Out-of-equilibrium dynamical properties of Bose-Einstein condensates in a ramped up weak disorder

Rodrigo P. A. Lima; Milan Radonjić; Axel Pelster

doi:10.21468/scipostphys.20.1.010

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arXiv · 2501.01513

Out-of-equilibrium dynamical properties of Bose-Einstein condensates in a ramped up weak disorder

Rodrigo P. A. Lima·Milan Radonjić·Axel Pelster

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Abstract

We theoretically study how the superfluid and condensate deformation of a weakly interacting ultracold Bose gas evolve during the ramp-up of an external weak disorder potential. Both resulting deformations turn out to consist of two distinct contributions, namely a reversible equilibrium one, already predicted by Huang and Meng in 1992, and a nonequilibrium dynamical one, whose magnitude depends on the details of the ramping protocol. For the specific case of the exponential ramp-up protocol, we are able to derive analytical time-dependent expressions for the above quantities. After a sufficiently long time, a steady state emerges that is generically out of equilibrium. We take the first step in investigating its properties by studying its relaxation dynamics. In addition, we analyze the two-time correlation function and elucidate its relation to the equilibrium and the dynamical part of the condensate deformation.

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Rodrigo P. A. Lima, Milan Radonjić, Axel Pelster. 2025-01-02. Out-of-equilibrium dynamical properties of Bose-Einstein condensates in a ramped up weak disorder. https://doi.org/10.21468/scipostphys.20.1.010

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