A universal two-bit gate for quantum computation

TLDR

The authors aim to prove the existence of a class of two‑input, two‑output gates that are universal for quantum computation. They explicitly construct Deutsch’s three‑bit gate as a network of replicas of a single two‑bit gate. They succeed in proving that such gates exist and are universal for quantum computation. Published in the Proceedings of the Royal Society of London.

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.