Nondestructive readout for a superconducting flux qubit

TL;DR

This paper introduces a nondestructive readout technique for superconducting flux qubits using Josephson inductance measurement, enabling fast, efficient, and minimally invasive quantum state detection suitable for quantum computing.

Contribution

The paper presents a novel readout method based on Josephson inductance measurement, improving speed and reducing back-action in flux qubit state detection.

Findings

Achieved flux detection efficiency suitable for quantum computing

Measured qubit relaxation times around 80 microseconds

Demonstrated spectroscopy of a flux qubit

Abstract

We present a new readout method for a superconducting flux qubit, based on the measurement of the Josephson inductance of a superconducting quantum interference device that is inductively coupled to the qubit. The intrinsic flux detection efficiency and back-action are suitable for a fast and nondestructive determination of the quantum state of the qubit, as needed for readout of multiple qubits in a quantum computer. We performed spectroscopy of a flux qubit and we measured relaxation times of the order of 80 $\mu s$.