Global Coherence in Quantum Discord as a Resource
Abstract
This work addresses which aspect of bipartite coherence in quantum discord is essential for genuinely quantum correlation. To this end, global coherence of bipartite states is defined as a form of bipartite coherence that is not local coherence in either of the subsystems or in both subsystems alone, and we identify it as being indicated by a witness of discord. With global coherence as a resource, any local operations of the form A B, which may create coherence locally, are free operations. This implies that with global coherence as a resource for operational tasks, any local operations can be freely used, but require classical randomness not to be freely available. Using this identification, we demonstrate that global coherence is a necessary resource for the task of semi-device-independent steerability of quantum discord. On the other hand, for the task of remote state preparation using quantum discord in two-qubit states, a necessary and sufficient quantum resource is identified by invoking a witness of global coherence.
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.