Spontaneous Parametric Down-Conversion and Quantum Walks in Arrays of Quadratic Nonlinear Waveguides

TL;DR

This paper explores how spontaneous parametric down-conversion in quadratic nonlinear waveguide arrays can generate and control quantum states with tunable spatial correlations, including switching between photon bunching and antibunching.

Contribution

It introduces a platform that combines photon pair generation with quantum walks, enabling classical control over quantum correlations in the output states.

Findings

Photon correlations can be switched from bunching to antibunching.

The control is achieved by varying temperature or pump beam profile.

The platform enables flexible quantum state engineering.

Abstract

We analyze the process of simultaneous photon pair generation and quantum walks realized by spontaneous parametric down conversion of a pump beam in a quadratic nonlinear waveguide array. We demonstrate that this flexible platform allows for creating quantum states with different spatial correlations. In particular, we predict that the output photon correlations can be switched from photon bunching to antibunching controlled entirely classically by varying the temperature of the array or the spatial profile of the pump beam.