Strong Anderson localization in cold atom quantum quenches.

Area of Science:

• Quantum physics
• Condensed matter physics
• Atomic physics

Background:

• Anderson localization describes the suppression of wave function propagation in disordered systems.
• Cold atom clouds in speckle potentials provide a controllable platform for studying quantum phenomena.
• Quantum quenches induce non-equilibrium dynamics, leading to novel states of matter.

Purpose of the Study:

• To investigate signatures of Anderson localization in the momentum distribution of cold atoms after a quantum quench.
• To identify unique indicators of strong Anderson localization beyond traditional weak localization phenomena.
• To provide a comprehensive theoretical description of the diffusion-to-localization crossover.

Main Methods:

• Simulation of a quasi-one-dimensional cold atom cloud.
• Preparation in a well-defined initial momentum state.
• Expansion in a disorder speckle potential.
• Nonperturbative and time-resolved theoretical analysis.

Main Results:

• Observation of a distinct peak in the forward scattering amplitude of the momentum distribution.
• This forward peak serves as a signature of strong Anderson localization, differing from weak localization backscattering.
• The study covers the full crossover from diffusive to localized behavior.

Conclusions:

• The identified forward scattering peak is a robust signature of strong Anderson localization in cold atom systems.
• The theoretical framework captures the dynamics across the diffusion-localization transition.
• Experimental verification of these findings is feasible with current technology.