Scientific Results

Josephson effect with superfluid fermions in the two-dimensional BCS-BEC crossover

Year: 2020

Authors: Salasnich L., Pascucci F.

Autors Affiliation: 1Dipartimento di Fisica e Astronomia “Galileo Galilei,” Università di Padova, via Marzolo 8, 35131 Padova, Italy; Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche, CNR-INO, via Nello Carrara 2, 50019 Sesto Fiorentino, Italy

Abstract: We investigate the macroscopic quantum tunneling of fermionic superfluids in the two-dimensional BCS-BEC crossover by using an effective tunneling energy which explicitly depends on the condensate fraction and the chemical potential of the system. We compare the mean-field effective tunneling energy with the beyond-mean -field one, finding that the mean-field tunneling energy is not reliable in the BEC regime of the crossover. Then we solve the Josephson equations of the population imbalance and the relative phase, calculating the frequency of tunneling oscillation both in the linear regime and in the nonlinear one. Our results show that the Josephson frequency is higher in the intermediate regime of the BCS-BEC crossover due to the peculiar behavior of the effective tunneling energy in the crossover.

Journal/Review: PHYSICAL REVIEW A

Volume: 102      Pages from: 013325-1  to: 013325-7

KeyWords: BCS-BEC crossover; 2D Josephson effect; condensate fraction
DOI: 10.1103/PhysRevA.102.013325

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