An RF-Driven Josephson Bifurcation Amplifier for Quantum Measurements

TL;DR

This paper introduces a novel RF-driven Josephson bifurcation amplifier designed for quantum bit readout, offering high speed, sensitivity, and minimal back-action without on-chip dissipation, validated by experimental measurements.

Contribution

The paper presents a new type of superconducting amplifier based on Josephson bifurcation, demonstrating theoretical predictions with experimental validation.

Findings

Achieves high sensitivity and low back-action in quantum measurements

Operates near a dynamical bifurcation point for optimal performance

Experimental results match theoretical predictions

Abstract

We have constructed a new type of amplifier whose primary purpose is the readout of superconducting quantum bits. It is based on the transition of an RF-driven Josephson junction between two distinct oscillation states near a dynamical bifurcation point. The main advantages of this new amplifier are speed, high-sensitivity, low back-action, and the absence of on-chip dissipation. Pulsed microwave reflection measurements on nanofabricated Al junctions show that actual devices attain the performance predicted by theory.