Spin-dipole mode in a trapped Fermi gas near unitarity

Year: 2020

Authors: Tajima H., Recati A., Ohashi Y.

Autors Affiliation: RIKEN, Quantum Hadron Phys Lab, Nishina Ctr RNC, Wako, Saitama 3510198, Japan;‎ Univ Trento, INO CNR BEC Ctr, I-38123 Povo, Italy;‎ Univ Trento, Dipartimento Fis, I-38123 Povo, Italy;‎ Ist Nazl Fis Nucl, Trento Inst Fundamental Phys & Applicat, I-38123 Trento, Italy; Keio Univ, Dept Phys, Kohoku Ku, Yokohama, Kanagawa 2238522, Japan

Abstract: We theoretically investigate the spin-dipole oscillation of a strongly interacting Fermi gas confined by a harmonic trapping potential. By using a diagrammatic strong-coupling theory combined with a local density approximation and a sum rule approach, we study the temperature dependence of the spin-dipole frequency near unitarity. The connection of the spin-dipole frequency with the spin susceptibility and the pairing correlations is exploited. While the spin-dipole frequency exactly coincides with the trap frequency in a noninteracting Fermi gas, it is shown to be strongly enhanced in the superfluid state, because of the suppression of the spin degree of freedom due to the spin-singlet Cooper-pair formation. In strongly interacting Fermi gases, such enhancement occurs even above the superfluid phase transition temperature, due to the strong pairing correlations.


Volume: 101 (1)      Pages from: 013610-1  to: 013610-7

More Information: H.T. thanks K. Iida, F. Scazza, R. Hanai, M. Pini, and M. Ota for useful discussions. This work was supported by a Grant-in-Aid for JSPS fellows (Grant No. 17J03975). A.R. acknowledges support from the Provincia Autonoma di Trento and the FISh project of the National Institute for Nuclear Physics. Y.O. was supported by a Grant-in-Aid for Scientific Research from MEXT and JSPS in Japan (Grants No. JP18K11345, No. JP18H05406, and No. JP19K03689).
DOI: 10.1103/PhysRevA.101.013610

Citations: 2
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