Scalable Optical Quantum State Synthesizer with Dual-Mode Resonator Memory

TL;DR

This paper presents a scalable optical quantum state synthesizer using a dual-mode resonator memory that enables efficient storage, retrieval, and entangling of non-Gaussian states, advancing optical quantum computing and related fields.

Contribution

It introduces a novel dual-mode resonator memory supporting continuous-time storage and entangling operations, demonstrated through scalable generation of non-Gaussian states like cat and GKP states.

Findings

Achieved up to 93% efficiency in storing squeezed single-photon states.

Demonstrated full writing, storage, and readout in an optical resonator memory.

Validated the memory's coherence with T1 = 2.3 μs and Tϕ = 0.96 μs.

Abstract

Optical quantum computing is a promising approach for achieving large-scale quantum computation. While Gaussian operations have been successfully scaled, the inherently weak nonlinearity in optics makes generating highly non-Gaussian states a critical challenge for universality and fault tolerance. Here, we propose and experimentally demonstrate a scalable method to generate optical non-Gaussian states with a resonator-based quantum memory that supports continuous-time storage and retrieval, in contrast to conventional loop-based memories. We introduce a dual-mode operation of the memory, enabling both storage and entangling functionalities within a single device. By employing a time-domain-multiplexed approach, we successfully demonstrate both cat and Gottesman-Kitaev-Preskill (GKP) breeding protocols in a scalable fashion, marking a key step toward quantum error correction. Our experiment also marks the first full demonstration of an optical resonator memory performing writing, storage, and readout operations. We validate the memory by storing squeezed single-photon states with up to 93% total efficiency, and measure an energy relaxation time $T_1 =$2.3$\mu$s and dephasing time $T_{\phi} =$0.96$\mu$s. These results establish a scalable pathway to generating complex non-Gaussian states required for fault-tolerant optical quantum computing. Beyond computation, our techniques provide new tools for enhancing quantum communication, sensing, and metrology.