X iv : c on d - m at / 9 70 50 47 v 1 6 M ay 1 99 7 Far From Equilibrium Dynamics of the Bose Gas

ar X iv : c on d - m at / 9 70 50 47 06 M ay 1 99 7 Far From Equilibrium Dynamics of the Bose Gas

ar X iv : c on d - m at / 9 51 10 58 v 2 2 8 M ar 1 99 6 Phase ordering kinetics of the Bose gas

We study the approach to equilibrium of a Bose gas to a superfluid state. We point out that dynamic scaling, characteristic of far from equilibrium phaseordering systems, should hold. We stress the importance of a non-dissipative Josephson precession term in driving the system to a new universality class. A model of coarsening in dimension d = 2, involving a quench between two temperatures belo...

ar X iv : p at t - so l / 9 50 50 05 v 1 2 6 M ay 1 99 5 Domain Coarsening in Systems Far from Equilibrium

The growth of domains of stripes evolving from random initial conditions is studied in numerical simulations of models of systems far from equilibrium such as Rayleigh-Benard convection. The size of the domains deduced from the inverse width of the Fourier spectrum is found to scale as t 1/5 for both potential and nonpotential models. The morphology of the domains and the defect structures are ...

ar X iv : c on d - m at / 9 70 52 40 v 1 2 3 M ay 1 99 7 Collective and single particle excitations of a trapped Bose gas

The density of states of a Bose-condensed gas confined in a harmonic trap is investigated. The predictions of Bogoliubov theory are compared with the ones of Hartree-Fock theory and of the hydrodynamic model. We show that the Hartree-Fock scheme provides an excellent description of the excitation spectrum in a wide range of energy, revealing a major role played by single-particle excitations in...

ar X iv : c on d - m at / 9 60 51 19 v 1 2 0 M ay 1 99 6 Dynamics of Collapse of a Confined Bose Gas

Rigorous results on the nonlinear dynamics of a dilute Bose gas with a negative scattering length in an harmonic magnetic trap are presented and sufficient conditions for the collapse of the system are formulated. By using the virial theorem for the Gross-Pitaevskii equation in an external field we analyze the temporal evolution of the mean square radius I = r 2 | ψ | 2 dV of the gas cloud. In ...