Abstract
The (im)possibility of local distinguishability of orthogonal multipartite quantum states still remains an intriguing question. Beyond , the problem remains unsolved even for maximally entangled states (MESs). So far, the only known condition for the local distinguishability of states is the well-known orthogonality preservation (OP). Using an upper bound on the locally accessible information for bipartite states, we derive a very simple necessary condition for any set of pairwise orthogonal MESs in to be perfectly locally distinguishable. It is seen that particularly when the number of pairwise orthogonal MES states in is equal to , then this necessary condition, along with the OP condition, imposes more constraints (for said states to be perfectly locally distinguishable) than the OP condition does. When testing this condition for the local distinguishability of all sets of four generalized Bell states in , we find that it is not only necessary but also sufficient to determine their local distinguishability. This demonstrates that the aforementioned upper bound may play a significant role in the general scenario of local distinguishability of bipartite states.
- Received 9 April 2017
- Revised 30 August 2017
DOI:https://doi.org/10.1103/PhysRevA.96.042314
©2017 American Physical Society