Stabilizing an Ultracold Fermi Gas against Fermi Acceleration to Superdiffusion through Localization

Area of Science:

• Quantum physics
• Condensed matter physics
• Statistical mechanics

Background:

• Anderson localization halts quantum transport via destructive interference.
• Fermi acceleration, driven by time-dependent random forces, enhances transport and is linked to cosmic rays.
• The interplay between these phenomena is complex, with limited experimental data.

Purpose of the Study:

• To experimentally investigate the dynamics of an ultracold Fermi gas in time-dependent disorder.
• To explore the competition between Anderson localization and Fermi acceleration.
• To observe distinct transport regimes (sub- to superdiffusion) in this driven quantum system.

Main Methods:

• Expansion of an ultracold Fermi gas.
• Introduction of time-dependent disorder.
• Observation of transport regimes using experimental measurements.

Main Results:

• Observed distinct sub- to superdiffusion regimes.
• Found that quantum interference unexpectedly counteracts Fermi acceleration in strong disorder.
• Identified a transition to a diffusive state in the driven system.

Conclusions:

• The study reveals complex dynamics arising from the competition between quantum interference and Fermi acceleration.
• The experimental system provides a platform for investigating Fermi acceleration within the quantum transport regime.
• Findings challenge simple models by showing interference effects on driven transport.