The induced interaction among the majority spin species, due to the presence of the minority species, is computed for the case of a population-imbalanced resonantly interacting Fermi gas. It is shown that this interaction leads to an instability, at low temperatures, of the recently observed polaron Fermi liquid phase of strongly imbalanced Fermi gases to a $p$ -wave superfluid state. We find that the associated transition temperature, while quite small in the weakly interacting BCS regime, is experimentally accessible in the strongly interacting unitary regime.The induced interaction among the majority spin species, due to the presence of the minority species, is computed for the case of a population-imbalanced resonantly interacting Fermi gas. It is shown that this interaction leads to an instability, at low temperatures, of the recently observed polaron Fermi liquid phase of strongly imbalanced Fermi gases to a $p$-wave superfluid state. We find that the associated transition temperature, while quite small in the weakly interacting BCS regime, is experimentally accessible in the strongly interacting unitary regime.

arXiv:1011.4536Physical Review AMay 31, 201117 citations

Thermodynamics of Spin-Imbalanced Fermi Gases with S U ( N ) -Symmetric Interaction

Chengdong He, Xin-Yuan Gao, Ka Kwan Pak +6 more

Thermodynamics of degenerate Fermi gases has been extensively studied through various aspects such as Pauli blocking effects, collective modes, BCS superfluidity, and more. Despite this, multicomponent fermions with imbalanced spin configurations remain largely unexplored, particularly beyond the two-component scenario. In this Letter, we generalize the thermodynamic study of SU(N) fermions to spin-imbalanced configurations based on density fluctuations. Theoretically, we provide closed-form expressions of density fluctuation across all temperature ranges for general spin population setups. Experimentally, after calibrating the measurements with deeply degenerate ^{173}Yb Fermi gases under spin-balanced configurations (N≤6), we examine the density fluctuations in spin-imbalanced systems. Specifically, we investigate two-species and four-species configurations to validate our theoretical predictions. Our analysis indicates that interaction enhancement effects can be significant even in highly spin-imbalanced systems. Finally, as an application, we use this approach to examine the decoherence process. Our Letter provides a deeper understanding of the thermodynamic features of spin-imbalanced multicomponent Fermi gases and opens new avenues for exploring complex quantum many-body systems.Thermodynamics of degenerate Fermi gases has been extensively studied through various aspects such as Pauli blocking effects, collective modes, BCS superfluidity, and more. Despite this, multicomponent fermions with imbalanced spin configurations remain largely unexplored, particularly beyond the two-component scenario. In this Letter, we generalize the thermodynamic study of SU(N) fermions to spin-imbalanced configurations based on density fluctuations. Theoretically, we provide closed-form expressions of density fluctuation across all temperature ranges for general spin population setups. Experimentally, after calibrating the measurements with deeply degenerate ^{173}Yb Fermi gases under spin-balanced configurations (N≤6), we examine the density fluctuations in spin-imbalanced systems. Specifically, we investigate two-species and four-species configurations to validate our theoretical predictions. Our analysis indicates that interaction enhancement effects can be significant even in highly spin-imbalanced systems. Finally, as an application, we use this approach to examine the decoherence process. Our Letter provides a deeper understanding of the thermodynamic features of spin-imbalanced multicomponent Fermi gases and opens new avenues for exploring complex quantum many-body systems.

arXiv:2409.04960Physical Review LettersMay 7, 20253 citations

Ultracold Fermi Gases: Towards BCS

Gora V. Shlyapnikov

International Conference on Atomic Physics (ICAP)Apr 1, 20031 citation

p

-wave superfluid state. We find that the associated transition temperature, while quite small in the weakly interacting BCS regime, is experimentally accessible in the strongly interacting unitary regime.