# A new coherence measure based on fidelity

## TL;DR

This paper introduces a new coherence measure for quantum states based on fidelity, which is analytically computable for qubits and useful for analyzing state transformations under incoherent operations.

## Contribution

A novel fidelity-based coherence measure for quantum states, with analytical computability for qubits and applications in state transformation analysis.

## Key findings

- Measure is analytically computable for arbitrary qubit states
- Can determine if one pure qubit state transforms into another via incoherent operations
- Provides a new tool for quantum coherence quantification

## Abstract

Quantifying coherence is an essential endeavor for both quantum foundations and quantum technologies. In this paper, we put forward a quantitative measure of coherence by following the axiomatic definition of coherence measures introduced in [T. Baumgratz, M. Cramer, and M. B. Plenio, Phys. Rev. Lett. 113, 140401 (2014)]. Our measure is based on fidelity and analytically computable for arbitrary states of a qubit. As one of its applications, we show that our measure can be used to examine whether a pure qubit state can be transformed into another pure or mixed qubit state only by incoherent operations.