Josephson effect in superfluid atomic Fermi-gases

TL;DR

This paper explores the internal Josephson effect in superfluid atomic Fermi-gases, demonstrating how laser coupling induces Josephson oscillations and asymmetric tunneling effects unique to atomic systems.

Contribution

It introduces a novel atomic analog of the Josephson effect with laser-controlled tunneling, distinct from solid-state superconductivity.

Findings

Laser fields can induce Josephson oscillations in superfluid Fermi gases.

Asymmetric below-gap tunneling effects are achievable with specific laser detunings.

The phenomena have no direct solid-state analog, highlighting unique atomic system behaviors.

Abstract

We consider an analog of the internal Josephson effect in superfluid atomic Fermi-gases. Four different hyperfine states of the atoms are assumed to be trapped and to form two superfluids via the BCS-type pairing. Weshow that Josephson oscillations can be realized by coupling the superfluids with two laser fields. Choosing the laser detunings in a suitable way leads to an asymmetric below-gap tunneling effect for which there exists no analogue in the context of solid-state superconductivity.