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47
2006-12-07
On some peculiarities of electric field pulse propagation in electron Maxwellian plasma and its back response
In the spirit of continued study of general plasma wave properties we investigated the boundary problem with the simplest form of electric field pulse at the edge x=0 of half-infinite uniform plasma slab with Maxwellian electron distribution function. In the case of longitudinal electric field pulse its traveling veloc...
0612064v4
2007-01-30
Charge Fluctuation of Dust Grain and Its Impact on Dusty-Acoustic Wave Damping
We consider the influence of dust charge fluctuations on damping of the dust-ion-acoustic waves. It is assumed that all grains have equal masses but charges are not constant in time - they may fluctuate in time. The dust charges are not really independent of the variations in the plasma potentials. All modes will influ...
0701336v1
1996-10-29
Bosonic Quantum Codes for Amplitude Damping
Traditional quantum error correction involves the redundant encoding of k quantum bits using n quantum bits to allow the detection and correction of any t bit error. The smallest general t=1 code requires n=5 for k=1. However, the dominant error process in a physical system is often well known, thus inviting the questi...
9610043v1
1997-01-16
Cooperative loss and decoherence in quantum computation and commuication
Cooperative effects in the loss (the amplitude damping) and decoherence (the phase damping) of the qubits (two-state quantum systems) due to the inevitable coupling to the same environment are investigated. It is found that the qubits undergo the dissipation coherently in this case. In particular, for a special kind of...
9701020v1
1997-03-22
Preserving coherence in quantum computation by pairing quantum bits
A scheme is proposed for protecting quantum states from both independent decoherence and cooperative decoherence. The scheme operates by pairing each qubit (two-state quantum system) with an ancilla qubit and by encoding the states of the qubits into the corresponding coherence-preserving states of the qubit-pairs. In ...
9703040v2
1997-06-10
Perturbative expansions for the fidelities and spatially correlated dissipation of quantum bits
We construct generally applicable short-time perturbative expansions for some fidelities, such as the input-output fidelity, the entanglement fidelity, and the average fidelity. Successive terms of these expansions yield characteristic times for the damping of the fidelities involving successive powers of the Hamiltoni...
9706020v2
1998-05-27
Measurement Process In a Two-Barrier System
The description of a measuring process, such as that which occurs when a quantum point contact (QPC) detector is influenced by a nearby external electron which can take up two possible positions, provides a interesting application of the method of quantum damping. We find a number of new effects, due to the complete tr...
9805081v2
1998-10-06
Cumulant expansion for studying damped quantum solitons
The quantum statistics of damped optical solitons is studied using cumulant-expansion techniques. The effect of absorption is described in terms of ordinary Markovian relaxation theory, by coupling the optical field to a continuum of reservoir modes. After introduction of local bosonic field operators and spatial discr...
9810018v3
1999-02-10
Quantum noise in the position measurement of a cavity mirror undergoing Brownian motion
We perform a quantum theoretical calculation of the noise power spectrum for a phase measurement of the light output from a coherently driven optical cavity with a freely moving rear mirror. We examine how the noise resulting from the quantum back action appears among the various contributions from other noise sources....
9902040v1
1999-10-05
Uncertainty, entropy and decoherence of the damped harmonic oscillator in the Lindblad theory of open quantum systems
In the framework of the Lindblad theory for open quantum systems, expressions for the density operator, von Neumann entropy and effective temperature of the damped harmonic oscillator are obtained. The entropy for a state characterized by a Wigner distribution function which is Gaussian in form is found to depend only ...
9910019v1
2000-06-07
Phenomenological approach to introduce damping effects on radiation field states
In this work we propose an approach to deal with radiation field states which incorporates damping effects at zero temperature. By using some well known results on dissipation of a cavity field state, obtained by standard ab-initio methods, it was possible to infer through a phenomenological way the explicit form for t...
0006035v2
2001-09-28
Decoherence in trapped ions due to polarization of the residual background gas
We investigate the mechanism of damping and heating of trapped ions associated with the polarization of the residual background gas induced by the oscillating ions themselves. Reasoning by analogy with the physics of surface electrons in liquid helium, we demonstrate that the decay of Rabi oscillations observed in expe...
0109156v1
2002-06-18
Five Lectures On Dissipative Master Equations
1 First Lecture: Basics 1.1 Physical Derivation of the Master Equation 1.2 Some Simple Implications 1.3 Steady State 1.4 Action to the Left 2 Second Lecture: Eigenvalues and Eigenvectors of L 2.1 A Simple Case First 2.2 The General Case 3 Third Lecture: Completeness of the Damping Bases 3.1 Phase Spac...
0206116v1
2002-10-02
Radiation damping and decoherence in quantum electrodynamics
The processes of radiation damping and decoherence in Quantum Electrodynamics are studied from an open system's point of view. Employing functional techniques of field theory, the degrees of freedom of the radiation field are eliminated to obtain the influence phase functional which describes the reduced dynamics of th...
0210013v1
2003-01-08
Dissipation, Emergent Quantization and Quantum Fluctuations
We review some aspects of the quantization of the damped harmonic oscillator. We derive the exact action for a damped mechanical system in the frame of the path integral formulation of the quantum Brownian motion problem developed by Schwinger and by Feynman and Vernon. The doubling of the phase-space degrees of freedo...
0301031v1
2004-01-28
Bloch Equations and Completely Positive Maps
The phenomenological dissipation of the Bloch equations is reexamined in the context of completely positive maps. Such maps occur if the dissipation arises from a reduction of a unitary evolution of a system coupled to a reservoir. In such a case the reduced dynamics for the system alone will always yield completely po...
0401177v1
2004-02-12
Non-Markovian Quantum Trajectories Versus Master Equations: Finite Temperature Heat Bath
The interrelationship between the non-Markovian stochastic Schr\"odinger equations and the corresponding non-Markovian master equations is investigated in the finite temperature regimes. We show that the general finite temperature non-Markovian trajectories can be used to derive the corresponding non-Markovian master e...
0402086v2
2005-04-27
Decoherence models and their effects on quantum maps and algorithms
In this work we study several models of decoherence and how different quantum maps and algorithms react when perturbed by them. Following closely Ref. [1], generalizations of the three paradigmatic one single qubit quantum channels (these are the depolarizing channel, the phase damping channel and the amplitude damping...
0504211v1
2005-09-22
Semiclassical quantization of non-Hamiltonian dynamical systems without memory
We propose a new method of quantization of a wide class of dynamical systems that originates directly from the equations of motion. The method is based on the correspondence between the classical and the quantum Poisson brackets, postulated by Dirac. This correspondence applied to open (non-Hamiltonian) systems allows ...
0509159v1
2005-11-15
Classical Phase Space Density for the Relativistic Hydrogen Atom
Quantum mechanics is considered to arise from an underlying classical structure (``hidden variable theory'', ``sub-quantum mechanics''), where quantum fluctuations follow from a physical noise mechanism. The stability of the hydrogen ground state can then arise from a balance between Lorentz damping and energy absorpti...
0511144v1
2006-01-10
Quantum Brownian motion and the Third Law of thermodynamics
The quantum thermodynamic behavior of small systems is investigated in presence of finite quantum dissipation. We consider the archetype cases of a damped harmonic oscillator and a free quantum Brownian particle. A main finding is that quantum dissipation helps to ensure the validity of the Third Law. For the quantum o...
0601056v1
2006-03-13
Decoherence induced by a phase-damping reservoir
A phase damping reservoir composed by $N$-bosons coupled to a system of interest through a cross-Kerr interaction is proposed and its effects on quantum superpo sitions are investigated. By means of analytical calculations we show that: i-) the reservoir induces a Gaussian decay of quantum coherences, and ii-) the inhe...
0603109v2
2007-01-21
Casimir-Polder forces on excited atoms in the strong atom-field coupling regime
Based on macroscopic quantum electrodynamics in linear media, we develop a general theory of the resonant Casimir-Polder force on an excited two-level atom in the presence of arbitrary linear bodies, with special emphasis on the strong-coupling regime where reabsorption of an emitted photon can give rise to (vacuum) Ra...
0701151v2
2007-02-07
Protecting an optical qubit against photon loss
We consider quantum error-correction codes for multimode bosonic systems, such as optical fields, that are affected by amplitude damping. Such a process is a generalization of an erasure channel. We demonstrate that the most accessible method of transforming optical systems with the help of passive linear networks has ...
0702075v1
1995-02-03
Shock waves in the dissipative Toda lattice
We consider the propagation of a shock wave (SW) in the damped Toda lattice. The SW is a moving boundary between two semi-infinite lattice domains with different densities. A steadily moving SW may exist if the damping in the lattice is represented by an ``inner'' friction, which is a discrete analog of the second visc...
9502001v1
2007-04-04
An integral field spectroscopic survey for high redshift damped Lyman-alpha galaxies
We search for galaxy counterparts to damped Lyman-alpha absorbers (DLAs) at z>2 towards nine quasars, which have 14 DLAs and 8 sub-DLAs in their spectra. We use integral field spectroscopy to search for Ly-alpha emission line objects at the redshifts of the absorption systems. Besides recovering two previously confirme...
0704.0654v1
2007-04-06
9.7 micrometer Silicate Absorption in a Damped Lyman-alpha Absorber at z=0.52
We report a detection of the 9.7 micrometer silicate absorption feature in a damped Lyman-alpha (DLA) system at z_{abs} = 0.524 toward AO0235+164, using the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. The feature shows a broad shallow profile over about 8-12 micrometers in the absorber rest frame a...
0704.0826v2
2007-04-17
Boolean network model predicts cell cycle sequence of fission yeast
A Boolean network model of the cell-cycle regulatory network of fission yeast (Schizosaccharomyces Pombe) is constructed solely on the basis of the known biochemical interaction topology. Simulating the model in the computer, faithfully reproduces the known sequence of regulatory activity patterns along the cell cycle ...
0704.2200v1
2007-05-08
Optical dilution and feedback cooling of a gram-scale oscillator to 6.9 mK
We report on use of a radiation pressure induced restoring force, the optical spring effect, to optically dilute the mechanical damping of a 1 gram suspended mirror, which is then cooled by active feedback (cold damping). Optical dilution relaxes the limit on cooling imposed by mechanical losses, allowing the oscillato...
0705.1018v2
2007-05-14
Electron-muon heat conduction in neutron star cores via the exchange of transverse plasmons
We calculate the thermal conductivity of electrons and muons kappa_{e-mu} produced owing to electromagnetic interactions of charged particles in neutron star cores and show that these interactions are dominated by the exchange of transverse plasmons (via the Landau damping of these plasmons in nonsuperconducting matter...
0705.1963v1
2007-05-24
Measurement of Newtonian fluid slip using a torsional ultrasonic oscillator
The composite torsional ultrasonic oscillator, a versatile experimental system, can be used to investigate slip of Newtonian fluid at a smooth surface. A rigorous analysis of slip-dependent damping for the oscillator is presented. Initially, the phenomenon of finite surface slip and the slip length are considered for a...
0705.3498v3
2007-06-05
Waves and instabilities in dissipative rotating superfluid neutron stars
We discuss wave propagation in rotating superfluid neutron star cores, taking into account the vortex mediated mutual friction force. For models where the two fluids co-rotate in the unperturbed state, our analysis clarifies the role of chemical coupling and entrainment for sound and inertial waves. We also investigate...
0706.0672v1
2007-07-20
Dissipation-Scale Turbulence in the Solar Wind
We present a cascade model for turbulence in weakly collisional plasmas that follows the nonlinear cascade of energy from the large scales of driving in the MHD regime to the small scales of the kinetic Alfven wave regime where the turbulence is dissipated by kinetic processes. Steady-state solutions of the model for t...
0707.3149v1
2007-08-09
An algorithm for detecting oscillatory behavior in discretized data: the damped-oscillator oscillator detector
We present a simple algorithm for detecting oscillatory behavior in discrete data. The data is used as an input driving force acting on a set of simulated damped oscillators. By monitoring the energy of the simulated oscillators, we can detect oscillatory behavior in data. In application to in vivo deep brain basal gan...
0708.1341v1
2007-08-22
The dynamics of vortex generation in superfluid 3He-B
A profound change occurs in the stability of quantized vortices in externally applied flow of superfluid 3He-B at temperatures ~ 0.6 Tc, owing to the rapidly decreasing damping in vortex motion with decreasing temperature. At low damping an evolving vortex may become unstable and generate a new independent vortex loop....
0708.3003v2
2007-08-26
Geodesic plasma flows instabilities of Riemann twisted solar loops
Riemann and sectional curvatures of magnetic twisted flux tubes in Riemannian manifold are computed to investigate the stability of the plasma astrophysical tubes. The geodesic equations are used to show that in the case of thick magnetic tubes, the curvature of planar (Frenet torsion-free) tubes have the effect ct of ...
0708.3473v1
2007-09-05
Phonon bottleneck in the low-excitation limit
The phonon-bottleneck problem in the relaxation of two-level systems (spins) via direct phonon processes is considered numerically in the weak-excitation limit where the Schroedinger equation for the spin-phonon system simplifies. The solution for the relaxing spin excitation p(t), emitted phonons n_k(t), etc. is obtai...
0709.0556v1
2007-09-13
Distribution of PageRank Mass Among Principle Components of the Web
We study the PageRank mass of principal components in a bow-tie Web Graph, as a function of the damping factor c. Using a singular perturbation approach, we show that the PageRank share of IN and SCC components remains high even for very large values of the damping factor, in spite of the fact that it drops to zero whe...
0709.2016v1
2007-10-02
Oscillating Starless Cores: The Nonlinear Regime
In a previous paper, we modeled the oscillations of a thermally-supported (Bonnor-Ebert) sphere as non-radial, linear perturbations following a standard analysis developed for stellar pulsations. The predicted column density variations and molecular spectral line profiles are similar to those observed in the Bok globul...
0710.0625v1
2007-10-08
Jet quenching parameter \hat q in the stochastic QCD vacuum with Landau damping
We argue that the radiative energy loss of a parton traversing the quark-gluon plasma is determined by Landau damping of soft modes in the plasma. Using this idea, we calculate the jet quenching parameter of a gluon. The calculation is done in SU(3) quenched QCD within the stochastic vacuum model. At the LHC-relevant t...
0710.1540v2
2007-11-07
Tuning the effective coupling of an AFM lever to a thermal bath
Fabrication of Nano-Electro-Mechanical-Systems (NEMS) of high quality is nowadays extremely efficient. These NEMS will be used as sensors and actuators in integrated systems. Their use however raises questions about their interface (actuation, detection, read out) with external detection and control systems. Their oper...
0711.1024v1
2007-12-11
Neutrino oscillations in a stochastic model for space-time foam
We study decoherence models for flavour oscillations in four-dimensional stochastically fluctuating space times and discuss briefly the sensitivity of current neutrino experiments to such models. We pay emphasis on demonstrating the model dependence of the associated decoherence-induced damping coefficients in front of...
0712.1779v1
2008-01-21
Collective cyclotron motion of the relativistic plasma in graphene
We present a theory of the finite temperature thermo-electric response functions of graphene, in the hydrodynamic regime induced by electron-electron collisions. In moderate magnetic fields, the Dirac particles undergo a collective cyclotron motion with a temperature-dependent relativistic cyclotron frequency proportio...
0801.2970v3
2008-01-25
Sound waves and solitons in hot and dense nuclear matter
Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density. The equation of state is derived from a relativistic mean field model, which is a variant of the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic ...
0801.3938v1
2008-01-28
Qualitative Analysis of Forced Response of Blisks With Friction Ring Dampers
A damping strategy for blisks (integrally bladed disks) of turbomachinery involving a friction ring is investigated. These rings, located in grooves underside the wheel of the blisks, are held in contact by centrifugal loads and the energy is dissipated when relative motions between the ring and the disk occur. A repre...
0801.4350v1
2008-01-29
Long Term Evolution of Magnetic Turbulence in Relativistic Collisionless Shocks
We study the long term evolution of magnetic fields generated by an initially unmagnetized collisionless relativistic $e^+e^-$ shock. Our 2D particle-in-cell numerical simulations show that downstream of such a Weibel-mediated shock, particle distributions are approximately isotropic, relativistic Maxwellians, and the ...
0801.4583v1
2008-02-20
Mechanical mode dependence of bolometric back-action in an AFM microlever
Two back action (BA) processes generated by an optical cavity based detection device can deeply transform the dynamical behavior of an AFM microlever: the photothermal force or the radiation pressure. Whereas noise damping or amplifying depends on optical cavity response for radiation pressure BA, we present experiment...
0802.2763v2
2008-02-21
Propagation of cosmic rays in the foam-like Universe
The model of a classical spacetime foam is considered, which consists of static wormholes embedded in Minkowski spacetime. We examine the propagation of particles in such a medium and demonstrate that a single thin ray undergoes a specific damping in the density of particles depending on the traversed path and the dist...
0802.3109v2
2008-02-21
Damping by slow relaxing rare earth impurities in Ni80Fe20
Doping NiFe by heavy rare earth atoms alters the magnetic relaxation properties of this material drastically. We show that this effect can be well explained by the slow relaxing impurity mechanism. This process is a consequence of the anisotropy of the on site exchange interaction between the 4f magnetic moments and th...
0802.3206v3
2008-03-11
Domain wall motion of magnetic nanowires under a static field
The propagation of a head-to-head magnetic domain-wall (DW) or a tail-to-tail DW in a magnetic nanowire under a static field along the wire axis is studied. Relationship between the DW velocity and DW structure is obtained from the energy consideration. The role of the energy dissipation in the field-driven DW motion i...
0803.1531v1
2008-03-11
Equation of state for strongly interacting matter: collective effects, Landau damping and predictions for LHC
The equation of state (EOS) is of utmost importance for the description of the hydrodynamic phase of strongly interacting matter in relativistic heavy-ion collisions. Lattice QCD can provide useful information on the EOS, mainly for small net baryon densities. The QCD quasiparticle model provides a means to map lattice...
0803.1571v1
2008-04-04
Spin-charge coupling in a band ferromagnet: magnon-energy reduction, anomalous softening, and damping
The effects of correlation-induced coupling between spin and charge fluctuations on spin-wave excitations in a band ferromagnet are investigated by including self-energy and vertex corrections within a systematic inverse-degeneracy expansion scheme which explicitly preserves the Goldstone mode. Arising from the scatter...
0804.0680v1
2008-05-07
Noise Analysis and Noise-based Optimization for Resonant MEMS Structures
This paper presents a detailed noise analysis and a noise-based optimization procedure for resonant MEMS structures. A design for high sensitivity of MEMS structures needs to take into account the noise shaping induced by damping phenomena at micro scale. The existing literature presents detailed models for the damping...
0805.0927v1
2008-05-07
Scaling crossovers in activated escape of nonequilibrium systems: a resonantly driven oscillator
The rate of metastable decay in nonequilibrium systems is expected to display scaling behavior: i.e., the logarithm of the decay rate should scale as a power of the distance to a bifurcation point where the metastable state disappears. Recently such behavior was observed and some of the earlier predicted exponents were...
0805.0972v2
2008-05-07
Quantum Noise, Effective Temperature, and Damping in a Superconducting Single-Electron Transistor
We have directly measured the quantum noise of a superconducting single-electron transistor (S-SET) embedded in a microwave resonator consisting of a superconducting LC tank circuit. Using an effective bath description, we find that the S-SET provides damping of the resonator modes proportional to its differential cond...
0805.1037v1
2008-05-08
Adaptive Affinity Propagation Clustering
Affinity propagation clustering (AP) has two limitations: it is hard to know what value of parameter 'preference' can yield an optimal clustering solution, and oscillations cannot be eliminated automatically if occur. The adaptive AP method is proposed to overcome these limitations, including adaptive scanning of prefe...
0805.1096v1
2008-06-06
On the stability of shocks with particle pressure
We perform a linear stability analysis for corrugations of a Newtonian shock, with particle pressure included, for an arbitrary diffusion coefficient. We study first the dispersion relation for homogeneous media, showing that, besides the conventional pressure waves and entropy/vorticity disturbances, two new perturbat...
0806.1113v1
2008-06-17
Damping of Fast Magnetohydrodynamic Oscillations in Quiescent Filament Threads
High-resolution observations provide evidence about the existence of small-amplitude transverse oscillations in solar filament fine structures. These oscillations are believed to represent fast magnetohydrodynamic (MHD) waves and the disturbances are seen to be damped in short timescales of the order of 1 to 4 periods....
0806.2728v1
2008-06-27
Global attractor and asymptotic smoothing effects for the weakly damped cubic Schrödinger equation in $L^2(\T)$
We prove that the weakly damped cubic Schr\"odinger flow in $L^2(\T)$ provides a dynamical system that possesses a global attractor. The proof relies on a sharp study of the behavior of the associated flow-map with respect to the weak $ L^2(\T) $-convergence inspired by a previous work of the author. Combining the comp...
0806.4578v3
2008-06-30
Thermal depinning of fluxons in discrete Josephson rings
We study the thermal depinning of single fluxons in rings made of Josephson junctions. Due to thermal fluctuations a fluxon can be excited from its energy minima and move through the array, causing a voltage across each junction. We find that for the initial depinning, the fluxon behaves as a single particle and follow...
0806.4828v1
2008-07-03
Dependence of the decoherence of polarization states in phase-damping channels on the frequency spectrum envelope of photons
We consider the decoherence of photons suffering in phase-damping channels. By exploring the evolutions of single-photon polarization states and two-photon polarization-entangled states, we find that different frequency spectrum envelopes of photons induce different decoherence processes. A white frequency spectrum can...
0807.0536v3
2008-07-17
Planetary Migration in Resonance, the question of the Eccentricities : Les Houches contribution
The formation of resonant planets pairs in exoplanetary systems involves planetary migration inside the protoplanetary disc : an inwards migrating outer planet captures in Mean Motion Resonance an inner planet. During the migration of the resonant pair of planets, the eccentricities are expected to rise excessively, if...
0807.2828v2
2008-07-18
Heavily Damped Motion of One-Dimensional Bose Gases in an Optical Lattice
We study the dynamics of strongly correlated one-dimensional Bose gases in a combined harmonic and optical lattice potential subjected to sudden displacement of the confining potential. Using the time-evolving block decimation method, we perform a first-principles quantum many-body simulation of the experiment of Ferti...
0807.2898v2
2008-07-21
Mutual friction in a cold color flavor locked superfluid and r-mode instabilities in compact stars
Dissipative processes acting in rotating neutron stars are essential in preventing the growth of the r-mode instability. We estimate the damping time of r-modes of an hypothetical compact quark star made up by color flavor locked quark matter at a temperature $T \lesssim 0.01$ MeV. The dissipation that we consider is d...
0807.3264v2
2008-07-23
Dynamical Backaction of Microwave Fields on a Nanomechanical Oscillator
We measure the response and thermal motion of a high-Q nanomechanical oscillator coupled to a superconducting microwave cavity in the resolved-sideband regime where the oscillator's resonance frequency exceeds the cavity's linewidth. The coupling between the microwave field and mechanical motion is strong enough for ra...
0807.3585v3
2008-07-28
Shear Viscosity of the outer crust of Neutron stars: Ion Contribution
The shear viscosity of the crust might have a damping effect on the amplitude of r-modes of rotating neutron stars. This damping has implications for the emission of gravitational waves. We calculate the contribution to the shear viscosity coming from the ions using both semi-analytical methods, that consider binary co...
0807.4353v2
2008-07-28
Unusual decoherence in qubit measurements with a Bose-Einstein condensate
We consider an electrostatic qubit located near a Bose-Einstein condensate (BEC) of noninteracting bosons in a double-well potential, which is used for qubit measurements. Tracing out the BEC variables we obtain a simple analytical expression for the qubit's density-matrix. The qubit's evolution exhibits a slow ($\prop...
0807.4440v2
2008-08-03
Superradiant Instability of Five-Dimensional Rotating Charged AdS Black Holes
We study the instability of small AdS black holes with two independent rotation parameters in minimal five-dimensional gauged supergravity to massless scalar perturbations. We analytically solve the Klein-Gordon equation for low-frequency perturbations in two regions of the spacetime of these black holes: namely, in th...
0808.0280v3
2008-08-15
Collective excitations in two-dimensional antiferromagnet in strong magnetic field
We discuss spin-$\frac12$ two-dimensional (2D) Heisenberg antiferromagnet (AF) on a square lattice at T=0 in strong magnetic field H near its saturation value $H_c$. A perturbation approach is proposed to obtain spectrum of magnons with momenta not very close to AF vector in the leading order in small parameter $(H_c-H...
0808.2127v3
2008-08-26
Nonlinear regularization techniques for seismic tomography
The effects of several nonlinear regularization techniques are discussed in the framework of 3D seismic tomography. Traditional, linear, $\ell_2$ penalties are compared to so-called sparsity promoting $\ell_1$ and $\ell_0$ penalties, and a total variation penalty. Which of these algorithms is judged optimal depends on ...
0808.3472v3
2008-09-09
Process tomography of field damping and measurement of Fock state lifetimes by quantum non-demolition photon counting in a cavity
The relaxation of a quantum field stored in a high-$Q$ superconducting cavity is monitored by non-resonant Rydberg atoms. The field, subjected to repetitive quantum non-demolition (QND) photon counting, undergoes jumps between photon number states. We select ensembles of field realizations evolving from a given Fock st...
0809.1511v1
2008-10-01
Excitation of trapped oscillations in discs around black holes
High-frequency quasi-periodic oscillations detected in the light curves of black hole candidates can, according to one model, be identified with hydrodynamic oscillations of the accretion disc. We describe a non-linear coupling mechanism, suggested by Kato, through which inertial waves trapped in the inner regions of a...
0810.0116v1
2008-10-09
Atomistic spin dynamics of the CuMn spin glass alloy
We demonstrate the use of Langevin spin dynamics for studying dynamical properties of an archetypical spin glass system. Simulations are performed on CuMn (20% Mn) where we study the relaxation that follows a sudden quench of the system to the low temperature phase. The system is modeled by a Heisenberg Hamiltonian whe...
0810.1645v1
2008-10-20
On the Existence of Exponentially Decreasing Solutions of the Nonlinear Landau Damping Problem
In this paper we prove the existence of a large class of periodic solutions of the Vlasov-Poisson in one space dimension that decay exponentially as t goes to infinity. The exponential decay is well known for the linearized version of the Landau damping problem and it has been proved in [4] for a class of solutions of ...
0810.3456v2
2008-10-22
Thermal (in)stability of type I collagen fibrils
We measured Young's modulus at temperatures ranging from 20 to 100 ^{\circ}$C for a collagen fibril taken from rat's tendon. The hydration change under heating and the damping decrement were measured as well. At physiological temperatures $25-45^{\circ}$C Young's modulus decreases, which can be interpreted as instabili...
0810.4172v1
2008-11-03
Ion thermal effects in oscillating multi-ion plasma sheath theory
The effects of ion temperature are discussed in a two-ion electron plasma and for a model applicable to the oscillating sheath theory that has recently been much in the focus of researchers. The differences between the fluid and kinetic models have been pointed out, as well as the differences between the approximative ...
0811.0251v1
2008-12-01
Self-Diffusion in 2D Dusty Plasma Liquids: Numerical Simulation Results
We perform Brownian dynamics simulations for studying the self-diffusion in two-dimensional (2D) dusty plasma liquids, in terms of both mean-square displacement and velocity autocorrelation function (VAF). Super-diffusion of charged dust particles has been observed to be most significant at infinitely small damping rat...
0812.0338v3
2008-12-11
Reduced nonlinear description of Farley-Buneman instability
In the study on nonlinear wave-wave processes in an ionosphere and a magnetosphere usually the main attention is paid to investigation of plasma turbulence at well developed stage, when the wide spectrum of plasma wave is present. On the other side, it is well known that even if the number of cooperating waves remains ...
0812.2182v1
2008-12-16
Reconstructing Baryon Oscillations: A Lagrangian Theory Perspective
Recently Eisenstein and collaborators introduced a method to `reconstruct' the linear power spectrum from a non-linearly evolved galaxy distribution in order to improve precision in measurements of baryon acoustic oscillations. We reformulate this method within the Lagrangian picture of structure formation, to better u...
0812.2905v3
2009-01-28
Location- and observation time-dependent quantum-tunneling
We investigate quantum tunneling in a translation invariant chain of particles. The particles interact harmonically with their nearest neighbors, except for one bond, which is anharmonic. It is described by a symmetric double well potential. In the first step, we show how the anharmonic coordinate can be separated from...
0901.4518v1
2009-02-16
Plasmon excitations in homogeneous neutron star matter
We study the possible collective plasma modes which can affect neutron-star thermodynamics and different elementary processes in the baryonic density range between nuclear saturation ($\rho_0$) and $3\rho_0$. In this region, the expected constituents of neutron-star matter are mainly neutrons, protons, electrons and mu...
0902.2552v2
2009-02-27
Monogamy Inequality and Residual Entanglement of Three Qubits under Decoherence
Exploring an analytical expression for the convex roof of the pure state squared concurrence for rank 2 mixed states the entanglement of a system of three particles under decoherence is studied, using the monogamy inequality for mixed states and the residual entanglement obtained from it. The monogamy inequality is inv...
0903.0019v2
2009-03-12
X-band crab cavities for the CLIC beam delivery system
The CLIC machine incorporates a 20 mrad crossing angle at the IP to aid the extraction of spent beams. In order to recover the luminosity lost through the crossing angle a crab cavity is proposed to rotate the bunches prior to collision. The crab cavity is chosen to have the same frequency as the main linac (11.9942 GH...
0903.2116v1
2009-03-16
Regularity of invariant sets in semilinear damped wave equations
Under fairly general assumptions, we prove that every compact invariant subset $\mathcal I$ of the semiflow generated by the semilinear damped wave equation \epsilon u_{tt}+u_t+\beta(x)u-\sum_{ij}(a_{ij} (x)u_{x_j})_{x_i}&=f(x,u),&& (t,x)\in[0,+\infty[\times\Omega, u&=0,&&(t,x)\in[0,+\infty[\times\partial\Omega in $H^1...
0903.2782v1
2009-03-20
Hawking-Unruh radiation as irreversible consequence of radiative action in dynamics
Hawking-Unruh thermal state of warm surrounding field encountered in non-inertial frames is shown to be a real phenomenon, a marker of nonstationary dynamic evolutions. In accelerated motion of a charged particle it is shown that the recoiled damping effect of Larmor radiation relaxation leads to distinctive thermal po...
0903.3529v2
2009-03-25
The covering factor of high redshift damped Lyman-$α$ systems
We have used the Very Long Baseline Array to image 18 quasars with foreground damped Lyman-$\alpha$ systems (DLAs) at 327, 610 or 1420 MHz, to measure the covering factor $f$ of each DLA at or near its redshifted HI 21cm line frequency. Including six systems from the literature, we find that none of 24 DLAs at $0.09 < ...
0903.4483v1
2009-04-15
Size dependent Acoustic Phonon Dynamics of CdTe0.68Se0.32 Nanoparticles in Borosilicate glass
Low frequency acoustic vibration and phonon linewidth for CdTe0.68Se0.32 nanoparticle embedded in borosilicate glass are calculated using two different approaches by considering the elastic continuum model and fixed boundary condition. The presence of medium significantly affects the phonon peaks and results into the b...
0904.2278v1
2009-04-19
Incorporating Human Body Mass in Standards of Helmet Impact Protection against Traumatic Brain Injury
Impact induced traumatic brain injury (ITBI) describes brain injury from head impact not necessarily accompanied by skull fracture. For sufficiently abrupt head impact decelerations, ITBI results from brain tissue stress incurred as the brain crashes into the inside of the skull wall, displacing the surrounding cerebra...
0904.2856v1
2009-04-21
Type II migration of planets on eccentric orbits
The observed extrasolar planets possess both large masses (with a median M sin i of 1.65 MJ) and a wide range in orbital eccentricity (0 < e < 0.94). As planets are thought to form in circumstellar disks, one important question in planet formation is determining whether, and to what degree, a gaseous disk affects an ec...
0904.3336v1
2009-05-13
J-transform applied to the detection of Gravitational Waves: preliminary results
We propose to apply to the detection of Gravitational Waves a new method developed for the spectral analysis of noisy time-series of damped oscillators. From the Pad\'e Approximations of the time-series Z-transform, a Jacobi Matrix (J-Matrix) is constructed. We show that the J-Matrix has bound states with eigenvalues...
0905.2000v1
2009-05-25
Non-Markovian dynamics of a biased qubit coupled to a structured bath
A new analytical approach, beyond rotating wave approximation, based on unitary transformations and the non-Markovian master equation for the density operator, is applied to treat the biased spin boson model with a Lorentzian structured bath for arbitrary detunings at zero temperature. Compared to zero bias, we find th...
0905.3965v3
2009-05-28
A black box method for solving the complex exponentials approximation problem
A common problem, arising in many different applied contexts, consists in estimating the number of exponentially damped sinusoids whose weighted sum best fits a finite set of noisy data and in estimating their parameters. Many different methods exist to this purpose. The best of them are based on approximate Maximum Li...
0905.4602v2
2009-06-10
GALEX Discovery of a Damped Ly-alpha System at Redshift z = 1
We report the first discovery of a QSO damped Ly-alpha (DLA) system by the GALEX satellite. The system was initially identified as an MgII absorption-line system (z_abs=1.028) in the spectrum of SDSS QSO J0203-0910 (z_em=1.58). The presence of unusually strong absorption due to metal lines of ZnII, CrII, MnII, and FeII...
0906.2018v1
2009-06-11
Longitudinal Stability of Recycler Bunches; Part I: Thresholds for Loss of Landau Damping
We examine the stability of intense flat bunches in barrier buckets used in the Recycler. We consider some common stationary distributions and show that they would be unstable against rigid dipole oscillations. We then discuss an analytical model for the line density that best describes measured bunch profiles. We incl...
0906.2188v1
2009-06-15
Regge poles of the Schwarzschild black hole: a WKB approach
We provide simple and accurate analytical expressions for the Regge poles of the Schwarzschild black hole. This is achieved by using third-order WKB approximations to solve the radial wave equations for spins 0, 1 and 2. These results permit us to obtain analytically the dispersion relation and the damping of the "surf...
0906.2601v3
2009-06-30
Cooling a magnetic resonance force microscope via the dynamical back-action of nuclear spins
We analyze the back-action influence of nuclear spins on the motion of the cantilever of a magnetic force resonance microscope. We calculate the contribution of nuclear spins to the damping and frequency shift of the cantilever. We show that, at the Rabi frequency, the energy exchange between the cantilever and the spi...
0906.5420v2
2009-07-03
Magnetic interference patterns in long disordered Josephson junctions
We study a diffusive superconductor - normal metal - superconductor (SNS) junction in an external magnetic field. In the limit of a long junction, we find that the form of the dependence of the Josephson current on the field and on the length of the junction depends on the ratio between the junction width and the lengt...
0907.0632v3
2009-07-12
Symmetries shape the current in ratchets induced by a bi-harmonic force
Equations describing the evolution of particles, solitons, or localized structures, driven by a zero-average, periodic, external force, and invariant under time reversal and a half-period time shift, exhibit a ratchet current when the driving force breaks these symmetries. The bi-harmonic force $f(t)=\epsilon_1\cos(q \...
0907.2029v2
2009-07-21
AFM Dissipation Topography of Soliton Superstructures in Adsorbed Overlayers
In the atomic force microscope, the nanoscale force topography of even complex surface superstructures is extracted by the changing vibration frequency of a scanning tip. An alternative dissipation topography with similar or even better contrast has been demonstrated recently by mapping the (x,y)-dependent tip damping ...
0907.3585v4
2009-07-24
Harmonic damped oscillators with feedback. A Langevin study
We consider a system in direct contact with a thermal reservoir and which, if left unperturbed, is well described by a memory-less equilibrium Langevin equation of the second order in the time coordinate. In such conditions, the strength of the noise fluctuations is set by the damping factor, in accordance with the Flu...
0907.4309v1