Scalable Optical Links for Controlling Bosonic Quantum Processors

TL;DR

This paper demonstrates scalable optical control of a bosonic quantum processor, enabling high-fidelity operations over long distances, which is crucial for advancing large-scale superconducting quantum computers.

Contribution

It introduces an optical control method for bosonic quantum processors, achieving universal operations, long-distance transmission, and multi-channel control at cryogenic temperatures.

Findings

Controlled Fock states with up to ten photons.

Remote control over 15 km with >95% fidelity.

Scalable architecture for distributed quantum data centers.

Abstract

Superconducting quantum computing has the potential to revolutionize computational capabilities. However, scaling up large quantum processors is limited by the cumbersome and heat-conductive electronic cables that connect room-temperature control electronics to quantum processors, leading to significant signal attenuation. Optical fibers provide a promising solution, but their use has been restricted to controlling simple two-level quantum systems over short distances. Here, we demonstrate optical control of a bosonic quantum processor, achieving universal operations on the joint Hilbert space of a transmon qubit and a storage cavity. Using an array of cryogenic fiber-integrated uni-traveling-carrier photodiodes, we prepare Fock states containing up to ten photons. Additionally, remote control of bosonic modes over a transmission distance of 15 km has been achieved, with fidelities exceeding 95%. The combination of high-dimensional quantum control, multi-channel operation, and long-distance transmission addresses the key requirements for scaling superconducting quantum computers and enables architectures for distributed quantum data centers.