Multi-level interference resonances in strongly-driven three-level systems

TL;DR

This paper investigates multi-photon resonances in a strongly-driven three-level quantum system, revealing interference effects and robustness to fluctuations, with implications for solid-state and atomic systems.

Contribution

It introduces a new understanding of interference phenomena in multi-level systems under strong driving, explaining experimental observations in quantum dots.

Findings

Distinct behavior for even and odd photon resonances

Interference effects are insensitive to energy fluctuations

Resonance phenomena persist under strong dephasing

Abstract

We study multi-photon resonances in a strongly-driven three-level quantum system, where one level is periodically swept through a pair of levels with constant energy separation $E$. Near the multi-photon resonance condition $n\hbar\omega = E$, where $n$ is an integer, we find qualitatively different behavior for $n$ even or odd. We explain this phenomenon in terms of families of interfering trajectories of the multi-level system. Remarkably, the behavior is insensitive to fluctuations of the energy of the driven level, and survives deep into the strong dephasing regime. The setup can be relevant for a variety of solid state and atomic or molecular systems. In particular, it provides a clear mechanism to explain recent puzzling experimental observations in strongly-driven double quantum dots.