A simple scheme for universal linear optics quantum computing with constant experimental complexity using fiber-loops

TL;DR

This paper proposes a fiber-loop architecture for universal linear optics quantum computing that maintains constant experimental complexity regardless of the computation size, simplifying implementation.

Contribution

It introduces a modified fiber-loop scheme enabling universal quantum computing with minimal and constant experimental complexity.

Findings

Constant experimental complexity independent of computation size

Single interference point simplifies alignment

Feasible with current fiber and detector technology

Abstract

Recently, Motes, Gilchrist, Dowling & Rohde [Phys. Rev. Lett. 113, 120501 (2014)] presented a scheme for photonic boson-sampling using a fiber-loop architecture. Here we show that the same architecture can be modified to implement full, universal linear optics quantum computing, in various incarnations. The scheme employs two embedded fiber-loops, a single push-button photon source, three dynamically controlled beamsplitters, and a single time-resolved photo-detector. The architecture has only a single point of interference, and thus may be significantly easier to align than other schemes. The experimental complexity of the scheme is constant, irrespective of the size of the computation, limited only by fiber lengths and their respective loss rates.