NSF-BSF: The Phase-Modulated Quantum Optical Frequency Comb: A Simple Platform for One-Way Quantum Computing

This joint project, ''NSF-BSF: The phase-modulated quantum optical frequency comb: a platform for one-way quantum computing,'' is a collaboration between the research groups of Olivier Pfister at the University of Virginia and Avi Pe'er at Bar-Ilan University, supported by the National Science Foundation (NSF) and the US-Israel Binational Science Foundation (BSF) Collaborative Research Opportunities program. Quantum computing is now in a "Moon race," supported by the National Quantum Initiative, to harness the extraordinary computational power of quantum physical systems for specific intractable problems such as integer factoring (relevant to cryptography and national security), discovering carbon sequestration processes, or discovering efficient nitrogen fixation processes for fertilizer production.

One of the challenges to building a quantum computer is scalability. The Pfister-Pe’er collaboration leverages the outstanding scalability of frequency-multiplexed photonic quantum computing, invented by Pfister, by associating it with the ultrabroadband quantum detector technology invented by Pe’er.

The goal of this project is to demonstrate a large-scale photonic quantum computer by use of quantum frequency multiplexing or "quantum bandwidth," the quantum analogue of the technology subtending FM radio and broadband wireless. The core system is the optical frequency comb (OFC) defined by the resonant modes of an optical cavity. The OFC has seen spectacular development since its Nobel-recognized inception by T.W.

Hänsch and J.L. Hall, with applications such as ultimate precision metrology and fundamental measurements. Pfister's group was the first to experimentally demonstrate that the quantum OFC emitted by a single optical parametric oscillator (OPO) is a quantum computing substrate, by generating scalable cluster-state entanglement between the ''teeth'' of the QOFC.

In parallel, Pe'er's group demonstrated a novel quantum detection method, parametric homodyne detection (PHD), that is broadband and resilient to losses. The project will bring both technologies together to demonstrate bona fide quantum processing in the quantum OFC and scale quantum computing beyond the noisy, intermediate-size quantum (NISQ) regime.

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.