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arXiv · 1011.3737

BCS-BEC crossover in a two-dimensional Fermi gas

G. Bertaina·S. Giorgini
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Abstract

We investigate the crossover from Bardeen-Cooper-Schrieffer (BCS) superfluidity to Bose-Einstein condensation (BEC) in a two-dimensional Fermi gas at T=0 using the fixed-node diffusion Monte Carlo method. We calculate the equation of state and the gap parameter as a function of the interaction strength, observing large deviations compared to mean-field predictions. In the BEC regime our results show the important role of dimer-dimer and atom-dimer interaction effects that are completely neglected in the mean-field picture. Results on Tan's contact parameter associated with short-range physics are also reported along the BCS-BEC crossover.

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G. Bertaina, S. Giorgini. 2011-03-21. BCS-BEC crossover in a two-dimensional Fermi gas. https://doi.org/10.1103/physrevlett.106.110403

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