Effective temperature of a superfluid flowing in a random potential

Taiki Haga; Masahito Ueda

doi:10.1103/physrevresearch.2.043316

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arXiv · 1909.11997

Effective temperature of a superfluid flowing in a random potential

Taiki Haga·Masahito Ueda

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Abstract

The spatial fluctuations of a superfluid flowing in a weak random potential are investigated. We employ classical field theory to demonstrate that the disorder-averaged nonequilibrium second-order correlation of the order parameter at zero temperature is identical to the thermally averaged equilibrium counterpart of a uniform superfluid at an effective temperature. The physics behind this equivalence is that scattering of a moving condensate by disorder has the same effect on the correlation function as equilibrium thermal excitations. The correlation function exhibits an exponential decay in one dimension and a power-law decay in two dimensions. We show that the effective temperature can be measured in an interference experiment of ultracold atomic gases.

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Taiki Haga, Masahito Ueda. 2019-09-26. Effective temperature of a superfluid flowing in a random potential. https://doi.org/10.1103/physrevresearch.2.043316

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