Anomalous specific heat jump in a two-component ultracold Fermi gas

Abstract

The thermodynamic functions of a Fermi gas with spin population imbalance are studied in the temperature-asymmetry plane in the BCS limit. The low temperature domain is characterized by anomalous enhancement of the entropy and the specific heat above their values in the unpaired state, decrease of the gap and eventual unpairing phase transition as the temperature is lowered. The unpairing phase transition induces a second jump in the specific heat, which can be measured in calorimetric experiments. While the superfluid is unstable against a supercurrent carrying state, it may sustain a metastable state if cooled adiabatically down from the stable high-temperature domain. In the latter domain the temperature dependence of the gap and related functions is analogous to the predictions of the BCS theory.

4 pages, 3 figures. v2 includes a discussion of instabilities; v3: final version to appear in PRL

References in corpus (9)

• Observation of Phase Separation in a Strongly-Interacting Imbalanced Fermi Gas
• Phase diagram of a cold polarized Fermi gas
• Induced P-wave Superfluidity in Asymmetric Fermi Gases
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• Stability conditions and Fermi surface topologies in a superconductor
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Cited by in corpus (5)

• Cooling and thermometry of atomic Fermi gases
• Mean field thermodynamics of a spin-polarized spherically trapped Fermi gas at unitarity
• Phase diagram of chiral quark matter: Fulde-Ferrell pairing from weak to strong coupling
• BCS-BEC crossovers and unconventional phases in dilute nuclear matter
• A Mean Field Analysis of Pairing in Asymmetric Fermi Systems at Finite Temperature