42 research outputs found
Metropolis-Hastings thermal state sampling for numerical simulations of Bose-Einstein condensates
We demonstrate the application of the Metropolis-Hastings algorithm to
sampling of classical thermal states of one-dimensional Bose-Einstein
quasicondensates in the classical fields approximation, both in untrapped and
harmonically trapped case. The presented algorithm can be easily generalized to
higher dimensions and arbitrary trap geometry. For truncated Wigner simulations
the quantum noise can be added with conventional methods (half a quantum of
energy in every mode). The advantage of the presented method over the usual
analytical and stochastic ones lies in its ability to sample not only from
canonical and grand canonical distributions, but also from the generalized
Gibbs ensemble, which can help to shed new light on thermodynamics of
integrable systems.Comment: 13 pages, 4 figure
Degenerate Bose gases with uniform loss
We theoretically investigate a weakly-interacting degenerate Bose gas coupled
to an empty Markovian bath. We show that in the universal phononic limit the
system evolves towards an asymptotic state where an emergent temperature is set
by the quantum noise of the outcoupling process. For situations typically
encountered in experiments, this mechanism leads to significant cooling. Such
dissipative cooling supplements conventional evaporative cooling and dominates
in settings where thermalization is highly suppressed, such as in a
one-dimensional quasicondensate.Comment: 9 pages, 5 figures, open access publicatio