematically investigated using a novel, kinetic nonlinear Schrodinger
(KNLS) equati... | 9612018v1 |
2000-09-06 | Design, fabrication and measurement of the first rounded damped detuned accelerator structure (RDDS1) | As a joint effort in the JLC/NLC research program, we have developed a new
type of damped detuned accelerator structure with optimized round-shaped
cavities (RDDS). This paper discusses some important R&D aspects of the first
structure in this series (RDDS1). The design aspects covered are the cell
design with sub-MHz ... | 0009025v1 |
2001-07-19 | Dipole Wakefield Suppression In High Phase Advance Detuned Linear Accelerators For The JLC/NLC Designed To Minimise Electrical Breakdown And Cumulative BBU | Recent experiments at SLAC [1,2] and CERN [3] have revealed evidence of
significant deformation in the form of "pitting" of the cells of the 1.8m
series of structures DDS/RDDS (Damped Detuned Structure/Rounded Damped Detuned
Structure). This pitting occurs in the high group velocity (vg /c = 0.012) end
of the accelerat... | 0107049v1 |
2000-12-10 | Chaotic atomic population oscillations between two coupled Bose-Einstein condensates with time-dependent asymmetric trap potential | We have investigated the chaotic atomic population oscillations between two
coupled Bose-Einstein condensates (BEC) with time-dependent asymmetric trap
potential. In the perturbative regime, the population oscillations can be
described by the Duffing equation, and the chaotic oscillations near the
separatrix solution a... | 0012043v1 |
2003-01-23 | Revivals and entanglement from initially entangled mixed states of a damped Jaynes-Cummings model | An exact density matrix of a phase-damped Jaynes - Cummings model (JCM) with
entangled Bell-like initial states formed from a model two-state atom and sets
of adjacent photon number states of a single mode radiation field is presented.
The entanglement of the initial states and the subsequent time evolution is
assured ... | 0301126v1 |
2003-03-18 | A Method for Modeling Decoherence on a Quantum Information Processor | We develop and implement a method for modeling decoherence processes on an
N-dimensional quantum system that requires only an $N^2$-dimensional quantum
environment and random classical fields. This model offers the advantage that
it may be implemented on small quantum information processors in order to
explore the inte... | 0303115v1 |
2005-11-25 | The electrodynamic 2-body problem and the origin of quantum mechanics | We numerically solve the functional differential equations (FDE's) of
2-particle electrodynamics, using the full electrodynamic force obtained from
the retarded Lienard-Wiechert potentials and the Lorentz force law. In
contrast, the usual formulation uses only the Coulomb force (scalar potential),
reducing the electrod... | 0511235v1 |
2007-05-11 | Ground-state cooling of a micromechanical oscillator: generalized framework for cold damping and cavity-assisted cooling schemes | We provide a general framework to describe cooling of a micromechanical
oscillator to its quantum ground state by means of radiation-pressure coupling
with a driven optical cavity. We apply it to two experimentally realized
schemes, back-action cooling via a detuned cavity and cold-damping
quantum-feedback cooling, and... | 0705.1728v6 |
2007-11-08 | Solving non-linear equations of longitudinal and transverse electron waves in collisionless Maxwellian plasma | We have considered an expansion of solutions of the non-linear equations for
both longitudinal and transverse waves in collisionless Maxwellian plasma in
series of non-damping overtones of the field E(x,t) and electron velocity
distribution function f=f(0) +f(1) where f(0) is background Maxwellian electron
distribution... | 0711.1321v8 |
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