We address the physics of equilibration in ultracold atomic gases following a quench of the interaction parameter. Our work is based on a bath model which generates damping of the bosonic excitations. We illustrate this dissipative behavior through the momentum distribution of the excitations ${n}_{k}$ , observing that larger $k$ modes have shorter relaxation times $\ensuremath{\tau}(k)$; they will equilibrate faster, as has been claimed in recent experimental work. We identify three time regimes. At short times ${n}_{k}$ exhibits oscillations; these are damped out at intermediate times where the system appears to be in a false or slowly converging equilibrium. Finally, at longer times, full equilibration occurs. This false equilibrium is, importantly, associated with the $k$ dependence in $\ensuremath{\tau}(k)$ and has implications for experiment.We address the physics of equilibration in ultracold atomic gases following a quench of the interaction parameter. Our work is based on a bath model which generates damping of the bosonic excitations. We illustrate this dissipative behavior through the momentum distribution of the excitations ${n}_{k}$, observing that larger $k$ modes have shorter relaxation times $\ensuremath{\tau}(k)$; they will equilibrate faster, as has been claimed in recent experimental work. We identify three time regimes. At short times ${n}_{k}$ exhibits oscillations; these are damped out at intermediate times where the system appears to be in a false or slowly converging equilibrium. Finally, at longer times, full equilibration occurs. This false equilibrium is, importantly, associated with the $k$ dependence in $\ensuremath{\tau}(k)$ and has implications for experiment.

arXiv:1403.0141Physical Review AAug 14, 201432 citations

{n}_{k}

, observing that larger

k

modes have shorter relaxation times $\ensuremath{\tau}(k)$; they will equilibrate faster, as has been claimed in recent experimental work. We identify three time regimes. At short times

{n}_{k}

exhibits oscillations; these are damped out at intermediate times where the system appears to be in a false or slowly converging equilibrium. Finally, at longer times, full equilibration occurs. This false equilibrium is, importantly, associated with the

k

dependence in $\ensuremath{\tau}(k)$ and has implications for experiment.