Squeezed field path integral description of second sound in Bose-Einstein condensates

Abstract

We propose a generalization of the Feynman path integral using squeezed coherent states. We apply this approach to the dynamics of Bose-Einstein condensates, which gives an effective low energy description that contains both a coherent field and a squeezing field. We derive the classical trajectory of this action, which constitutes a generalization of the Gross Pitaevskii equation, at linear order. We derive the low energy excitations, which provides a description of second sound in weakly interacting condensates as a squeezing oscillation of the order parameter. This interpretation is also supported by a comparison to a numerical c-field method.

arXiv comment10 pages, 6 figures

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Cited by in corpus (5)

• Collective modes and superfluidity of a two-dimensional ultracold Bose gas
• Sound propagation in a two-dimensional Bose gas across the superfluid transition
• First and second sound in a dilute Bose gas across the BKT transition
• Path Integral for Spin-1 Chain in the Fluctuating Matrix Product State Basis
• First and second sound in a compressible 3D Bose fluid