Approaching energy quantum limit detection of microwave photons with Josephson Junctions

TL;DR

This paper explores the potential of using current-biased Josephson Junctions to detect microwave photons at the energy quantum limit, aiming to improve sensitivity beyond conventional room-temperature methods.

Contribution

It introduces a numerical simulation approach to evaluate the discriminability of microwave signals using CBJJ detectors, predicting their ability to resolve about a dozen photons.

Findings

CBJJ detectors can potentially approach the energy quantum limit for microwave photon detection.

Numerical simulations show the discriminability between events with and without microwave driving.

Feasibility of achieving EQLD with CBJJ detectors is discussed.

Abstract

Single-photon detection is an energy quantum limit detection (EQLD) of a significantly weak electromagnetic wave. Given the sensitivity of the conventional electromagnetic induction microwave receiver working at room-temperature is very limited, due to the significantly strong thermal noise, here we analyze the possibility of approaching the EQLD of the weak microwave signal by using a current-biased Josephson Junction (CBJJ) detector. By numerically simulating the dynamics for the phase particle of the CBJJ, we propose an approach to describe the discriminability between the probabilistically escaped events of the phase particle with and without the microwave current driving, by measuring the minimum $d_{\rm KC}$-index. We predicate that, the experimentally demonstrated CBJJ detectors possess the ability to resolve about a dozen photons. The feasibility of the desired EQLD of microwave signal by using the CBJJ detector is also discussed.