Protected quantum coherence by gain and loss in a noisy quantum kicked rotor

We study the effects of non-Hermiticity on quantum coherence via a noisy quantum kicked rotor (NQKR). The random noise comes from the fluctuations in kick amplitude at each time. The non-Hermitian driving indicates the imaginary kicking potential, representing the environment-induced atom gain and loss. In the absence of gain and loss, the random noise destroys quantum coherence manifesting dynamical localization, which leads to classical diffusion. Interestingly, in the presence of non-Hermitian kicking potential, the occurrence of dynamical localization is highly sensitive to the gain and loss, manifesting the restoration of quantum coherence. Using the inverse participation ratio arguments, we numerically obtain a phase diagram of the classical diffusion and dynamical localization on the parameter plane of noise amplitude and non-Hermitian driving strength. With the help of analysis on the corresponding quasieigenstates, we achieve insight into dynamical localization, and uncover that the origin of the localization is interference between multiple quasi-eigenstates of the quantum kicked rotor. We further propose an experimental scheme to realize the NQKR in a dissipative cold atomic gas, which paves the way for future experimental investigation of an NQKR and its anomalous non-Hermitian properties.

Automated summary

We investigate the impact of non-Hermiticity on quantum coherence using a noisy quantum kicked rotor (NQKR). Random noise from kick amplitude fluctuations destroys quantum coherence, but the presence of non-Hermitian kicking potential can restore it by interacting with gain and loss. By studying the phase diagram of classical diffusion and dynamical localization, we find that the localization arises from interference between multiple quasi-eigenstates of the quantum kicked rotor. This research provides insight into the restoration of quantum coherence and suggests an experimental scheme to study NQKR in a dissipative cold atomic gas.