Automated Discovery of Non-local Photonic Gates

TL;DR

This paper presents AI-discovered methods for implementing non-local photonic quantum gates using path indistinguishability, enabling distributed quantum processing without shared entanglement, and introduces new mechanisms akin to teleportation.

Contribution

The paper introduces AI-driven discovery of non-local photonic gates based on path indistinguishability, expanding quantum information processing techniques without relying on entanglement.

Findings

Discovered new non-local multiphoton gates using AI

Identified path indistinguishability as a practical resource

Uncovered a teleportation-like mechanism without entanglement

Abstract

Interactions between quantum systems enable quantum gates, the building blocks of quantum information processing. In photonics, direct photon-photon interactions are too weak to be practically useful, so effective interactions are engineered with linear optics and measurement. A central challenge is to realize such interactions non-locally, i.e., between photons that remain spatially separated. We present experimental proposals for several essential non-local multiphoton quantum gates that act on spatially separated photons, in both qubit and high-dimensional qudit systems. All solutions were discovered by the AI-driven discovery system called PyTheus. Rather than using pre-shared entanglement or Bell state measurements, our gates use as a resource quantum indistinguishability by path identity - a technique that exploits coherent superpositions of the photon pair origins. While analyzing these solutions, we uncovered a new mechanism that mimics much of the properties of quantum teleportation, without shared entanglement or Bell state measurements. Technically, our results establish path indistinguishability as a practical resource for distributed quantum information processing; conceptually, they demonstrate how automated discovery systems can contribute new ideas and techniques in physics.