publicationDate stringlengths 1 2.79k | title stringlengths 1 36.5k ⌀ | abstract stringlengths 1 37.3k ⌀ | id stringlengths 9 47 |
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2002-07-09 | Optical phase-space reconstruction of mirror position at the attometer level | We describe an experiment in which the quadratures of the position of an
harmonically-bound mirror are observed at the attometer level. We have studied
the Brownian motion of the mirror, both in the free regime and in the
cold-damped regime when an external viscous force is applied by radiation
pressure. We have also s... | 0207049v2 |
2002-07-10 | Error prevention scheme with two pairs of qubits | A scheme is presented for protecting one-qubit quantum information against
decoherence due to a general environment and local exchange interactions. The
scheme operates essentially by distributing information over two pairs of
qubits and through error prevention procedures. In the scheme, quantum
information is encoded... | 0207063v1 |
2002-08-05 | Path Integrals and Their Application to Dissipative Quantum Systems | Introduction
Path Integrals
- Introduction
- Propagator
- Free Particle
- Path Integral Representation of Quantum Mechanics
- Particle on a Ring
- Particle in a Box
- Driven Harmonic Oscillator
- Semiclassical Approximation
- Imaginary Time Path Integral
Dissipative Systems
- Introduction
- En... | 0208026v1 |
2002-11-25 | Robust Entanglement in Atomic Systems via Lambda-Type Processes | It is shown that the system of two three-level atoms in $\Lambda$
configuration in a cavity can evolve to a long-lived maximum entangled state if
the Stokes photons vanish from the cavity by means of either leakage or
damping. The difference in evolution picture corresponding to the general model
and effective model wi... | 0211157v1 |
2003-04-29 | Stability of stationary solutions of the Schrodinger-Langevin equation | The stability properties of a class of dissipative quantum mechanical systems
are investigated. The nonlinear stability and asymptotic stability of
stationary states (with zero and nonzero dissipation respectively) is
investigated by Liapunov's direct method. The results are demonstrated by
numerical calculations on th... | 0304190v3 |
2003-07-09 | Teleportation in a noisy environment: a quantum trajectories approach | We study the fidelity of quantum teleportation for the situation in which
quantum logic gates are used to provide the long distance entanglement required
in the protocol, and where the effect of a noisy environment is modeled by
means of a generalized amplitude damping channel. Our results demonstrate the
effectiveness... | 0307065v1 |
2003-07-30 | Maser and Laser Action with One Atom | We present a theory which can explain the micromaser as well as its optical
counterpart, the microlaser, for appropriate values of dissipative parameters.
We show that, in both the the cases, the cavity radiation fields can have
sub-Poissonian photon statistics. We further analyse if it is possible to
attain a Fock sta... | 0307226v1 |
2003-08-25 | Single Atom Cooling by Superfluid Immersion: A Non-Destructive Method for Qubits | We present a scheme to cool the motional state of neutral atoms confined in
sites of an optical lattice by immersing the system in a superfluid. The motion
of the atoms is damped by the generation of excitations in the superfluid, and
under appropriate conditions the internal state of the atom remains unchanged.
This s... | 0308129v1 |
2003-11-08 | Cavity-induced damping and level shifts in a wide aperture spherical resonator | We calculate explicitly the space dependence of the radiative relaxation
rates and associated level shifts for a dipole placed in the vicinity of the
center of a spherical cavity with a large numerical aperture and a relatively
low finesse. In particular, we give simple and useful analytic formulas for
these quantities... | 0311047v2 |
2003-12-17 | Quantum dynamics in single spin measurement | We study the quantum dynamics of a model for the single-spin measurement in
magnetic-resonance force microscopy. We consider an oscillating driven
cantilever coupled with the magnetic moment of the sample. Then, the cantilever
is damped through an external bath and its readout is provided by a radiation
field. Conditio... | 0312147v2 |
2004-01-28 | The Semiclassical Regime of the Chaotic Quantum-Classical Transition | An analysis of the semiclassical regime of the quantum-classical transition
is given for open, bounded, one dimensional chaotic dynamical systems.
Environmental fluctuations -- characteristic of all realistic dynamical systems
-- suppress the development of fine structure in classical phase space and damp
nonlocal cont... | 0401174v4 |
2004-03-02 | Completely-Positive Non-Markovian Decoherence | We propose an effective Hamiltonian approach to investigate decoherence of a
quantum system in a non-Markovian reservoir, naturally imposing the complete
positivity on the reduced dynamics of the system. The formalism is based on the
notion of an effective reservoir, i.e., certain collective degrees of freedom
in the r... | 0403018v1 |
2004-03-23 | Optimal probabilistic cloning and purification of quantum states | We investigate the probabilistic cloning and purification of quantum states.
The performance of these probabilistic operations is quantified by the average
fidelity between the ideal and actual output states. We provide a simple
formula for the maximal achievable average fidelity and we explictly show how
to construct ... | 0403165v1 |
2004-05-19 | Information-capacity description of spin-chain correlations | Information capacities achievable in the multi-parallel-use scenarios are
employed to characterize the quantum correlations in unmodulated spin chains.
By studying the qubit amplitude damping channel, we calculate the quantum
capacity $Q$, the entanglement assisted capacity $C_E$, and the classical
capacity $C_1$ of a ... | 0405110v3 |
2004-06-11 | Optimal estimation of one parameter quantum channels | We explore the task of optimal quantum channel identification, and in
particular the estimation of a general one parameter quantum process. We derive
new characterizations of optimality and apply the results to several examples
including the qubit depolarizing channel and the harmonic oscillator damping
channel. We als... | 0406070v3 |
2004-12-02 | Transient dynamics of linear quantum amplifiers | The transient dynamics of a quantum linear amplifier during the transition
from damping to amplification regime is studied. The master equation for the
quantized mode of the field is solved, and the solution is used to describe the
statistics of the output field. The conditions under which a nonclassical input
field ma... | 0412018v2 |
2005-02-13 | A minimal coupling method for investigating one dimensional dissipative quantum systems | Quantum mechanics of a general one dimensional dissipative system
investigated by it's coupling to a Klein-Gordon field as the environment using
a minimal coupling method. Heisenberg equation for such a dissipative system
containing a dissipative term proportional to velocity obtained. As an example,
quantum dynamics o... | 0502076v2 |
2005-02-22 | Minimal coupling method and the dissipative scalar field theory | Quantum field theory of a damped vibrating string as the simplest dissipative
scalar field investigated by its coupling with an infinit number of
Klein-Gordon fields as the environment by introducing a minimal coupling
method. Heisenberg equation containing a dissipative term proportional to
velocity obtained for a spe... | 0502134v2 |
2005-04-29 | Stationary state entanglement and total correlation of two qubits or qutrits | We investigate the mutual information and entanglement of stationary state of
two locally driven qubits under the influence of collective dephasing. It is
shown that both the mutual information and the entanglement of two qubits in
the stationary state exhibit damped oscillation with the scaled action time
$\gamma{T}$ ... | 0504228v1 |
2005-05-22 | Fast SWAP gate by adiabatic passage | We present a process for the construction of a SWAP gate which does not
require a composition of elementary gates from a universal set. We propose to
employ direct techniques adapted to the preparation of this specific gate. The
mechanism, based on adiabatic passage, constitutes a decoherence-free method in
the sense t... | 0505163v2 |
2005-08-15 | Quantum electromdynamics in a linear absorbing dielectric medium | The eletromagnetic field in a linear absorptive dielectric medium, is
quantized in the framework of the damped polarization model. A Hamiltonian
containing a reservoir with continuous degrees of freedom, is proposed. The
reservoir minimally interacts with the dielectric polarization and the
electromagnetic field. The L... | 0508107v1 |
2005-08-18 | The harmonic oscillator with dissipation within the theory of open quantum systems | Time evolution of the expectation values of various dynamical operators of
the harmonic oscillator with dissipation is analitically obtained within the
framework of the Lindblad theory for open quantum systems. We deduce the
density matrix of the damped harmonic oscillator from the solution of the
Fokker-Planck equatio... | 0508140v1 |
2005-09-02 | A dynamical model for quantum memory channels | A dynamical model for quantum channel is introduced which allows one to pass
continuously from the memoryless case to the case in which memory effects are
present. The quantum and classical communication rates of the model are defined
and explicit expression are provided in some limiting case. In this context we
introd... | 0509016v2 |
2005-09-19 | Feedback cooling of a single trapped ion | Based on a real-time measurement of the motion of a single ion in a Paul
trap, we demonstrate its electro-mechanical cooling below the Doppler limit by
homodyne feedback control (cold damping). The feedback cooling results are well
described by a model based on a quantum mechanical Master Equation. | 0509125v1 |
2005-09-27 | CNOT gate by adiabatic passage with an optical cavity | We propose a scheme for the construction of a CNOT gate by adiabatic passage
in an optical cavity. In opposition to a previously proposed method, the
technique is not based on fractional adiabatic passage, which requires the
control of the ratio of two pulse amplitudes. Moreover, the technique
constitutes a decoherence... | 0509187v1 |
2005-12-12 | Decoherence-free manipulation of photonic memories for quantum computation | We present a protocol to construct an arbitrary quantum circuit. The quantum
bits (qubits) are encoded in polarisation states of single photons. They are
stored in spatially separated dense media deposed in an optical cavity.
Specific sequences of pulses address individually the storage media to encode
the qubits and t... | 0512084v1 |
2006-01-23 | Detuned Electromagnetically Induced Transparency in an $N$-type Atom | The electromagnetically induced transparency (EIT) in an $N$ configuration is
studied under both resonant and off-resonant conditions. In a certain
off-resonant condition the dark state of the four level system, which is almost
the same as the resonant dark state in $\Lambda$ configuration, is rebuilt. The
actual syste... | 0601153v2 |
2006-04-28 | Purity of states in the theory of open quantum systems | The condition of purity of states for a damped harmonic oscillator is
considered in the framework of Lindblad theory for open quantum systems. For a
special choice of the environment coefficients, the correlated coherent states
are shown to be the only states which remain pure all the time during the
evolution of the c... | 0604212v1 |
2006-05-23 | Continuous observation of a squeezed coherent state | The main aim of the paper is to present the analytical solution of the
Belavkin quantum filtering equation for damped harmonic oscillator being
initially in the squeezed coherent state for diffusion observation with complex
white noise. The comparison of the a priori and a posteriori mean value of the
optical quadratur... | 0605200v2 |
2006-06-27 | Quantum decoherence of the damped harmonic oscillator | In the framework of the Lindblad theory for open quantum systems, we
determine the degree of quantum decoherence of a harmonic oscillator
interacting with a thermal bath. It is found that the system manifests a
quantum decoherence which is more and more significant in time. We also
calculate the decoherence time and sh... | 0606222v1 |
2006-08-16 | Characterization of unwanted noise in realistic cavities | The problem of the description of absorption and scattering losses in high-Q
cavities is studied. The considerations are based on quantum noise theories,
hence the unwanted noise associated with scattering and absorption is taken
into account by introduction of additional damping and noise terms in the
quantum Langevin... | 0608126v1 |
2006-10-27 | Quantum-limited force measurement with an optomechanical device | We study the detection of weak coherent forces by means of an optomechanical
device formed by a highly reflecting isolated mirror shined by an intense and
highly monochromatic laser field. Radiation pressure excites a vibrational mode
of the mirror, inducing sidebands of the incident field, which are then
measured by h... | 0610236v1 |
2006-11-08 | Quantum superchemistry in an output coupler of coherent matter waves | We investigate the quantum superchemistry or Bose-enhanced atom-molecule
conversions in a coherent output coupler of matter waves, as a simple
generalization of the two-color photo-association. The stimulated effects of
molecular output step and atomic revivals are exhibited by steering the rf
output couplings. The qua... | 0611088v1 |
2007-02-01 | Field quantization in inhomogeneous anisotropic dielectrics with spatio-temporal dispersion | A quantum damped-polariton model is constructed for an inhomogeneous
anisotropic linear dielectric with arbitrary dispersion in space and time. The
model Hamiltonian is completely diagonalized by determining the creation and
annihilation operators for the fundamental polariton modes as specific linear
combinations of t... | 0702010v2 |
2007-02-15 | Quantum Mechanics with Complex Time : A Comment to the Paper by Rajeev | In (quant-ph/0701141) Rajeev studied quantization of the damped simple
harmonic oscillator and introduced a complex-valued Hamiltonian (which is
normal). In this note we point out that the quantization is interpreted as a
quantum mechanics with {\bf complex time}. We also present a problem on
quantization of classical ... | 0702148v1 |
2007-03-18 | Lindblad master equation for the damped harmonic oscillator with deformed dissipation | In the framework of the Lindblad theory for open quantum systems, a master
equation for the quantum harmonic oscillator interacting with a dissipative
environment, in particular with a thermal bath, is derived for the case when
the interaction is based on deformed algebra. The equations of motion for
observables strong... | 0703165v1 |
2007-04-06 | Bremsstrahlung Radiation At a Vacuum Bubble Wall | When charged particles collide with a vacuum bubble, they can radiate strong
electromagnetic waves due to rapid deceleration. Owing to the energy loss of
the particles by this bremsstrahlung radiation, there is a non-negligible
damping pressure acting on the bubble wall even when thermal equilibrium is
maintained. In t... | 0704.0837v1 |
2007-04-11 | Effects of atomic interactions on Quantum Accelerator Modes | We consider the influence of the inclusion of interatomic interactions on the
delta-kicked accelerator model. Our analysis concerns in particular quantum
accelerator modes, namely quantum ballistic transport near quantal resonances.
The atomic interaction is modelled by a Gross-Pitaevskii cubic nonlinearity,
and we add... | 0704.1382v1 |
2007-04-17 | Dissipation in graphene and nanotube resonators | Different damping mechanisms in graphene nanoresonators are studied: charges
in the substrate, ohmic losses in the substrate and the graphene sheet,
breaking and healing of surface bonds (Velcro effect), two level systems,
attachment losses, and thermoelastic losses. We find that, for realistic
structures and contrary ... | 0704.2225v3 |
2007-04-19 | Substrate temperature changes during MBE growth of GaMnAs | Remarkably big increase of the substrate temperature during the
low-temperature MBE growth of GaMnAs layers is observed by means of band gap
spectroscopy. It is explained and simulated in terms of changes in the
absorption/emission characteristics of the growing layer. Options for the
temperature variation damping are ... | 0704.2485v1 |
2007-04-29 | Effect of Decoherence on the Dynamics of Bose-Einstein Condensates in a Double-well Potential | We study the dynamics of a Bose-Einstein condensate in a double-well
potential in the mean-field approximation. Decoherence effects are considered
by analyzing the couplings of the condensate to environments. Two kinds of
coupling are taken into account. With the first kind of coupling dominated, the
decoherence can en... | 0704.3823v1 |
2007-05-08 | Theoretical Analysis of Subthreshold Oscillatory Behaviors in Nonlinear Autonomous Systems | We have developed a linearization method to investigate the subthreshold
oscillatory behaviors in nonlinear autonomous systems. By considering firstly
the neuronal system as an example, we show that this theoretical approach can
predict quantitatively the subthreshold oscillatory activities, including the
damping coeff... | 0705.1019v1 |
2007-05-08 | Supersymmetric methods in the traveling variable: inside neurons and at the brain scale | We apply the mathematical technique of factorization of differential
operators to two different problems. First we review our results related to the
supersymmetry of the Montroll kinks moving onto the microtubule walls as well
as mentioning the sine-Gordon model for the microtubule nonlinear excitations.
Second, we fin... | 0705.1134v1 |
2007-05-11 | Kerr quasinormal modes and Hod's time-temperature bound | We give an explicit expression for the frequencies of slowly damped
quasinormal modes of near-extreme Kerr black holes. It follows from this
expression that the near-extreme Kerr holes obey the Hod's bound: in the limit
of maximal rotation, $\lim \sup \omega_{IS}/T\leq \pi / \hbar$, where $\omega
_{IS}$ is the decay ra... | 0705.1725v1 |
2007-05-14 | X-ray emission from magnetic dissipation in the magnetar magnetosphere | Magnetic dissipation through decay of Alfven waves in the magnetar
magnetosphere is discussed. Transport of magnetic fields in the star leads to
dissipation of the magnetic energy through either direct internal heating or
transferring of the energy in waves that decay in the magnetar magnetosphere.
In the latter case, ... | 0705.1859v1 |
2007-05-14 | Effects of dissipation on a quantum critical point with disorder | We study the effects of dissipation on a disordered quantum phase transition
with O$(N)$ order parameter symmetry by applying a strong-disorder
renormalization group to the Landau-Ginzburg-Wilson field theory of the
problem. We find that Ohmic dissipation results in a non-perturbative
infinite-randomness critical point... | 0705.1865v3 |
2007-05-20 | Heat transfer in sound propagation and attenuation through gas-liquid polyhedral foams | A cell method is developed, which takes into account the bubble geometry of
polyhedral foams, and provides for the generalized Rayleigh-Plesset equation
that contains the non-local in time term corresponding to heat relaxation. The
Rayleigh-Plesset equation together with the equations of mass and momentum
balances for ... | 0705.2894v1 |
2007-05-28 | Ground state of the time-independent Gross-Pitaevskii equation | We present a suite of programs to determine the ground state of the
time-independent Gross-Pitaevskii equation, used in the simulation of
Bose-Einstein condensates. The calculation is based on the Optimal Damping
Algorithm, ensuring a fast convergence to the true ground state. Versions are
given for the one-, two-, and... | 0705.4024v2 |
2007-05-29 | Fresnel-transform's quantum correspondence and quantum optical ABCD Law | Corresponding to Fresnel transform there exists a unitary operator in quantum
optics theory, which could be named Fresnel operator (FO). We show that the
multiplication rule of FO naturally leads to the quantum optical ABCD law. The
canonical operator methods as mapping of ray-transfer ABCD matrix is explicitly
shown b... | 0705.4184v1 |
2007-06-07 | Lagrangians Galore | Searching for a Lagrangian may seem either a trivial endeavour or an
impossible task. In this paper we show that the Jacobi last multiplier
associated with the Lie symmetries admitted by simple models of classical
mechanics produces (too?) many Lagrangians in a simple way. We exemplify the
method by such a classic as t... | 0706.1008v1 |
2007-06-12 | Theory of the Pseudospin Resonance in Semiconductor Bilayers | The pseudospin degree of freedom in a semiconductor bilayer gives rise to a
collective mode analogous to the ferromagnetic resonance mode of a ferromagnet.
We present a theory of the dependence of the energy and the damping of this
mode on layer separation $d$. Based on these results, we discuss the
possibility of real... | 0706.1702v1 |
2007-06-19 | Evidence for Growth of Eccentricity and Mass Clearing in a Disc Interior to a Planet | We present computational results showing eccentricity growth in the inner
portions of a protoplanetary disc. We attribute this to the evolving surface
density of the disc. The planet creates a gap, which adjusts the balance
between the 3:1 (eccentricity exciting) and 2:1 (eccentricity damping)
resonances. The eccentric... | 0706.2801v1 |
2007-06-23 | Incoherent mid-infrared charge excitation and the high energy anomaly in the photoemission spectra of cuprates | On the basis of a semi-phenomenological model, it is argued that the high
energy anomaly observed in recent photoemission experiments on cuprates is
caused by interaction with an overdamped bosonic mode in the mid-infrared
region of the spectrum. Analysis of optical conductivity allows to connect this
excitation to the... | 0706.3449v1 |
2007-07-05 | Magnetic-order induced phonon splitting in MnO from far-infrared spectroscopy | Detailed far-infrared spectra of the optical phonons are reported for
antiferromagnetic MnO. Eigenfrequencies, phonon damping and effective plasma
frequencies are studied as a function of temperature. Special attention is paid
to the phonon splitting at the antiferromagnetic phase transition. The results
are compared t... | 0707.0820v2 |
2007-07-12 | Generalised Inverse-Cowling Approximation for Polar $w$-mode Oscillations of Neutron Stars | Adopting the Lindblom-Detweiler formalism for polar oscillations of neutron
stars, we study the $w$-mode oscillation and find that the Lagrangian change in
pressure, measured by the physical quantity $X$, is negligibly small. Based on
this observation, we develop the generalised inverse-Cowling approximation
(GICA) wit... | 0707.1727v1 |
2007-08-07 | Experimental Demonstration of Decoherence-Free One-Way Information Transfer | We report the experimental demonstration of a one-way quantum protocol
reliably operating in the presence of decoherence. Information is protected by
designing an appropriate decoherence-free subspace for a cluster state
resource. We demonstrate our scheme in an all-optical setup, encoding the
information into the pola... | 0708.0960v2 |
2007-08-10 | Qualitative properties of coupled parabolic systems of evolution equations | We apply functional analytical and variational methods in order to study
well-posedness and qualitative properties of evolution equations on product
Hilbert spaces. To this aim we introduce an algebraic formalism for matrices of
sesquilinear mappings. We apply our results to parabolic problems of different
nature: a co... | 0708.1428v2 |
2007-09-06 | Nonequilibrium Electron Interactions in Metal Films | Ultrafast relaxation dynamics of an athermal electron distribution is
investigated in silver films using a femtosecond pump-probe technique with 18
fs pulses in off-resonant conditions. The results yield evidence for an
increase with time of the electron-gas energy loss rate to the lattice and of
the free electron damp... | 0709.0815v1 |
2007-09-24 | Quasinormal Modes and Late-Time Tails of Canonical Acoustic Black Holes | In this paper, we investigate the evolution of classical wave propagation in
the canonical acoustic black hole by numerical method and discuss the details
of tail phenomenon. The oscillating frequency and damping time scale both
increase with the angular momentum $l$. For the lower $l$, numerical results
show the lowes... | 0709.3714v1 |
2007-10-03 | Grain Boundary Diffusion in a Peierls-Nabarro Potential | We investigate the diffusion of a grain boundary in a crystalline material.
We consider in particular the case of a regularly spaced low-angle grain
boundary schematized as an array of dislocations that interact with each other
through long-range stress fields and with the crystalline Peierls-Nabarro
potential. The met... | 0710.0807v1 |
2007-10-04 | Effect of Impurity Scattering on the Nonlinear Microwave Response in High-Tc Superconductors | We theoretically investigate intermodulation distortion in high-Tc
superconductors. We study the effect of nonmagnetic impurities on the real and
imaginary parts of nonlinear conductivity. The nonlinear conductivity is
proportional to the inverse of temperature owing to the dependence of the
damping effect on energy, w... | 0710.0934v1 |
2007-10-15 | Ferromagnetic resonance study of polycrystalline Fe_{1-x}V_x alloy thin films | Ferromagnetic resonance has been used to study the magnetic properties and
magnetization dynamics of polycrystalline Fe$_{1-x}$V$_{x}$ alloy films with
$0\leq x < 0.7$. Films were produced by co-sputtering from separate Fe and V
targets, leading to a composition gradient across a Si substrate. FMR studies
were conducte... | 0710.2826v2 |
2007-10-20 | Khasminskii--Whitham averaging for randomly perturbed KdV equation | We consider the damped-driven KdV equation $$ \dot
u-\nu{u_{xx}}+u_{xxx}-6uu_x=\sqrt\nu \eta(t,x), x\in S^1, \int u dx\equiv
\int\eta dx\equiv0, $$ where $0<\nu\le1$ and the random process $\eta$ is
smooth in $x$ and white in $t$. For any periodic function $u(x)$ let $
I=(I_1,I_2,...) $ be the vector, formed by the KdV... | 0710.3869v1 |
2007-10-25 | Casimir energy and entropy between dissipative mirrors | We discuss the Casimir effect between two identical, parallel slabs,
emphasizing the role of dissipation and temperature. Starting from quite
general assumptions, we analyze the behavior of the Casimir entropy in the
limit T->0 and link it to the behavior of the slab's reflection coefficients at
low frequencies. We als... | 0710.4915v2 |
2007-10-29 | Nonlinear damping of slab modes and cosmic ray transport | By applying recent results for the slab correlation time scale onto cosmic
ray scattering theory, we compute cosmic ray parallel mean free paths within
the quasilinear limit. By employing these results onto charged particle
transport in the solar system, we demonstrate that much larger parallel mean
free paths can be o... | 0710.5418v1 |
2007-10-30 | Dynamics of a 1-D model for the emergence of the plasma edge shear flow layer with momentum conserving Reynolds stress | A one-dimensional version of the second-order transition model based on the
sheared flow amplification by Reynolds stress and turbulence supression by
shearing is presented. The model discussed in this paper includes a form of the
Reynolds stress which explicitly conserves momentum. A linear stability
analysis of the c... | 0710.5612v1 |
2007-11-10 | A magnetization equation for non-equilibrium spin systems | A magnetization equation for a system of spins evolving non-adiabatically and
out of equilibrium is derived without specifying the internal interactions. For
relaxation processes, this equation provides a general form of magnetization
damping. A special case of the spin-spin exchange interaction is considered. | 0711.1576v1 |
2007-11-13 | Non-local dynamics of Bell states in separate cavities | We present non-local dynamics of Bell states in separate cavities. It is
demonstrated that (i) the entanglement damping speed will saturate when the
cavity leakage rate $\gamma\geq 0.4$; (ii) the synchronism relationship between
the fidelity and the concurrence depends on the initial state; (iii) if the
initial state i... | 0711.1923v1 |
2007-11-14 | Isolated large amplitude periodic motions of towed rigid wheels | This study investigates a low degree-of-freedom (DoF) mechanical model of
shimmying wheels. The model is studied using bifurcation theory and numerical
continuation. Self-excited vibrations, that is, stable and unstable periodic
motions of the wheel, are detected with the help of Hopf bifurcation
calculations. These os... | 0711.2228v1 |
2007-11-21 | Power Processing Circuits for Mems Inertial Energy Scavengers | Inertial energy scavengers are self-contained devices which generate power
from ambient motion, by electrically damping the internal motion of a suspended
proof mass. There are significant challenges in converting the power generated
from such devices to useable form, particularly in micro-engineered variants.
This pap... | 0711.3311v1 |
2007-11-21 | Scaling Effects for Electromagnetic Vibrational Power Generators | This paper investigates how the power generated by electromagnetic based
vibrational power generators scales with the dimension of the generator. The
effects of scaling on the magnetic fields, the coil parameters and the
electromagnetic damping are presented. An analysis is presented for both
wire-wound coil technology... | 0711.3316v1 |
2007-11-30 | Large voltage from spin pumping in magnetic tunnel junctions | We studied the response of a ferromagnet-insulator-normal metal tunnel
structure under an external oscillating radio frequency (R.F.) magnetic field.
The D. C. voltage across the junction is calculated and is found not to
decrease despite the high resistance of the junction; instead, it is of the
order of $\mu V$ to $1... | 0711.4939v1 |
2007-12-01 | Description of current-driven torques in magnetic tunnel junctions | A free electron description of spin-dependent tranport in magnetic tunnel
junctions with non collinear magnetizations is presented. We investigate the
origin of transverse spin density in tunnelling transport and the quantum
interferences which give rise to oscillatory torques on the local
magnetization. Spin transfer ... | 0712.0055v1 |
2007-12-10 | Pathways through interstellar matter: - From the closest stars to the most distant quasars | Observations of quasar absorption systems relevant for studies of star
formation at redshift 2 </= z </= 4 are briefly reviewed. Emphasis is given on
the role played by dust in our understanding of the star formation history of
galaxies detected as absorption systems. Local interstellar studies are used as
a reference ... | 0712.1418v1 |
2007-12-17 | Exact time-average distribution for a stationary non-Markovian massive Brownian particle coupled to two heat baths | Using a time-averaging technique we obtain exactly the probability
distribution for position and velocity of a Brownian particle under the
influence of two heat baths at different temperatures. These baths are
expressed by a white noise term, representing the fast dynamics, and a colored
noise term, representing the sl... | 0712.2839v1 |
2007-12-19 | Hyperon bulk viscosity in the presence of antikaon condensate | We investigate the hyperon bulk viscosity due to the non-leptonic process $n
+ p \rightleftharpoons p + \Lambda $ in $K^-$ condensed matter and its effect
on the r-mode instability in neutron stars. We find that the hyperon bulk
viscosity coefficient in the presence of antikaon condensate is suppressed
compared with th... | 0712.3171v2 |
2007-12-31 | Exact Solution of the Landau-Lifshitz Equations for a Radiating Charged Particle in The Coulomb Potential | We solve exactly the classical non-relativistic Landau-Lifshitz equations of
motion for a charged particle moving in a Coulomb potential, including
radiation damping. The general solution involves the Painleve transcendent of
type II. It confirms our physical intuition that a negatively charged classical
particle will ... | 0801.0238v2 |
2008-01-16 | Charge and Spin Currents Generated by Dynamical Spins | We demonstrate theoretically that a charge current and a spin current are
generated by spin dynamics in the presence of spin-orbit interaction in the
perturbative regime. We consider a general spin-orbit interaction including the
spatially inhomogeneous case. Spin current due to spin damping is identified as
one origin... | 0801.2466v2 |
2008-01-16 | Dynamic stabilization of non-spherical bodies against unlimited collapse | We solve equations, describing in a simplified way the newtonian dynamics of
a selfgravitating nonrotating spheroidal body after loss of stability. We find
that contraction to a singularity happens only in a pure spherical collapse,
and deviations from the spherical symmetry stop the contraction by the
stabilising acti... | 0801.2538v1 |
2008-01-30 | Effective theory of fluctuating circulating currents in high-Tc cuprates | We derive an effective dissipative quantum field theory for fluctuating
orbital currents in clean $CuO_2$ sheets of high-$T_c$ cuprates, based on a
three-band model. The Coulomb repulsion term between $Cu$- and $O$-sites is
decoupled in terms of current operators representing horizontal and vertical
parts of circulatin... | 0801.4611v1 |
2008-02-04 | Nodal quasiparticles and the onset of spin density wave order in the cuprates | We present a theory for the onset of spin density wave order in the
superconducting ground state of the cuprates. We compute the scaling dimensions
of allowed perturbations of a `relativistic' fixed point with O(4)xO(3)
symmetry, including those associated with the fermionic nodal Bogoliubov
quasiparticles. Analyses of... | 0802.0199v1 |
2008-02-08 | Rate of decoherence for an electron weakly coupled to a phonon gas | We study the dynamics of an electron weakly coupled to a phonon gas. The
initial state of the electron is the superposition of two spatially localized
distant bumps moving towards each other, and the phonons are in a thermal
state. We investigate the dynamics of the system in the kinetic regime and show
that the time e... | 0802.1229v1 |
2008-02-11 | Massive Charged Scalar Quasinormal Modes of Reissner-Nördstrom Black Hole Surrounded by Quintessence | We evaluate the complex frequencies of the normal modes for the massive
charged scalar field perturbations around a Reissner-N\"ordstrom black hole
surrounded by a static and spherically symmetric quintessence using third order
WKB approximation approach. Due to the presence of quintessence, quasinormal
frequencies dam... | 0802.1397v1 |
2008-02-22 | Algebraic Structure of a Master Equation with Generalized Lindblad Form | The quantum damped harmonic oscillator is described by the master equation
with usual Lindblad form. The equation has been solved completely by us in
arXiv : 0710.2724 [quant-ph]. To construct the general solution a few facts of
representation theory based on the Lie algebra $su(1,1)$ were used.
In this paper we trea... | 0802.3252v1 |
2008-02-22 | Environmental limits on the non-resonant cosmic-ray current-driven instability | We investigate the so-called non-resonant cosmic-ray streaming instability,
first discussed by Bell (2004). The extent to which thermal damping and
ion-neutral collisions reduce the growth of this instability is calculated.
Limits on the growth of the non-resonant mode in SN1006 and RX J1713.7-3946 are
presented. | 0802.3322v1 |
2008-03-04 | The decreasing property of relative entropy and the strong superadditivity of quantum channels | We argue that a fundamental (conjectured) property of memoryless quantum
channels, namely the strong superadditivity, is intimately related to the
decreasing property of the quantum relative entropy. Using the latter we first
give, for a wide class of input states, an estimation of the output entropy for
phase damping ... | 0803.0452v2 |
2008-03-08 | The Impact of Stochastic Primordial Magnetic Fields on the Scalar Contribution to Cosmic Microwave Background Anisotropies | We study the impact of a stochastic background of primordial magnetic fields
on the scalar contribution of CMB anisotropies and on the matter power
spectrum. We give the correct initial conditions for cosmological perturbations
and the exact expressions for the energy density and Lorentz force associated
to the stochas... | 0803.1246v1 |
2008-03-13 | Dynamical density functional theory with hydrodynamic interactions and colloids in unstable traps | A density functional theory for colloidal dynamics is presented which
includes hydrodynamic interactions between the colloidal particles. The theory
is applied to the dynamics of colloidal particles in an optical trap which
switches periodically in time from a stable to unstable confining potential. In
the absence of h... | 0803.2009v1 |
2008-03-26 | Damping of Type I X-ray Burst Oscillations by Convection | I construct a simple model of the convective burning layer during a type I
X-ray burst to investigate the effects convection has on the stability of the
layer to nonradial oscillations. A linear perturbation analysis demonstrates
that the region is stable to nonradial oscillations when energy transport is
convection-do... | 0803.3814v2 |
2008-03-28 | Dipole Oscillations of a Bose-Einstein Condensate in Presence of Defects and Disorder | We consider dipole oscillations of a trapped dilute Bose-Einstein condensate
in the presence of a scattering potential consisting either in a localized
defect or in an extended disordered potential. In both cases the breaking of
superfluidity and the damping of the oscillations are shown to be related to
the appearance... | 0803.4116v1 |
2008-03-28 | Atomic Zitterbewegung | Ultra-cold atoms which are subject to ultra-relativistic dynamics are
investigated. By using optically induced gauge potentials we show that the
dynamics of the atoms is governed by a Dirac type equation. To illustrate this
we study the trembling motion of the centre of mass for an effective two level
system, historica... | 0803.4189v2 |
2008-04-01 | Passive Convection of Density Fluctuations in the Local Interstellar Medium | We have developed a time-dependent three-dimensional model of isotropic,
adiabatic, and compressible magnetohydrodynamic plasma to understand nonlinear
cascades of density fluctuations in local interstellar medium. Our simulations,
describing evolution of initial supersonic, super Alfv\'enic plasma modes,
indicate that... | 0804.0045v1 |
2008-04-02 | Anomalous quantum reflection as a quasi-dynamical damping effect | We develop a quasi-analytical theory for the quantum reflection amplitude of
Bose-Einstein condensates. We derive and calculate the decay-width of a
Bose-Einstein condensate. A general relation between the time-dependent
decay-law of the system and its quantum reflection amplitude allows us to
explain the quantum refle... | 0804.0367v2 |
2008-04-10 | Colliding solitons for the nonlinear Schrodinger equation | We study the collision of two fast solitons for the nonlinear Schr\"odinger
equation in the presence of a spatially adiabatic external potential. For a
high initial relative speed $\|v\|$ of the solitons, we show that, up to times
of order $\log\|v\|$ after the collision, the solitons preserve their shape (in
$L^2$-nor... | 0804.1608v1 |
2008-04-10 | Statistical correlations of an anyon liquid at low temperatures | Using a proposed generalization of the pair distribution function for a gas
of non-interacting particles obeying fractional exclusion statistics in
arbitrary dimensionality, we derive the statistical correlations in the
asymptotic limit of vanishing or low temperature. While Friedel-like
oscillations are present in nea... | 0804.1691v1 |
2008-04-11 | Collisional Properties of a Polarized Fermi Gas with Resonant Interactions | Highly polarized mixtures of atomic Fermi gases constitute a novel Fermi
liquid. We demonstrate how information on thermodynamic properties may be used
to calculate quasiparticle scattering amplitudes even when the interaction is
resonant and apply the results to evaluate the damping of the spin dipole mode.
We estimat... | 0804.1885v2 |
2008-04-25 | Impurity induced coherent current oscillations in one-dimensional conductors | We study theoretically the electronic transport through a single impurity in
a repulsive Luttinger liquid (LL), and find that above a threshold voltage
related to a strength of the impurity potential the DC current $\bar I$ is
accompanied by coherent oscillations with frequency $f = \bar I/e$. There is an
analogy with ... | 0804.4113v1 |
2008-05-06 | Wave Decay in MHD Turbulence | We present a model for nonlinear decay of the weak wave in three-dimensional
incompressible magnetohydrodynamic (MHD) turbulence. We show that the decay
rate is different for parallel and perpendicular waves. We provide a general
formula for arbitrarily directed waves and discuss particular limiting cases
known in the ... | 0805.0630v1 |
2008-05-07 | A piecewise-linear reduced-order model of squeeze-film damping for deformable structures including large displacement effects | This paper presents a reduced-order model for the Reynolds equation for
deformable structure and large displacements. It is based on the model
established in [11] which is piece-wise linearized using two different methods.
The advantages and drawbacks of each method are pointed out. The pull-in time
of a microswitch is... | 0805.0894v1 |
2008-05-14 | Signal propagation through dense granular systems | The manner in which signals propagate through dense granular systems in both
space and time is not well understood. In order to learn more about this
process, we carry out discrete element simulations of the system response to
excitations where we control the driving frequency and wavelength
independently. Fourier anal... | 0805.2051v1 |
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