A versatile quantum walk resonator with bright classical light

TL;DR

This paper introduces a scalable resonator setup that enables quantum walks using bright classical light, simplifying implementation and broadening practical applications without needing quantum states of light.

Contribution

A versatile resonator configuration for quantum walks with bright classical light, eliminating the need for quantum states and allowing arbitrary step numbers without complex optics.

Findings

Successfully implemented various quantum walks on a single platform

Demonstrated scalability with arbitrary number of steps

Showed that quantum walks do not require quantum light states

Abstract

In a Quantum Walk (QW) the "walker" follows all possible paths at once through the principle of quantum superposition, differentiating itself from classical random walks where one random path is taken at a time. This facilitates the searching of problem solution spaces faster than with classical random walks, and holds promise for advances in dynamical quantum simulation, biological process modelling and quantum computation. Current efforts to implement QWs have been hindered by the complexity of handling single photons and the inscalability of cascading approaches. Here we employ a versatile and scalable resonator configuration to realise quantum walks with bright classical light. We experimentally demonstrate the versatility of our approach by implementing a variety of QWs, all with the same experimental platform, while the use of a resonator allows for an arbitrary number of steps without scaling the number of optics. Our approach paves the way for practical QWs with bright classical light and explicitly makes clear that quantum walks with a single walker do not require quantum states of light.