Dispersive detection of single microwave photons with quantum dots

TL;DR

This paper proposes a theoretical method for detecting single microwave photons using quantum dots in a circuit QED setup, analyzing the detection efficiency and backaction effects.

Contribution

It introduces a quantum cascade approach for time-resolved detection of microwave photons via quantum dots, including a model for assessing detection efficiency and backaction.

Findings

Detection efficiency depends on coupling strength and tunneling rate.

Backaction influences the cavity mode during detection.

The method enables non-absorptive, dispersive photon detection.

Abstract

Within a circuit quantum electrodynamics architecture, we theoretically investigate the detection of a single propagating microwave photon traveling through a resonant microwave cavity dispersively interacting with a double quantum dot tunnel-coupled to a lead. Under suitable conditions, a single photon in the cavity can induce a measurable change in the electronic occupation of the charge states. We develop a quantum cascade approach that enables a time-resolved description of a single-photon wave packet impinging on the cavity. We make use of a simple model of charge detector to assess the efficiency of our photo-detection configuration as functions of key parameters such as coupling strength, tunneling rate, temperature, and photon resonance linewidth. We finally highlight a measurement-induced backaction effect on the cavity mode associated with the dispersive, non-absorptive detection process.