title: Demonstration of nondeterministic quantum logic operations using linear optical elements.
abstract: Knill, Laflamme, and Milburn [Nature (London) 409, 46 (2001)] recently showed that nondeterministic quantum logic operations could be performed using linear optical elements, additional photons (ancilla), and postselection based on the output of single-photon detectors. Here we report the experimental demonstration of two logic devices of this kind, a destructive controlled-NOT (CNOT) gate and a quantum parity check. These two devices can be combined with a pair of entangled photons to implement a conventional (nondestructive) CNOT that succeeds with a probability of 1/4.
authors.affiliation: The Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland 20723, USA.
authors.forename: T B
authors.initials: TB
authors.lastname: Pittman
authors.forename: B C
authors.initials: BC
authors.lastname: Jacobs
authors.forename: J D
authors.initials: JD
authors.lastname: Franson