Generation of photonic tensor network states with Circuit QED

TL;DR

This paper proposes a circuit QED-based method to generate complex photonic tensor network states deterministically, leveraging cavity-qubit systems to produce highly entangled microwave photons with potential applications in quantum information processing.

Contribution

It introduces a novel circuit QED platform for deterministic generation of microwave photonic tensor network states, including 2D entangled states like projected entangled pair states.

Findings

High entanglement and bond dimension achievable with cavity ancilla

Generation of 2D entangled photonic states with complex structures

Platform capable of producing a broad class of tensor network states

Abstract

We propose a circuit QED platform and protocol to generate microwave photonic tensor network states deterministically. We first show that using a microwave cavity as ancilla and a transmon qubit as emitter is a good platform to produce photonic matrix product states. The ancilla cavity combines a large controllable Hilbert space with a long coherence time, which we predict translates into a high number of entangled photons and states with a high bond dimension. Going beyond this paradigm, we then consider a natural generalization of this platform, in which several cavity-qubit pairs are coupled to form a chain. The photonic states thus produced feature a two-dimensional entanglement structure and can be interpreted as $\textit{radial plaquette}$ projected entangled pair states [Wei, Malz, and Cirac, Phys. Rev. Lett. 128, 010607 (2022)], which include many paradigmatic states, such as the broad class of isometric tensor network states, graph states, and string-net states.