Dimensionally Induced Phase Transition of the Weakly Interacting Ultracold Bose Gas

Abstract

We investigate the dimensionally induced phase transition from the normal to the Bose-Einstein-condensed phase for a weakly interacting Bose gas in an optical lattice. To this end we make use of the Hartree-Fock-Bogoliubov-Popov theory, where we include numerically exact hopping energies and effective interaction strengths. At first we determine the critical chemical potential, where we find a much better agreement with recent experimental data than a pure Hartree-Fock treatment. This finding is in agreement with the dominant role of quantum fluctuations in lower dimensions, as they are explicitly included in our theory. Furthermore, we determine for the 1D-3D-transition the power-law exponent of the critical temperature for two different non-interacting Bose gas models yielding the same value of 1/2, which indicates that they belong to the same universality class. For the weakly interacting Bose gas we find for both models that this exponent is robust with respect to finite interaction strengths.

References in corpus (6)

• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Experimental observation of oscillating and interacting matter wave dark solitons
• Crossover from 2D to 3D in a weakly interacting Fermi gas
• Interacting Bose gases in quasi-one dimensional optical lattices
• Deconfinement in a 2D optical lattice of coupled 1D boson systems
• Cross-dimensional phase transition from an array of 1D Luttinger liquids to a 3D Bose-Einstein condensate

Cited by in corpus (5)

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• Thermodynamics of Trapped Photon Gases at Dimensional Crossover from 2D to 1D
• Photon BEC with Thermo-Optic Interaction at Dimensional Crossover
• Collective modes in multicomponent condensates with anisotropy
• Quantum phase transition of the Bose-Hubbard model on cubic lattice with anisotropic hopping