QuIC-TAQS: Deterministically Placed Nuclear Spin Quantum Memories for Entanglement Distribution

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

Connecting nodes of a communication network with quantum states would fundamentally change the way we communicate, process information, and sense the world around us. Unfortunately, realizing such connections over long distances has been hampered by the lack of quantum interconnects that can transfer, store, and manipulate delicate quantum states. This project aims to demonstrate a quantum repeater with precisely placed quantum memory to enable large-scale quantum networks. The PIs will accomplish this using ultra-pure semiconductor materials coupled with novel atomic-scale fabrication techniques capable of creating quantum devices with atomic precision. The devices will be integrated into photonic platforms and protocols for their use and system-level integration will be developed. The regularity and quality of the qubits synthesized through these techniques will enable large-scale quantum interconnects. The PIs will also develop new multi-disciplinary undergraduate curricula to train students in quantum information science and recruit students from underrepresented groups into the program and research. Ensuring quantum concepts are introduced during the first year of study coupled with hands-on undergraduate research will help train the future workforce in quantum information sciences. This research aims to demonstrate a quantum repeater using the silicon monovacancy at a hexagonal Si site (the V1 center) in isotopically purified SiC. The goals of this research include: (1) create deterministically-placed V1 centers in ultra-low defect, isotopically-pure 28Si12C grown epitaxially; (2) create nearby deterministically-placed 29Si or 13C nuclear isotopes as quantum memories using atomically precise fabrication techniques using a scanning tunneling microscope; (3) exploit the precise placement of the nuclear spin to enable superior quantum memories and control schemes for transferring quantum information to and from the memory and distant nodes; (4) integrate the optically-addressable defects and quantum memories into nanophotonic structures, providing a nanophotonic interface and aiding integration in scalable quantum networks; and (5) develop and implement optimized routing, entanglement, and measurement protocols for the demonstrated repeater in a quantum internet, incorporating realistic device performance such as gate errors, channel loss, and memory lifetimes. The results of this project will enable the fabrication of quantum repeaters on the timescale of days compared to the year that current approaches require. Additionally, the utility of this approach is not limited to developing quantum repeaters, and could enable superior defect-based quantum processors, quantum sub-systems, and quantum sensors. 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.