Local Distinguishability of Multipartite Unitary Operations
Runyao Duan, Yuan Feng, Mingsheng Ying · Physical Review Letters · 2008
We show that any two different unitary operations acting on an arbitrary multipartite quantum system can be perfectly distinguished by local operations and classical communication when a finite number of runs is allowed. Intuitively, this result indicates that the lost identity of a nonlocal unitary operation can be recovered locally. No entanglement between distant parties is required.