Characterization of a flux-driven Josephson parametric amplifier with near quantum-limited added noise for axion search experiments

TL;DR

This paper demonstrates a flux-driven Josephson parametric amplifier operating near the quantum noise limit at 2.3 GHz, significantly improving the sensitivity of axion detection experiments by reducing added noise in the signal chain.

Contribution

It introduces a flux-driven JPA with near quantum-limited noise performance suitable for axion search experiments, enhancing detection sensitivity.

Findings

Achieved noise temperatures as low as 120 mK in the detection chain.

Operated the JPA at 19 dB gain at 2.3 GHz.

Demonstrated the amplifier's effectiveness in a realistic axion detection setup.

Abstract

The axion, a hypothetical elementary pseudoscalar, is expected to solve the strong CP problem of QCD and is also a promising candidate for dark matter. The most sensitive axion search experiments operate at millikelvin temperatures and hence rely on instrumentation that carries signals from a system at cryogenic temperatures to room temperature instrumentation. One of the biggest limiting factors affecting the parameter scanning speed of these detectors is the noise added by the components in the signal detection chain. Since the first amplifier in the chain limits the minimum noise, low-noise amplification is of paramount importance. This paper reports on the operation of a flux-driven Josephson parametric amplifier (JPA) operating at around 2.3 GHz with added noise approaching the quantum limit. The JPA was employed as a first stage amplifier in an experimental setting similar to the ones used in haloscope axion detectors. By operating the JPA at a gain of 19 dB and cascading it with two cryogenic amplifiers operating at 4 K, noise temperatures as low as 120 mK were achieved for the whole signal detection chain.