Quantum walks of two correlated photons in a 2D synthetic lattice

TL;DR

This paper demonstrates a scalable, discrete-time quantum walk of two correlated photons in a 2D synthetic lattice, advancing quantum simulation capabilities in photonic systems.

Contribution

It introduces a novel platform for two-particle quantum walks in 2D lattices using optical modes and polarization control, enabling complex quantum simulations.

Findings

Successful implementation of two-photon quantum walks in 2D

Platform is compact, efficient, and scalable

Potential applications in quantum simulation and topological photonics

Abstract

Quantum walks represent paradigmatic quantum evolutions, enabling powerful applications in the context of topological physics and quantum computation. They have been implemented in diverse photonic architectures, but the realization of a two-particle dynamics on a multi-dimensional lattice has hitherto been limited to continuous-time evolutions. To fully exploit the computational capabilities of quantum interference it is crucial to develop platforms handling multiple photons that propagate across multi-dimensional lattices. Here, we report a discrete-time quantum walk of two correlated photons in a two-dimensional lattice, synthetically engineered by manipulating a set of optical modes carrying quantized amounts of transverse momentum. Mode-couplings are introduced via the polarization-controlled diffractive action of thin geometric-phase optical elements. The entire platform is compact, efficient, scalable, and represents a versatile tool to simulate quantum evolutions on complex lattices. We expect that it will have a strong impact on diverse fields such as quantum state engineering, topological quantum photonics, and Boson Sampling.