Abstract
We explicitly exhibit a set of four ququad-ququad orthogonal maximally entangled states that cannot be perfectly distinguished by means of local operations and classical communication. Before our work, it was unknown whether there is a set of locally indistinguishable orthogonal maximally entangled states for some positive integer . We further show that a maximally entangled state can be used to locally distinguish this set of states without being consumed, thus demonstrate a novel phenomenon of entanglement discrimination catalysis. Based on this set of states, we construct a new set consisting of four locally indistinguishable states such that (with members) is locally distinguishable for some greater than one. As an immediate application, we construct a noisy quantum channel with one sender and two receivers whose local zero-error classical capacity can achieve the full dimension of the input space but only with a multi-shot protocol.
- Received 21 February 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.020506
© 2012 American Physical Society