Resonant Perturbation Theory of Decoherence and Relaxation of Quantum Bits

TL;DR

This paper introduces a rigorous resonant perturbation theory to analyze decoherence and relaxation in multi-qubit quantum systems coupled to bosonic reservoirs, avoiding master equation approximations.

Contribution

It provides a general, exact framework for understanding decoherence in complex quantum systems without relying on traditional approximations.

Findings

Derives a representation of reduced dynamics valid for all times

Applicable to a wide range of systems beyond solvable models

Does not depend on master equation approximations

Abstract

We describe our recent results on the resonant perturbation theory of decoherence and relaxation for quantum system with many qubits. The approach represents a rigorous analysis of the phenomenon of decoherence and relaxation for general $N$-level systems coupled to reservoirs of the bosonic fields. We derive a representation of the reduced dynamics valid for all times $t\geq 0$ and for small but fixed interaction strength. Our approach does not involve master equation approximations and applies to a wide variety of systems which are not explicitly solvable.