Efficient quantum computing using coherent photon conversion

TL;DR

This paper introduces a deterministic photonic quantum processing scheme called coherent photon conversion, enabling scalable quantum computing with high-quality states, deterministic gates, and efficient detection, demonstrated experimentally with current technology.

Contribution

The paper presents a novel, versatile coherent photon conversion process that achieves deterministic quantum photonic operations, surpassing probabilistic methods and enabling scalable quantum computing architectures.

Findings

Experimental demonstration of a four-color nonlinear process for coherent photon conversion

Feasibility of implementing the scheme with current photonic crystal fibre technology

Potential applicability in various quantum systems beyond optics

Abstract

Single photons provide excellent quantum information carriers, but current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed single photons, while linear-optics gates are inherently probabilistic. Here, we introduce a deterministic scheme for photonic quantum information. Our single, versatile process---coherent photon conversion---provides a full suite of photonic quantum processing tools, from creating high-quality heralded single- and multiphoton states free of higher-order imperfections to implementing deterministic multiqubit entanglement gates and high-efficiency detection. It fulfils all requirements for a scalable photonic quantum computing architecture. Using photonic crystal fibres, we experimentally demonstrate a four-colour nonlinear process usable for coherent photon conversion and show that current technology provides a feasible path towards deterministic operation. Our scheme, based on interacting bosonic fields, is not restricted to optical systems, but could also be implemented in optomechanical, electromechanical and superconducting systems which exhibit extremely strong intrinsic nonlinearities.