Quantitative Treatment of Decoherence

TL;DR

This paper discusses methods to define and quantify decoherence in quantum systems, proposing a norm-based measure that scales linearly with qubit number, and reviews its application to semiconductor quantum dot qubits.

Contribution

It introduces a norm-based measure for decoherence that is suitable for quantum registers and demonstrates its additivity across multiple qubits.

Findings

The proposed measure effectively quantifies decoherence in quantum systems.

The measure is additive and scales linearly with the number of qubits.

Application to semiconductor double quantum dot qubits illustrates its practical use.

Abstract

We outline different approaches to define and quantify decoherence. We argue that a measure based on a properly defined norm of deviation of the density matrix is appropriate for quantifying decoherence in quantum registers. For a semiconductor double quantum dot qubit, evaluation of this measure is reviewed. For a general class of decoherence processes, including those occurring in semiconductor qubits, we argue that this measure is additive: It scales linearly with the number of qubits.