Two-photon quantum walk in a multimode fiber

TL;DR

This paper demonstrates a quantum walk of indistinguishable photon pairs in a 380-mode multimode fiber, enabling complex quantum simulations and programmable high-dimensional optical circuits for advanced quantum technologies.

Contribution

It introduces a method to control two-photon states in a highly multimode fiber using wavefront shaping, advancing scalable quantum photonic networks.

Findings

Successful implementation of two-photon quantum walk in a 380-mode fiber

Controlled excitation of arbitrary output modes via classical and quantum interference

Establishment of a platform for high-dimensional multi-photon interference experiments

Abstract

Multi-photon propagation in connected structures - a quantum walk - offers the potential for simulating complex physical systems and provides a route to universal quantum computation. Increasing the complexity of quantum photonic networks where the walk occurs is essential for many applications. Here, we implement a quantum walk of indistinguishable photon pairs in a multimode fiber supporting 380 modes. Using wavefront shaping, we control the propagation of the two-photon state through the fiber in which all modes are coupled. Excitation of arbitrary output modes of the system is realized by controlling classical and quantum interferences. This experiment demonstrates a highly multimode platform for multi-photon interference experiments and provides a powerful method to program a general high-dimensional multiport optical circuit. This work paves the way for the next generation of photonic devices for quantum simulation, computing and communication.