Abstract:Cold Fermi gases are widely studied examples of strongly interacting quantum systems. Examples include collections of atoms, such as $^{40}K$ and $^6Li$, and neutron matter. In the unitary regime, where the scattering length is very large compared to the mean inter-particle distance, these systems are nonperturbative and exhibit universal behavior. Moreover, they can be created in the lab, providing an excellent testing ground for theoretical approaches to strongly interacting quantum systems. In this talk I will describe quantum Monte Carlo calculations we have been performing to study the signatures of pairing correlations and the superfluid phase transition in finite-size systems. Using the auxiliary-field Monte Carlo method, we study the pairing gap, condensate fraction, pair wavefunction and density profile as a function of temperature. In particular, we discuss the question of whether pairing correlations survive above the condensation temperature in the unitary regime.

Vita:

Chris Gilbreth is a graduate student in the physics department at
Yale University in New Haven, CT. He studies strongly-interacting
finite-size quantum systems, and in particular cold Fermi gases and
chaotic many-particle systems, under the direction of Yoram Alhassid.
He received his M.S. and M.Phil in 2010 and plans on completing his
Ph.D. next year.