Alternative framework for quantifying coherence

TL;DR

This paper introduces a new, flexible framework for quantifying quantum coherence based on additivity properties, applicable across different physical contexts and compatible with existing measures.

Contribution

It presents an operation-independent framework for coherence quantification, enhancing flexibility and resolving open questions in the field.

Findings

Framework is compatible with all known coherence measures

Allows for simpler and more versatile coherence quantification

Facilitates resolution of open questions in coherence research

Abstract

We propose an alternative framework for quantifying coherence. The framework is based on a natural property of coherence, the additivity of coherence for subspace-independent states, which is described by an operation-independent equality rather than operation-dependent inequalities and therefore applicable to various physical contexts. Our framework is compatible with all the known results on coherence measures but much more flexible and convenient for applications, and by using it many open questions can be resolved.