Related papers: The Anti-FPU Problem
Periodic forcing of an oscillatory system produces frequency locking bands within which the system frequency is rationally related to the forcing frequency. We study extended oscillatory systems that respond to uniform periodic forcing at…
We investigate anomalous energy transport processes in the Fermi-Pasta-Ulam $\beta$ lattice. They are determined by the maximum sound velocity of the relevant weakly damped energy carriers. That velocity can be numerically resolved by…
We derive the frequency spectrum of the lowest compressional oscillations of a 3D harmonically trapped Fermi superfluid in the presence of a vortex lattice, treated in the diffused vorticity approximation within a hydrodynamic approach. We…
We study the time scale T to equipartition in a 1D lattice of N masses coupled by quartic nonlinear (hard) springs (the Fermi-Pasta-Ulam beta model). We take the initial energy to be either in a single mode gamma or in a package of low…
We study the evolution of the energy gap in a unitary Fermi gas as a function of temperature. To this end we approximate the Fermi gas by the Hubbard lattice Hamiltonian and solve using the dynamical mean-field approximation. We have found…
Violation of (semi)-detailed balance conditions in lattice gas automata gives rise to unstable spatial fluctuations that lead to phase separation and pattern formation in spinodal decomposition, unstable propagating modes, driven diffusive…
Discrete breathers are ubiquitous structures in nonlinear anharmonic models ranging from the prototypical example of the Fermi-Pasta-Ulam model to Klein-Gordon nonlinear lattices, among many others. We propose a general criterion for the…
In the present paper the resonances of vibrational modes in one-dimensional random Morse lattice are found and analyzed. The resonance energy exchange is observed at some values of elongation. Resonance $2 \omega_1 = \omega_2$ is…
We study dynamics of a phase boundary in a one-dimensional lattice gas, which is initially put into a non-equilibrium configuration and then is let to evolve in time by particles performing nearest-neighbor random walks constrained by…
We consider the original $\beta$-Fermi-Pasta-Ulam-Tsingou ($\beta$-FPUT) system; numerical simulations and theoretical arguments suggest that, for a finite number of masses, a statistical equilibrium state is reached independently of the…
The paper deals with the problem of open systems out of equilibrium. An analytical expression for time-dependent density matrix of two arbitrary coupled identical quantum oscillators interacting with separate reservoirs is derived using…
By analyzing vortex lattices, re-entrant Cooper pairing and Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states in a single theoretical framework we explore how vortices and spin textures join to protect superconductivity against large magnetic…
The Luttinger liquid model, which describes interacting electrons in a single-channel quantum wire, is completely integrable in the absence of disorder and as such does not exhibit any relaxation to equilibrium. We consider relaxation…
A system consisting of the cubic complex Ginzburg-Landau equation which is linearly coupled to an additional linear dissipative equation, is considered. The model was introduced earlier in the context of dual-core nonlinear optical fibers…
We experimentally investigate the stability of a quantum gas with repulsive interactions in an optical 1D lattice subjected to periodic driving. Excitations of the gas in the lowest lattice band are analyzed across the complete stability…
Recent experiments have revitalized the interest in a Fermi gas of ultracold atoms with strong repulsive interactions. In spite of its seeming simplicity, this system exhibits a complex behavior, resulting from the competing action of two…
The study of non-linear oscillator chains in classical many-body dynamics has a storied history going back to the seminal work of Fermi, Pasta, Ulam and Tsingou (FPUT). We introduce a new family of such systems which consist of chains of…
Finding equilibration times is a major unsolved problem in physics with few analytical results. Here we look at equilibration times for quantum gases of bosons and fermions in the regime of negligibly weak interactions, a setting which not…
Equilibrium and non-equilibrium relaxation behaviors of two-dimensional superconducting arrays are investigated via numerical simulations at low temperatures in the presence of incommensurate transverse magnetic fields, with frustration…
The frequency of the breathing mode of a classical two dimensional Fermi gas in a harmonic confinement is fixed by the scale invariance of the Hamiltonian. Scale invariance is broken on the quantum mechanical level by introducing the two…