Large-scale cluster quantum microcombs

TL;DR

This paper demonstrates the generation of large-scale, programmable quantum cluster states using integrated microresonators, advancing scalable quantum computing and communication technologies with on-chip photonics.

Contribution

It introduces a method to generate and program large-scale quantum cluster states on a chip using microresonators and multi-frequency lasers, achieving unprecedented scale and squeezing levels.

Findings

Deterministic creation of 60-qumode continuous-variable cluster states.

Programmable graph structures in one- and two-dimensional lattices.

Largest-scale cluster states with high raw squeezing levels from a photonic chip.

Abstract

An optical frequency comb comprises a cluster of equally spaced, phase-locked spectral lines. Replacing these classical components with correlated quantum light gives rise to cluster quantum frequency combs, providing abundant quantum resources for measurement-based quantum computation and multi-user quantum networks. We propose and generate cluster quantum microcombs within an on-chip optical microresonator driven by multi-frequency lasers. Through resonantly enhanced four-wave mixing processes, continuous-variable cluster states with 60 qumodes are deterministically created. The graph structures can be programmed into one- and two-dimensional lattices by adjusting the configurations of the pump lines, which are confirmed inseparable based on the measured covariance matrices. Our work demonstrates the largest-scale cluster states with unprecedented raw squeezing levels from a photonic chip, offering a compact and scalable platform for computational and communicational tasks with quantum advantages.