Magnetic properties and strong-coupling corrections in an ultracold Fermi gas with population imbalance

Abstract

We investigate magnetic properties of an ultracold Fermi gas with population imbalance. In the presence of population imbalance, the strong-coupling theory developed by Nozieres and Schmitt-Rink (which is frequently referred to as the NSR theory, or Gaussian fluctuation theory) is known to give unphysical results in the BCS-BEC crossover region. We point out that this problem comes from how to treat pseudogap effects originating from pairing fluctuations and many-body corrections to the spin susceptibility. We also clarify how to overcome this problem by including higher order fluctuations beyond the ordinary T-matrix theory. Calculated spin susceptibility based on our extended T-matrix theory agrees well with the recent experiment on a 6Li Fermi gas.

7 pages, 4 figures, Proceedings of QFS 2012

References in corpus (6)

• Many-Body Physics with Ultracold Gases
• Theory of ultracold Fermi gases
• BEC-BCS crossover, phase transitions and phase separation in polarized resonantly-paired superfluids
• Single-particle properties and pseudogap effects in the BCS-BEC crossover regime of an ultracold Fermi gas above Tc
• Speckle Imaging of Spin Fluctuations in a Strongly Interacting Fermi Gas
• BCS-BEC crossover in an asymmetric two-component Fermi gas

Cited by in corpus (5)

• The BCS-BEC crossover: From ultra-cold Fermi gases to nuclear systems
• Polarized Fermi gases at finite temperature in the BCS-BEC crossover
• Bose-Fermi Pairs in a Mixture and the Luttinger Theorem within a Nozieres-Schmitt-Rink like Approach
• Occupation numbers in strongly polarized Fermi gases and the Luttinger theorem
• Luttinger theorem and imbalanced Fermi systems