Coherent Destruction of Tunneling and Dark Floquet State

TL;DR

This paper introduces a dark Floquet state in a three-state system that suppresses tunneling, called dark coherent destruction of tunneling (DCDT), which generalizes known dark states and can be experimentally tested.

Contribution

It identifies a new dark Floquet state causing tunneling suppression and extends the concept of dark states to periodically driven systems.

Findings

Discovery of a dark Floquet state at zero quasienergy.

Demonstration of tunneling suppression via DCDT.

Potential for experimental verification with current technology.

Abstract

We study a system of three coherently coupled states, where one state is shifted periodically against the other two. We discover such a system possesses a dark Floquet state at zero quasienergy and always with negligible population at the intermediate state. This dark Floquet state manifests itself dynamically in terms of the suppression of inter-state tunneling, a phenomenon known as coherent destruction of tunneling. We suggest to call it dark coherent destruction of tunneling (DCDT). At high frequency limit for the periodic driving, this Floquet state reduces to the well-known dark state widely used for STIRAP. Our results can be generalized to systems with more states and can be verified with easily implemented experiments within current technologies.