Application of the functional renormalization group to Bose gases: From linear to hydrodynamic fluctuations

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Abstract

We study weakly interacting Bose gases using the functional renormalization group with a hydrodynamic effective action. We use a scale-dependent parametrization of the boson fields that interpolates between a Cartesian representation at high momenta and an amplitude-phase one for low momenta. We apply this to Bose gases in two and three dimensions near the superfluid phase transition where they can be described by statistical O(2) models. We are able to give consistent physical descriptions of the infrared regime in both two and three dimensions. In particular, and in contrast to previous studies using the functional renormalization group, we find a stable superfluid phase at finite temperatures in two dimensions. We compare our results for the superfluid and boson densities with Monte-Carlo simulations, and we find they are in reasonable agreement.

Bibliographical metadata

Original languageEnglish
Article number144502
JournalPhysical Review B
Volume98
Issue number14
Early online date1 Oct 2018
DOIs
Publication statusPublished - 1 Oct 2018

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