A universal two-bit gate for quantum computation
Adriano Barenco · Proceedings of the Royal Society of London Series A Mathematical and Physical Sciences · 1995
Abstract We prove the existence of a class of two-input, two-output gates any one of which is universal for quantum computation. This is done by explicitly constructing the three-bit gate introduced by Deutsch ( Proc. R. Soc. Lond. A 425, 73 (1989)) as a network consisting of replicas of a single two-bit gate.