Programmable Multimode Quantum Networks

TL;DR

This paper introduces a versatile method for generating and switching between various multimode entangled states in quantum optics using a single beam and multi-pixel detectors, enhancing scalability and flexibility.

Contribution

The authors develop a programmable approach to create and emulate multiple linear optics networks for multimode entanglement, reducing complexity and enabling real-time switching.

Findings

Successfully generated entangled states from N=2 to N=8 modes.

Demonstrated real-time switching between different entangled states.

Achieved generation of cluster states for N=2,3,4 modes.

Abstract

Entanglement between large numbers of quantum modes is the quintessential resource for future technologies such as the quantum internet. Conventionally the generation of multimode entanglement in optics requires complex layouts of beam-splitters and phase shifters in order to transform the input modes in to entangled modes. These networks need substantial modification for every new set of entangled modes to be generated. Here we report on the highly versatile and efficient generation of various multimode entangled states with the ability to switch between different linear optics networks in real time. By defining our modes to be combinations of different spatial regions of one beam, we may use just one pair of multi-pixel detectors each with M photodiodes in order to measure N entangled modes, with a maximum number of N=M modes. We program virtual networks that are fully equivalent to the physical linear optics networks they are emulating. We present results for N=2 up to N=8 entangled modes here, including N=2,3,4 cluster states. Our approach introduces flexibility and scalability to multimode entanglement, two important attributes that are highly sought after in state of the art devices.