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.

BCS-BEC crossover in a two-dimensional Fermi gas / Bertaina, G; Giorgini, S. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 106:11(2011), p. 110403. [10.1103/PhysRevLett.106.110403]

BCS-BEC crossover in a two-dimensional Fermi gas

Bertaina, G;
2011

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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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11696/60885
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