Photonic random walks with traps

TL;DR

This paper explores the contrasting behaviors of classical and quantum photonic random walks in one-dimensional lattices with traps, revealing that quantum walks can persist indefinitely despite traps, unlike classical walks.

Contribution

It demonstrates the persistent nature of quantum photonic walks in the presence of traps and introduces a controllable system to switch between quantum and classical behaviors.

Findings

Quantum walks can avoid destruction by traps, unlike classical walks.

Synthetic mesh lattices enable control over decoherence and walk behavior.

Quantum walks can continue indefinitely despite the presence of traps.

Abstract

Random walks behave very differently for classical and quantum particles. Here we unveil a ubiquitous distinctive behavior of random walks of a photon in a one-dimensional lattice in the presence of a finite number of traps, at which the photon can be destroyed and the walk terminates. While for a classical random walk the photon is unavoidably destroyed by the traps, for a quantum walk the photon can remain alive and the walk continues forever. Such an intriguing behavior is illustrated by considering photonic random walks in synthetic mesh lattices with controllable decoherence, which enables to switch from quantum to classical random walks.