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Quantum Monte Carlo study of a one-dimensional phase-fluctuating condensate

C. Gils·L. Pollet·A. Vernier·F. Hebert·G. G. Batrouni·M. Troyer
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Abstract

We study numerically the low temperature behavior of a one-dimensional Bose gas trapped in an optical lattice. For a sufficient number of particles and weak repulsive interactions, we find a clear regime of temperatures where density fluctuations are negligible but phase fluctuations are considerable, i.e., a quasicondensate. In the weakly interacting limit, our results are in very good agreement with those obtained using a mean-field approximation. In coupling regimes beyond the validity of mean-field approaches, a phase-fluctuating condensate also appears, but the phase-correlation properties are qualitatively different. It is shown that quantum depletion plays an important role.

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C. Gils, L. Pollet, A. Vernier, F. Hebert, G. G. Batrouni, M. Troyer. 2007-07-04. Quantum Monte Carlo study of a one-dimensional phase-fluctuating condensate. https://doi.org/10.1103/physreva.75.063631

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