A comprehensive look at quantum coherence

A comprehensive look at quantum coherence

Quantum coherence is one of the unique features of quantum systems, and the existence of this feature is the reason for the theoretical superiority of classical algorithms over their classical counterparts. In simple terms, quantum coherence means that the quantum state of the system is placed in the superposition of its allowed levels. In this presentation, we will state the exact definition of quantum coherence and discuss the principles of its quantification methods, especially the resource theory of quantum coherence. In the following, we introduce hypercoherent states that are considered a quantum resource and discuss why these states are considered quantum resources. Finally, we talk about the fact that the concept of coherence is inevitably tied to the concept of quantum measurement, and on this basis we define and quantify quantum coherence based on available measurements.