BCS-BEC Crossover in a Two-Dimensional Fermi Gas

Journal Article · Fri Mar 18 00:00:00 EDT 2011 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.106.110403· OSTI ID:21562094

Bertaina, G ^[1]; Giorgini, S ^[2]

---

1. Institute of Theoretical Physics, Ecole Polytechnique Federale de Lausanne EPFL, CH-1015 Lausanne (Switzerland); INO-CNR BEC Center and Dipartimento di Fisica, Universita di Trento, 38123 Povo (Italy)
2. INO-CNR BEC Center and Dipartimento di Fisica, Universita di Trento, 38123 Povo (Italy)

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.

• OSTI ID: 21562094
• Journal Information: Physical Review Letters, Vol. 106, Issue 11; Other Information: DOI: 10.1103/PhysRevLett.106.110403; (c) 2011 American Institute of Physics; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BCS THEORY
BOSE-EINSTEIN CONDENSATION
DIFFUSION
DIMERS
EQUATIONS OF STATE
FERMI GAS
INTERACTIONS
MEAN-FIELD THEORY
MONTE CARLO METHOD
SUPERFLUIDITY
TANTALUM NITRIDES
TWO-DIMENSIONAL CALCULATIONS
CALCULATION METHODS
EQUATIONS
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
REFRACTORY METAL COMPOUNDS
TANTALUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS