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Updated: Jan 8, 2026

Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Shapiro steps in strongly-interacting Fermi gases
Giulia Del Pace1,2,3, Diego Hernández-Rajkov2,3, Vijay Pal Singh4
1Department of Physics, University of Florence, Sesto Fiorentino, Italy.
Researchers observed Shapiro steps in driven Josephson junctions of ultracold atoms. This finding reveals synchronization mechanisms in quantum many-body systems and opens new avenues for studying nonequilibrium dynamics.
Area of Science:
- Quantum physics
- Ultracold atoms
- Condensed matter physics
Background:
- Driven many-body systems exhibit complex dynamics.
- Josephson junctions are crucial for quantum electronics.
- Ultracold atoms provide a platform for simulating quantum phenomena.
Purpose of the Study:
- To observe Shapiro steps in Josephson junctions of Fermi superfluids.
- To investigate the underlying synchronization mechanisms.
- To explore emergent nonequilibrium dynamics in driven quantum systems.
Main Methods:
- Experimental realization of Josephson junctions with ultracold Fermi superfluids.
- Periodic driving of the system.
- Measurement of current-potential characteristics.
- Direct measurement of the current-phase relationship.
- Detection of phase-slippage processes.
- Circuital modeling and numerical simulations.
Main Results:
- Observation of quantized plateaus (Shapiro steps) in current-potential characteristics.
- Plateau height and width correlate with drive frequency and junction nonlinearity.
- Demonstration of synchronization between relative phase and external drive.
- Detection of vortex-antivortex pairs indicating phase slippage.
Conclusions:
- Shapiro steps arise from a synchronization mechanism in driven Josephson junctions.
- The study provides insights into emergent nonequilibrium dynamics.
- This work opens prospects for simulating and understanding driven quantum many-body systems.
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