Date:2011-9-16, 3:00pm

Venue:Conference Hall 322, Science Building

Title: Two-body scattering in a unitary gas: anomalous phase shifts and dimers

Speaker: Junliang Song

Institute of Quantum Optics and Quantum Information of Austrian Academy of Sciences, Innsbruck, Austria

Abstract:Few-body scattering plays an important role in the low energy properties of quantum gases. In a many-body system, two-body scattering properties can be significantly modified by the medium. We show that in a unitary gas of Fermi-Fermi mixtures, anomalous scattering phase shifts and quasi-dimers with negative masses can appear, as a result of Pauli blocking. We also apply these results to study the lifetime of quasi-particles and dimers at resonances.