Exchange Symmetry in Multiphoton Quantum Interference

TL;DR

This paper explores the complex exchange symmetries of multi-photon states, revealing new interference phenomena and the ability to tune quantum statistics, which advances understanding and control in quantum photonics.

Contribution

It uncovers the rich landscape of exchange symmetries in multi-photon states and demonstrates experimental control over these symmetries in three-photon interference.

Findings

Multi-photon states exhibit diverse exchange symmetries including bosonic, fermionic, and anyonic.

Interference effects can be controlled by tuning pairwise symmetries.

New quantum statistics can be accessed and manipulated in scalable photonic systems.

Abstract

Photons are bosons, and yet, when prepared in specific entangled states, they can exhibit non-bosonic behaviour. While this phenomenon has so far been studied in two-photon systems, exchange symmetries and interference effects in multi-photon scenarios remain largely unexplored. In this work, we show that multi-photon states uncover a rich landscape of exchange symmetries. With three photons already, multiple pairwise combinations are possible, where each pair of photons can exhibit either bosonic, fermionic, or anyonic exchange symmetry. This gives rise to mixed symmetry systems that are not possible to achieve with two photon alone. We experimentally investigate how these symmetry configurations manifest themselves in the observed interference of three photons. We show that multi-photon interference can be effectively turned on and off by tuning the symmetry of the constituent pairs. The possibility of accessing and tuning new quantum statistics in a scalable photonic platform not only deepens our understanding of quantum systems, but is also highly relevant for quantum technologies that rely on quantum interference.