Decoherence in a superconducting quantum bit circuit

TL;DR

This paper investigates decoherence in superconducting qubits, specifically the quantronium, using NMR-inspired experiments and a spectral density framework to analyze noise sources and explore mitigation strategies.

Contribution

It introduces a general spectral density framework for analyzing decoherence in superconducting qubits and applies it to the quantronium, providing insights into noise sources and potential mitigation methods.

Findings

Identified dominant noise sources affecting the qubit

Developed a spectral density analysis framework

Suggested methods to reduce decoherence

Abstract

Decoherence in quantum bit circuits is presently a major limitation to their use for quantum computing purposes. We present experiments, inspired from NMR, that characterise decoherence in a particular superconducting quantum bit circuit, the quantronium. We introduce a general framework for the analysis of decoherence, based on the spectral densities of the noise sources coupled to the qubit. Analysis of our measurements within this framework indicates a simple model for the noise sources acting on the qubit. We discuss various methods to fight decoherence.