Coherent back and forward scattering peaks in the quantum kicked rotor

TL;DR

This paper proposes an experimental scheme using the quantum kicked rotor to observe the coherent forward scattering peak, a phenomenon linked to strong localization, complementing the well-known backscattering peak.

Contribution

It introduces a method to observe the elusive coherent forward scattering in conservative disordered systems using the quantum kicked rotor platform.

Findings

Numerical simulations confirm the presence of coherent forward scattering in the quantum kicked rotor.

The proposed scheme is feasible with current cold-atom experimental techniques.

The study compares orthogonal and unitary classes of disordered quantum systems.

Abstract

We propose and analyze an experimental scheme using the quantum kicked rotor to observe the newly-predicted coherent forward scattering peak together with its long-known twin brother, the coherent backscattering peak. Contrary to coherent backscattering, which arises already under weak-localization conditions, coherent forward scattering is only triggered by Anderson or strong localization. So far, coherent forward scattering has not been observed in conservative systems with elastic scattering by spatial disorder. We propose to turn to the quantum kicked rotor, which has a long and succesful history as an accurate experimental platform to observe dynamical localization, i.e., Anderson localization in momentum space. We analyze the coherent forward scattering effect for the quantum kicked rotor by extensive numerical simulations, both in the orthogonal and unitary class of disordered quantum systems, and show that an experimental realization involving phase-space rotation techniques is within reach of state-of-the-art cold-atom experiments.