Heidelberg 2015 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

Q: Fachverband Quantenoptik und Photonik

Q 15: Poster: Quantum Optics and Photonics I

Q 15.33: Poster

Monday, March 23, 2015, 17:00–19:00, C/Foyer

Quasi-Condensation and Superfluidity in a Ring Trap — Hansjörg Polster and •Carsten Henkel — University of Potsdam, Germany

Low-dimensional Bose gases suffer from large phase fluctuations that prevent the formation of a proper condensate as defined by Penrose and Onsager. We study a one-dimensional, phase-fluctuating gas in the cross-over region between the ideal gas and the quasi-condensate (weak interactions). Correlation functions of any order are found by mapping the quantum field theory to a random walk in the complex plane, making a classical field approximation [1]. We discuss in particular full distribution functions for the atomic density, including the formation of pairs and clusters at the onset of quasi-condensation. Currently we investigate the distribution function of the total particle current in a rotating ring trap [2] which provides insight into the superfluid behaviour of the gas.

[1] L. W. Gruenberg and L. Gunther, Phys. Lett. A 38 (1972) 463; D. J. Scalapino, M. Sears, and R. A. Ferrell, Phys. Rev. B 6 (1972) 3409

[2] I. Carusotto and Y. Castin, C. R. Physique 5 (2004) 107