Spontaneous solitons in the thermal equilibrium of a quasi-1D bose gas

Tomasz Karpiuk, Piotr Deuar, Przemysław Bienias, Emilia Witkowska, Krzysztof Pawłowski, Mariusz Gajda, Kazimierz Rzewski, Mirosław Brewczyk

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35 Scopus citations


We show that solitons occur generically in the thermal equilibrium state of a weakly interacting elongated Bose gas, without the need for external forcing or perturbations. This reveals a major new quality to the experimentally widespread quasicondensate state, usually thought of as primarily phase-fluctuating. Thermal solitons are seen in uniform 1D, trapped 1D, and elongated 3D gases, appearing as shallow solitons at low quasicondensate temperatures, becoming widespread and deep as temperature rises. This behavior can be understood via thermal occupation of the type II excitations in the Lieb-Liniger model of a uniform 1D gas. Furthermore, we find that the quasicondensate phase includes very appreciable density fluctuations while leaving phase fluctuations largely unaltered from the standard picture derived from a density-fluctuation-free treatment.

Original languageEnglish (US)
Article number205302
JournalPhysical Review Letters
Issue number20
StatePublished - Nov 13 2012
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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