Macroscopic Periodic Tunneling of Fermi Atoms in the BCS-BEC Crossover

TL;DR

This paper investigates macroscopic quantum tunneling in fermionic superfluids across the BCS-BEC crossover, deriving Josephson equations and analyzing oscillation modes in ^40K atoms.

Contribution

It introduces a theoretical framework for atomic Josephson junctions in fermionic superfluids and explores oscillation modes during the BCS-BEC crossover.

Findings

Derived atomic Josephson junction equations for fermionic superfluids.

Calculated oscillation frequencies depending on tunneling and sound velocity.

Analyzed the BCS-BEC crossover in ^40K superfluids.

Abstract

We study the macroscopic quantum tunneling of two weakly-linked superfluids made of interacting fermionic atoms. We derive atomic Josephson junction equations and find that zero-mode and pi-mode frequencies of coherent atomic oscillations depend on the tunneling coefficient and the sound velocity of the superfluid. By considering a superfluid of ^40K atoms, we calculate these oscillation frequencies in the crossover from the Bardeen-Cooper-Schrieffer state of weakly-bound Cooper pairs to the Bose-Einstein Condensate of strongly-bound molecular dimers.