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Critical Point of an Interacting Two-Dimensional Atomic Bose Gas

Peter Krüger·Zoran Hadzibabic·Jean Dalibard
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Abstract

We have measured the critical atom number in an array of harmonically trapped two-dimensional (2D) Bose gases of rubidium atoms at different temperatures. We found this number to be about five times higher than predicted by the semi-classical theory of Bose-Einstein condensation (BEC) in the ideal gas. This demonstrates that the conventional BEC picture is inapplicable in an interacting 2D atomic gas, in sharp contrast to the three-dimensional case. A simple heuristic model based on the Berezinskii-Kosterlitz-Thouless theory of 2D superfluidity and the local density approximation accounts well for our experimental results.

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Peter Krüger, Zoran Hadzibabic, Jean Dalibard. 2007-12-11. Critical Point of an Interacting Two-Dimensional Atomic Bose Gas. https://doi.org/10.1103/physrevlett.99.040402

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