Controlled decoherence in a quantum L\'evy kicked rotator

TL;DR

This paper develops a theory for quantum kicked rotators under combined amplitude and timing noise, revealing nonexponential coherence loss, subdiffusive momentum dynamics, and novel decay regimes, with analytical and numerical validation.

Contribution

It introduces a comprehensive model for quantum rotators with Le9vy noise, uncovering new nonexponential decoherence and subdiffusive behavior not previously characterized.

Findings

Nonexponential phase coherence loss observed.

Subdiffusive momentum dynamics demonstrated.

Distinct power-law decay regimes identified.

Abstract

We develop a theory describing the dynamics of quantum kicked rotators (modelling cold atoms in a pulsed optical field) which are subjected to combined amplitude and timing noise generated by a renewal process (acting as an engineered reservoir). For waiting-time distributions of variable exponent (L\'evy noise), we demonstrate the existence of a regime of nonexponential loss of phase coherence. In this regime, the momentum dynamics is subdiffusive, which also manifests itself in a non-Gaussian limiting distribution and a fractional power-law decay of the inverse participation ratio. The purity initially decays with a stretched exponential which is followed by two regimes of power-law decay with different exponents. The averaged logarithm of the fidelity probes the sprinkling distribution of the renewal process. These analytical results are confirmed by numerical computations on quantum kicked rotators subjected to noise events generated by a Yule-Simon distribution.