We analyze the dynamical evolution of a fluid with nonlinear drag, for which binary collisions are elastic, described at kinetic level by Enskog-Fokker-Planck equation. This model system, rooted in theory Brownian motion, displays really complex behavior when quenched to low temperatures. Its glassy response is controlled long-lived nonequilibrium state, independent degree nonlinearity and also Brownian-Brownian rate. The latter property entails that this persists collisionless case, where...

Abstract In this perspective paper, we look into memory effects in out-of-equilibrium systems. To be concrete, exemplify with the paradigmatic case of granular fluids, although extensions to other contexts such as molecular fluids non-linear drag are also considered. The focus is put on two archetypal effects: Kovacs and Mpemba effects. brief, first related imperfectly reaching a steady state —either equilibrium or non-equilibrium—, whereas second faster despite starting further. Connections...

In this paper we study the existence and linear stability of bright dark breathers in one-dimensional $\mathrm{FPU}$ lattices. On one hand, test range validity a recent proof [G. James, C. R. Acad. Sci., Ser. I: Math, 332, 581 (2001)] using numerical computations. Approximate analytical expressions for small amplitude are found to fit very well exact solutions even far from top phonon band. other numerically large nonpredicted above cited reference. particular, class asymmetric potentials...

Abstract We study the dynamical behaviour of mesoscopic systems in contact with a thermal bath, described either via non-linear Langevin equation at trajectory level —or corresponding Fokker-Planck for probability distribution function ensemble level. Our focus is put on one-dimensional d -dimensional isotropic— confining potentials, detailed balance —fluctuation-dissipation thus holds, and stationary has canonical form bath temperature. When quenching temperature to low enough values,...

A simple lattice model is used to study compaction in granular media. As real experiments, we consider a series of taps separated by large enough waiting times. The relaxation the density exhibits characteristic inverse logarithmic law. Moreover, have been able identify analytically relevant time scale, leading law independent specific values parameters. Also, an expression for asymptotic reached process has derived. theoretical predictions agree fairly well with results from Monte Carlo simulation.

We study four different approximations for finding the profile of discrete solitons in onedimensional Discrete Nonlinear Schrödinger (DNLS) Equation.Three them are (namely, a variational approach, an approximation to homoclinic orbits and Green-function approach), other one is quasi-continuum approximation.All results compared with numerical computations.

We study the zero-temperature limit of one-dimensional Ising model with nearest-neighbor interactions and Glauber dynamics. An exact evolution equation is derived for spin-spin two-time correlation functions following an instantaneous quench from equilibrium at low temperature. In long waiting times correlations become independent distance reduce to autocorrelation function, which exhibits aging, i.e. it decays over a time scale time.

We use soliton perturbation theory and collective coordinate ansatz to investigate the mechanism of ratchets in a driven damped asymmetric double sine-Gordon equation. show that, at second order scheme, internal vibrations can couple {\it effectively}, presence damping, motion center mass, giving rise transport. An analytical expression for mean velocity is derived. The results our analysis confirm mode proposed [Phys. Rev. E {\bf 65} 025602(R) (2002)].

We analyze the linear response properties of uniformly heated granular gas. The intensity stochastic driving fixes value temperature in nonequilibrium steady state reached by system. Here, we investigate two specific situations. First, look into ``direct'' relaxation system after a single (small) jump intensity. This study is carried out different methods. Not only do linearize evolution equations around state, but also derive generalized out-of-equilibrium fluctuation-dissipation relations...

In this paper we study numerically existence and stability of exact dark waves on the (nonintegrable) discrete nonlinear Schrödinger equation for a finite one-dimensional lattice. These are solutions that bifurcate from stationary modes with constant background intensity zero at site, whose initial state translates exactly one site each period internal oscillations. We show characterized by an oscillatory wavelength is closely related velocity. Faster require smaller wavelengths. For slow...

Very recently Willis et al. [Phys. Rev. E 69, 056612 (2004)] have used a collective variable theory to explain the appearance of nonzero energy current in an ac-driven, damped sine-Gordon equation. In this Comment, we prove rigorously that time-averaged ac-driven nonlinear Klein-Gordon system is strictly zero.

Ratchet dynamics of topological solitons the forced and damped discrete double sine-Gordon system are studied. Directed transport occurring both in regular chaotic regions phase space its dependence on damping, amplitude frequency driving, asymmetry parameter, coupling constant, has been extensively investigated. We show that passage from ratchet phase-locked regime to ratchets occurs via a period doubling route chaos that, quite surprisingly, pinned states can exist inside phase-locking for...

This paper proposes a mechanism for soliton ratchets in long Josephson junctions, the absence of external forces and with symmetric field potential. is done by inducing time-dependent phase shift potential sine-Gordon equation. The can also be applied to other similar models.

We study the dynamical behavior of a system with variable number particles n. The empty state n=0 is ground state, while all other states n>0 are degenerate in energy. In equilibrium, mean equal to unity, independently temperature. static properties same as for Backgammon model recently proposed by Ritort [Phys. Rev. Lett. 75, 1190 (1995)], variation kinetics considered. elementary processes arrival and departure particle. rate process constant, obtained from detailed balance condition....

In this paper, interstitial migration generated by scattering with a mobile breather is investigated numerically in Frenkel-Kontorova one-dimensional lattice. Consistent experimental results it shown that diffusion more likely and faster than vacancy diffusion. Our simulations support the hypothesis long-range energy transport mechanism involving moving nonlinear vibrational excitations may significantly enhance mobility of point defects crystal

Recent papers that have studied variants of the Peyrard-Bishop model for DNA, taken into account long range interaction due to dipole moments hydrogen bonds between base pairs. In these models helicity double strand is not considered. this paper we performed an analysis influence on properties static and moving breathers in a Klein-Gordon chain with dipole-dipole interaction. It has been found enlarges existence stability breathers, although effect small typical helical structure DNA....