Abstract:
The resource theory of coherence describes the extent to which quantum properties manifest in a given quantum system. Although coherence has been extensively studied for individual quantum states, coherence for ensembles of quantum states remains an area of active research. The entanglement-based approach to ensemble coherence relates it to the resource of entanglement and to measurement uncertainty. This work presents two methods for generating ensemble coherence from a given entanglement resource between two qubit systems. The first method involves applying a von Neumann measurement to one part of a non-maximally entangled bipartite state, which results in a pair of non-orthogonal states whose coherence may be equal to the original measure of entanglement. The second method involves applying a class of symmetric observables capable of generating ensembles used in quantum key distribution (QKD) protocols, such as B92, BB84, and three-state QKD. Thus, this work demonstrates how much coherence can be obtained from a given resource of coherence.
