QuIC - TaQS: Interconnects for a Superconducting-Atomic Hybrid Quantum Network

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

A currently envisioned ‘quantum internet’ infrastructure consists of linked quantum devices, such as quantum computers, simulators, and sensors, that may be located in widely separated geographical locations. Distributing quantum information between these devices will be key for utilizing them with a technological advantage over classical information technologies, and making the accessible to a wide range of researchers and commercial users. The goal of this research program is the development and demonstration of essential interconnect technologies that together enable long-range links between widely separated quantum computing nodes. Specifically, three interconnects are developed: First, a frequency converter that converts quantum signals from cryogenically operated solid-state qubits to optical signals that can be sent through fiber networks. Second, a repeater device that can extend the range of optical quantum signals transmitted. And finally, a solid-state memory for cryogenic qubits that will allow tolerating latencies in large-scale networks. Together, the realization of these interconnect technologies are a critical stepping stone for establishing long-distance connections between quantum devices. As part of the project, the PIs are developing educational and outreach programs on the topic of quantum engineering and quantum networking, and are collaborating with industry and national lab partners. The research project targets three distinct and complementary quantum interconnection schemes that are tackled with a joint theoretical and experimental effort. Microwave-to-optical conversion is crucial for transmitting quantum states originating from superconducting qubits over large distances at non-cryogenic temperatures. To that end, superconducting quantum circuits are interfaced with optomechanical crystals that can couple microwave radiation to optical light in the telecom band. The radiation emitted by this converter system can be interfaced with optical photons emitted by Yb atoms through quantum interference. Arrays of Yb atoms are a promising platform for atomic quantum information processing and will be used to realize a quantum repeater. The third interconnect is between superconducting qubits and rare-earth ion spins in doped crystals. Such spins are a promising resource for realizing ultra-long coherence times in the microwave domain. Because optical conversion as well as quantum interference schemes are highly probabilistic, very good quantum memory is required to tolerate the resulting latency in a network. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.