Unifying different notions of quantum incompatibility into a strict hierarchy of resource theories of communication
Francesco Buscemi, Kodai Kobayashi, Shintaro Minagawa +2 more
While there is general consensus on the definition of incompatible POVMs, moving up to the level of instruments one finds a much less clear situation, with mathematically different and logically independent definitions of incompatibility. Here we close this gap by introducing the notion of q − c o m p a t i b i l i t y , which unifies different notions of POVMs, channels, and instruments incompatibility into one hierarchy of resource theories of communication between separated parties. The resource theories that we obtain are c o m p l e t e , in the sense that they contain complete families of free operations and monotones providing necessary and sufficient conditions for the existence of a transformation. Furthermore, our framework is fully o p e r a t i o n a l , in the sense that free transformations are characterized explicitly, in terms of local operations aided by causally-constrained directed classical communication, and all monotones possess a game-theoretic interpretation making them experimentally measurable in principle. We are thus able to pinpoint exactly what each notion of incompatibility consists of, in terms of information-theoretic resources.
arXiv:2211.09226•Quantum•Jun 7, 2023•25 citations