A coherence measure based on the angle between quantum states

Quantum coherence is regarded as a fundamental ingredient in quantum information processing tasks. Quantifying coherence of states is a crucial problem, which has attracted a growing interest for scientists. In this paper, we put forward a quantitative measure of coherence based on the angle between quantum states. Rigorous proof shows that the proposed coherence measure fulfills all the axioms dictated by the resource theory of quantum coherence measure. Furthermore, a strong relation between coherence measure based on the angle and entanglement measure based on fidelity is derived.