Design and Analysis on a Cryogenic Current Amplifier with a Superconducting Microwave Resonator

TL;DR

This paper introduces a cryogenic current amplifier utilizing a superconducting microwave resonator with Josephson junctions, achieving significantly lower noise levels than traditional amplifiers, enabling advanced low-temperature device measurements.

Contribution

The paper presents a novel cryogenic current amplifier design based on superconducting resonators with Josephson junctions, offering lower noise and wider bandwidth capabilities.

Findings

Input-referred current noise is two orders of magnitude lower than conventional amplifiers.

Numerical analysis confirms the effectiveness of the superconducting resonator design.

Potential for improved measurements in low-temperature solid-state physics.

Abstract

We propose a new type of cryogenic current amplifiers, in which low-frequency power spectrum of current can be measured through a measurement of microwave response of a superconducting resonant circuit shunted by a series array of Josephson junctions. From numerical analysis on the equivalent circuit, the numerical value of the input-referred current noise of the proposed amplifier is found to be two orders of magnitude lower than the noise floor measured with the conventional cryogenic current amplifiers based on high-electron-mobility transistors or superconducting quantum interference devices. Our proposal can open new avenues for investigating low-temperature solid-state devices that require lower noise and wider bandwidth power spectrum measurements of current.