Theory of Fano effect in cavity quantum electrodynamics

TL;DR

This paper introduces a quantum master equation framework to describe the Fano effect in cavity QED systems, revealing the robustness of quantum interference against pure dephasing across different coupling regimes.

Contribution

It generalizes the Fano formula within a quantum master equation approach, enabling analysis of the effect under various conditions including pure dephasing and different coupling strengths.

Findings

Fano interference remains robust despite pure dephasing.

The framework applies to both weak and strong coupling regimes.

Provides a consistent formulation of emission spectra in cavity QED.

Abstract

We propose a Markovian quantum master equation that can describe the Fano effect directly, by assuming a standard cavity quantum electrodynamics system. The framework allows us to generalize the Fano formula, applicable over the weak and strong coupling regimes with pure dephasing. A formulation of its emission spectrum is also given in a consistent manner. We then find that the interference responsible for the Fano effect is robust against pure dephasing. This is counterintuitive because the impact of interference is, in general, severely reduced by decoherence processes. Our approach thus provides a basis for theoretical treatments of the Fano effect and new insights into the quantum interference in open quantum systems.