Regional vs global operations - Quantum battery and state discrimination tasks

We will consider energy extraction from quantum batteries and quantum state discrimination by using local quantum operations.

Considering a two-party quantum battery comes with the dichotomy between choosing global and local measurements, since the former provides more energy but the latter is cheaper. We introduce the concept of local passivity for shared quantum batteries with local Hamiltonians and characterise the set of all locally passive battery states. For generic battery states, whether noiseless or noisy, we find that the relationship between energy extractions by local and global operations is closely related to the entanglement content. The relation between incompatibility of measurements and quantum state discrimination tasks is well explored in the context of global operations. We examine the same by considering state discrimination using local operations and classical communication.