# Interferometric visibility and coherence

## TL;DR

This paper links quantum coherence to interference visibility in multi-path interferometers, providing a framework to derive coherence measures from observable interference patterns, including known and new measures.

## Contribution

It introduces a general method to derive quantum coherence measures from interference visibility, connecting theoretical coherence quantification with experimental observables.

## Key findings

- Recovered known coherence measures from visibility parameters
- Derived new coherence measures based on interference visibility
- Established a framework connecting interference patterns to quantum coherence

## Abstract

Recently, the basic concept of quantum coherence (or superposition) has gained a lot of renewed attention, after Baumgratz et al. [PRL 113:140401 (2014)], following \AA{}berg [arXiv:quant-ph/0612146], have proposed a resource theoretic approach to quantify it. This has resulted in a large number of papers and preprints exploring various coherence monotones, and debating possible forms for the resource theory. Here we take the view that the operational foundation of coherence in a state, be it quantum or otherwise wave mechanical, lies in the observation of interference effects. Our approach here is to consider an idealised multi-path interferometer, with a suitable detector, in such a way that the visibility of the interference pattern provides a quantitative expression of the amount of coherence in a given probe state. We present a general framework of deriving coherence measures from visibility, and demonstrate it by analysing several concrete visibility parameters, recovering some known coherence measures and obtaining some new ones.