Decay of fidelity in terms of correlation functions

TL;DR

This paper investigates how the fidelity of qubits in open systems decays over time by linking it to correlation functions and spectral properties, providing insights relevant for quantum memory models.

Contribution

It introduces a formalism connecting fidelity decay to correlation functions and spectral gaps, enhancing understanding of quantum memory stability.

Findings

Fidelity decay is related to correlation function evolution.

In Markovian dynamics, decay links to spectral gap of the generator.

Results aid in analyzing quantum memory models.

Abstract

We consider, within the algebraic formalism, the time dependence of fidelity for qubits encoded into an open physical system. We relate the decay of fidelity to the evolution of correlation functions and, in the particular case of a Markovian dynamics, to the spectral gap of the generator of the semigroup. The results are applicable to the analysis of models of quantum memories.