Itinerant microwave photon detector

TL;DR

This paper proposes a high-efficiency, quantum non-demolition microwave photon detector using dark states in circuit QED, capable of continuous photon detection with high fidelity.

Contribution

It introduces a novel scheme employing long-lived dark states in artificial atoms to enhance microwave photon detection efficiency.

Findings

High detection fidelities are achievable with realistic parameters.

The scheme allows continuous measurement of photon presence and arrival time.

Utilizes inhomogeneous artificial atoms to extend interaction time without back-action.

Abstract

The realization of a high-efficiency microwave single photon detector is a long-standing problem in the field of microwave quantum optics. Here we propose a quantum non-demolition, high-efficiency photon detector that can readily be implemented in present state-of-the-art circuit quantum electrodynamics. This scheme works in a continuous fashion, gaining information about the arrival time of the photon as well as about its presence. The key insight that allows to circumvent the usual limitations imposed by measurement back-action is the use of long-lived dark states in a small ensemble of inhomogeneous artificial atoms to increase the interaction time between the photon and the measurement device. Using realistic system parameters, we show that large detection fidelities are possible.