Josephson current flowing through a nontrivial geometry: Role of pairing fluctuations across the BCS-BEC crossover
Year: 2023
Authors: Piselli V., Pisani L., Strinati GC.
Autors Affiliation: Univ Camerino, Sch Sci & Technol, Phys Div, I-62032 Camerino, MC, Italy; Ist Nazl Ottica, CNR, Sede Firenze, I-50125 Florence, FI, Italy.
Abstract: A realistic description of the Josephson effect at finite temperature with ultracold Fermi gases embedded in nontrivial geometrical constraints (typically, a trap plus a barrier) requires appropriate consideration of pairing fluctuations that arise in inhomogeneous environments. Here, we apply the theoretical approach developed in a companion paper [Pisani et al., Phys. Rev. B 108, 214503 (2023)], where the inclusion of pairing fluctuations beyond mean field across the BCS-Bose-Einstein-condensate (BEC) crossover at finite temperature is combined with a detailed description of the gap parameter in a nontrivial geometry. In this way, we are able to account for the experimental results on the Josephson critical current, reported both at low temperature for various couplings across the BCS-BEC crossover and as a function of temperature at unitarity. Besides validating the theoretical approach of the companion paper, our numerical results reveal generic features of the Josephson effect which may not readily emerge from an analysis of corresponding experiments with condensed-matter samples owing to the unique intrinsic flexibility of experiments with ultracold gases.
Journal/Review: PHYSICAL REVIEW B
Volume: 108 (21) Pages from: 214504-1 to: 214504-8
KeyWords: Energy-spectrum; GasDOI: 10.1103/PhysRevB.108.214504Citations: 2data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-09-15References taken from IsiWeb of Knowledge: (subscribers only)