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A: Fachverband Atomphysik

A 9: Ultra-cold atoms, ions and BEC (with Q)

A 9.41: Poster

Montag, 29. Februar 2016, 16:30–19:00, Empore Lichthof

Dimensional Phase Transitions of Bosons in Optical Lattices with Tunable Hopping — •Bernhard Irsigler¹, Denis Morath², Dominik Straßel², Sebastian Eggert², and Axel Pelster² — ¹Physics Department, Freie Universität Berlin, Germany — ²Physics Department and Research Center OPTIMAS, Technische Universität Kaiserslautern, Germany

Here we investigate in detail how the dimensionality affects the critical temperature of Bose-Einstein condensation. Motivated by the recent experiment [1] we consider bosons in an optical lattice, where the hopping along the three spatial dimensions is assumed to be tunable. With this we model all possible continuous transitions between the dimensions D=1,2,3 and determine the respective critical temperatures in the vicinity of pure integer dimensions, which turn out to agree with the Mermin-Wagner theorem. In the homogeneous case the critical temperature vanishes in D=1,2 and therefore also in the dimensional transition 1→2. However in D=3 the critical temperature is finite and vanishes for 3→2 logarithmically and for 3→1 like a power law. For the harmonically trapped case in any dimension D=1,2,3 the critical temperature remains finite.

[1] A. Vogler, R. Labouvie, G. Barontini, S. Eggert, V. Guarrera, and H. Ott, Phys. Rev. Lett. 113, 215301 (2014).