Interactions in a dilute fermi gas

D. H. Santamore, Eddy Timmermans

Scott B. Papp, Brian DeMarco, Deborah Jin

John E. Thomas

Sergei V. Traven

It is demonstrated that the interaction between fluctuations of the pairing field in a two-dimensional (2D) dilute attractive Fermi gas stabilizes the low-temperature phase of the system. This result, which is valid for all values of the "coupling parameter" $\frac{{\ensuremath{\varepsilon}}_{0}}{{\ensuremath{\varepsilon}}_{F}}$ (where ${\ensuremath{\varepsilon}}_{0}$ is the two-fermion binding energy and ${\ensuremath{\varepsilon}}_{F}$ is the Fermi energy), then allows one to conclude that a 2D dilute attractive Fermi gas is superfluid at small but finite temperature.

Soon Yong Chang, Mohit Randeria, Nandini Trivedi

Лев П. Питаевский, S. Stringari

Abstract This is the first of a series of chapters devoted to interacting Fermi gases, with special focus here on the effects of superfluidity. It starts with a brief discussion of the ideal Fermi gas and then focuses on the properties of dilute interacting Fermi gases. Topics include the weakly repulsive Fermi gas; the gas of composite bosons; the BCS limit of a weakly interacting Fermi gas; the strongly interacting, but still dilute, unitary Fermi gas where the scattering length is much larger than the average interatomic distance; the BCS–BEC crossover; and the Bogoliubov–de Gennes approach. A discussion of the main physical quantities predicted by mean-field theory and by quantum Monte Carlo simulations, including, in particular, the equation of state, the momentum distribution, and the condensation of pairs, is also presented.