Monitoring Decoherence via Measurement of Quantum Coherence

TL;DR

This paper presents a theoretical analysis of how environment-induced decoherence affects quantum coherence in a multi-slit interference experiment, proposing a method to quantify decoherence through direct measurement of quantum coherence.

Contribution

It introduces an exact expression for quantum coherence in the presence of decoherence and demonstrates how to determine decoherence time from coherence measurements in a two-slit setup.

Findings

Derived an exact formula for coherence as a function of environmental parameters.

Showed that decoherence time can be obtained from measured coherence values.

Highlighted the relevance for quantum information and quantum computing applications.

Abstract

A multi-slit interference experiment, with which-way detectors, in the presence of environment induced decoherence, is theoretically analyzed. The effect of environment is modeled via a coupling to a bath of harmonic oscillators. Through an exact analysis, an expression for $\mathcal{C}$, a recently introduced measure of coherence, of the particle at the detecting screen is obtained as a function of the parameters of the environment. It is argued that the effect of decoherence can be quantified using the measured coherence value which lies between zero and one. For the specific case of two slits, it is shown that the decoherence time can be obtained from the measured value of the coherence, $\mathcal{C}$, thus providing a novel way to quantify the effect of decoherence via direct measurement of quantum coherence. This would be of significant value in many current studies that seek to exploit quantum superpositions for quantum information applications and scalable quantum computation.