Reliable equation of state for composite bosons in the 2D BCS-BEC crossover

Abstract

We briefly discuss recent experiments on the BCS-BEC crossover with ultracold alkali-metal atoms both in three-dimensional configurations and two-dimensional ones. Then we analyze the quantum-field-theory formalism used to describe an attractive $D$-dimensional Fermi gas taking into account Gaussian fluctuations. Finally, we apply this formalism to obtain a reliable equation of state of the 2D system at low temperaratures in the BEC regime of the crossover by performing a meaningful dimensional regularization of the divergent zero-point energy of collective bosonic excitations.

arXiv comment4 pages, 2 figures, presented to the Conference SUPERSTRIPES 2015, June 13-18, 2015 (Ischia, Italy), Proceedings to be published in the Journal of Superconductivity and Novel Magnetism