Schedule Aug 24, 2012
Spontaneous Solitons in the Thermal Equilibrium of a Quasi-one-dimensional Bose Gas
Piotr Deuar, Emilia Witkowska, Mariusz Gajda, Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland , Tomasz Karpiuk, Miroslaw Brewczyk , Wydzia?u Fizyki, Uniwersytet w Bia?ymstoku, ul. Lipowa 41, PL-15-424 Bia?ystok, Poland , Przemys?aw Bienias, Krzysztof Paw?owski, Kazimierz Rz??ewski, Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland, ,

Solitons in ultra-cold gases were first observed to be generated by phase-imprinting [1]. More recently, their spontaneous formation in 1D gases was predicted as a result of bringing the cloud out of equilibrium via the Kibble-Zurek mechanism [2] or quantum quenches [3]. We find that they actually occur generically in the thermal equilibrium state of a weakly-interacting elongated Bose gas, without the need for external forcing or perturbations [4]. This can be understood via thermal occupation of the famous and somewhat elusive Type II excitations in the Lieb-Liniger model of a uniform 1D gas.

[1] S. Burger et al., Phys. Rev. Lett. 83, 5198 (1999); J. Denschlag et al., Science 287, 97 (2000).
[2] W. H. Zurek, Phys. Rev. Lett. 102, 105702 (2009); B. Damski and W. H. Zurek, Phys. Rev. Lett. 104, 160404 (2010); E. Witkowska, et al., Phys. Rev. Lett. 106, 135301 (2011).
[3] M. Schmidt et al., arXiv:1203.3651 (2012).
[4] T. Karpiuk et al., arXiv:1205.2363 (2012).

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