Josephson Oscillation and Self-Trapping in a Fermi Superfluid Gas across the BCS-BEC Crossover

• Published in: Journal of low temperature physics Vol. 208; no. 5-6; pp. 372 - 378
• Main Authors: Tokimoto, Jun, Tsuchiya, Shunji, Nikuni, Tetsuro
• Format: Journal Article
• Language: English
• Published: New York Springer US 03.08.2022; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Fluids; Low temperature physics; Magnetic Materials; Magnetism; Oscillations; Physics; Physics and Astronomy; Plasma frequencies; Superfluidity; Trapping; Wave functions; Josephson oscillation; BCS-BEC crossover; Quantum gas; Fermi superfluid
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/s10909-022-02794-w

Josephson oscillation is the phenomenon of supercurrent tunneling through a potential barrier separating two superfluids, resulting in the oscillation of the population difference. In the experiment of Bose-condensed gas, with increasing the initial population difference between the two condensate wavefunctions, a transition from the Josephson oscillation to “self-trapping”, in which the population difference oscillates around the nonzero value, has been observed. We study normal Josephson oscillations and self-trapping in a Fermi superfluid gas across the BCS-BEC crossover by numerically solving the time-dependent Bogoliubov-de Gennes equations. We confirm that self-trapping occurs in the whole region across the BCS-BEC crossover. We also discuss detailed behaviors of plasma frequencies and critical values of initial population difference for the transition between normal Josephson oscillations and self-trapping across the BCS-BEC crossover.