Microwave Photon Detector in Circuit QED

TL;DR

This paper proposes a high-efficiency microwave photon detector using a metamaterial of superconducting elements in circuit QED, enabling advanced quantum information processing with microwave photons.

Contribution

It introduces a novel design of a microwave photon detector based on superconducting circuits, addressing the lack of such detectors in circuit QED.

Findings

Design achieves high detection efficiency

Applicable to various physical systems

Can be generalized to a microwave photon counter

Abstract

Quantum optical photodetection has occupied a central role in understanding radiation-matter interactions. It has also contributed to the development of atomic physics and quantum optics, including applications to metrology, spectroscopy, and quantum information processing. The quantum microwave regime, originally explored using cavities and atoms, is seeing a novel boost with the generation of nonclassical propagating fields in circuit quantum electrodynamics (QED). This promising field, involving potential developments in quantum information with microwave photons, suffers from the absence of photodetectors. Here, we design a metamaterial composed of discrete superconducting elements that implements a high-efficiency microwave photon detector. Our design consists of a microwave guide coupled to an array of metastable quantum circuits, whose internal states are irreversibly changed due to the absorption of photons. This proposal can be widely applied to different physical systems and can be generalized to implement a microwave photon counter.