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Josephson effect throughout the BCS-BEC crossover
A Spuntarelli1, P Pieri, G C Strinati
1Dipartimento di Fisica, Università di Camerino, I-62032 Camerino, Italy.
Physical Review Letters
|August 7, 2007
Summary
We investigated the Josephson effect in neutral fermions near the BEC-BCS crossover. The Josephson current is enhanced at unitarity, approaching Landau limits determined by excitations.
Area of Science:
- Condensed matter physics
- Quantum mechanics
Background:
- The study focuses on the stationary Josephson effect in neutral fermions.
- It examines the behavior across the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover.
Purpose of the Study:
- To numerically solve the Bogoliubov-de Gennes equations at zero temperature.
- To analyze the Josephson current and critical current behavior.
Main Methods:
- Numerical solution of Bogoliubov-de Gennes equations.
- Zero-temperature analysis.
Main Results:
- Josephson current is enhanced for all barriers near unitarity.
- Critical current approaches Landau limiting values, influenced by pair-breaking or sound-mode excitations.
- A method is proposed to extract the pairing gap from Landau limiting current.
Conclusions:
- The BCS-BEC crossover significantly impacts the Josephson effect.
- Understanding these excitations is key to predicting critical current behavior.
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