Quantum control gates with weak cross-Kerr nonlinearity

TL;DR

This paper proposes scalable quantum control gates using weak cross-Kerr nonlinearity, simplifying implementation and increasing success probabilities for optical quantum computing.

Contribution

Introduction of a novel C-path gate scheme enabling nearly deterministic bipartite POVMs and scalable quantum control gates with fewer resources.

Findings

Gates have higher success probabilities than linear optics counterparts.

Schemes are simpler and require fewer resources.

Potential for feasible implementation with current technology.

Abstract

In this paper, with the weak cross-Kerr nonlinearity, we first present a special experimental scheme called C-path gate with which the realization of all possible bipartite POVMs of two-photon polarization states can be simpler and nearly deterministic. Following the same technique, the schemes of the realization of quantum control gates have been proposed, including the CNOT gate (1/2), Fredkin gate (1/8), Toffoli gate (2/23), CU gate and even MCU gate. All these gates are scalable with the certain probabilities which are larger than those gates in linear optics. Less resource are required and the structures of these gates are so simple that we think they are feasible with current technology and may be useful for the realization of universal computation in optics.