Measures of Decoherence

TL;DR

This paper investigates methods to quantify decoherence in quantum systems, proposing criteria and an operator norm approach to measure environmental effects on quantum coherence.

Contribution

It introduces a new operator norm-based method for quantifying decoherence and applies it to systems like spins interacting with bosonic baths.

Findings

Operator norm effectively measures decoherence levels.

Application to spin-boson systems demonstrates method's utility.

Provides criteria for assessing environmental decoherence.

Abstract

Methods for quantifying environmentally induced decoherence in quantum systems are investigated. We formulate criteria for measuring the degree of decoherence and consider several representative examples, including a spin interacting with the modes of a bosonic, e.g., phonon, bath. We formulate an approach based on the operator norm measuring the deviation of the actual density matrix from the ideal one which would describe the system without environmental interactions.