Chicago retreat brings together HQAN researchers from across Midwestern quantum ecosystem

Last week, HQAN faculty and student researchers met up in Chicago for the Annual Retreat of HQAN (Hybrid Quantum Architectures and Networks), an NSF-QLCI center. The event showcased recent HQAN advances in realizing quantum computing architectures and networks and provided an occasion to discuss the center’s strategy as it ends the fourth year of research, outreach, and workforce development efforts.

HQAN is a National Science Foundation (NSF) Quantum Leap Challenge Institute (QLCI) shared between the University of Illinois, the University of Wisconsin and the University of Chicago. As one of the initial three QLCIs launched across the country in 2020 (followed by two additional QLCIs launched in 2021), the NSF established HQAN to address a “specific, well-defined and compelling challenge” aligned with the goals of the National Quantum Initiative.

“HQAN's goals are to create scalability [for quantum networks] due to our non-monolithic approach, involving modular, heterogeneous machines. The result is distributed quantum computing,” said Brian DeMarco, HQAN Director and Professor of Physics and IQUIST Director at Illinois, during his opening address.

HQAN accomplishes these goals by structuring its research efforts into three Major Activities (MAs) with an added outreach and workforce development component. The three groups work independently, though in support of one another, and the first half of the day’s events showcased their recent achievements.

The different MA leads touched upon various highlights during their presentations, including some of the 51 publications HQAN has produced in its four years and unpublished work (including 16 current preprint articles).

MA1 co-leads Hannes Bernien, Assistant Professor of Molecular Engineering at the University of Chicago, and Mark Saffman, Johannes Rydberg Professor at the University of Wisconsin and Wisconsin Quantum Institute Director, highlighted several projects across the various quantum computing platforms worked on by the center’s researchers. Examples given included manipulating neutral atoms in the Saffman group, integrating a nanophotonic chip platform with neutral atoms in the Bernien group, and advancements in building and now using a trapped ion testbed at the University of Illinois shared by the Covey, DeMarco and Goldschmidt groups.

MA2 co-lead Eric Chitambar, Associate Professor of Electrical and Computer Engineering at the University of Illinois, spoke about HQAN’s efforts to certify and measure “quantum-ness”, as well tools for practical distributed and heterogenous computation, and quantum protocols. This activity has resulted in three new collaborations that were not part of the original HQAN scope. Among the research done in this area is collaborate work, including Illinois Associate Professor of Physics Bryan Clark on how to more efficiently prepare matrix product states and a collaboration between the groups of Chitambar and Illinois Assistant Professor of Physics and HQAN co-principal investigator Elizabeth Goldschmidt on generating graph states using a heralded scheme.

Chitambar also spoke of the recent success of a collaboration between his group and that of University of Chicago John A. MacLean Sr. Professor of Molecular Engineering Innovation and Enterprise Andrew Cleland. The collaboration implements a quantum secret sharing protocol that requires the genuine three-party entanglement present in the superconductor quantum testbed of the Cleland group.

Next, Angela Kou, Illinois Assistant Professor of Physics and MA3 co-lead, spoke about developments in the third strain of HQAN quantum research. This activity aims to build protected quantum nodes that can be used for distributed processing, and can be relied upon to individually secure any quantum information.

“A surface code, another approach to implementing secure and reliable quantum protocols, requires a lot of qubits for exponentially fewer actual “logical” qubits to be realized. The complementary approach is using protected qubits which have exponential insensitivity to both bit-flip and phase-flip errors,” said Kou.

One of the developments highlighted included work by the group of Robert McDermott, the University of Wisconsin Roeske Professor of Physics and HQAN MA3 co-lead. Their superconductor qubits exhibit long lifetimes and can be assembled to form a single protected qubit.

Another large HQAN effort encourages a quantum-savvy population through workforce development and public outreach efforts. Jennifer Choy, Assistant Professor of Electrical and Computer Engineering at the University of Wisconsin, leads these efforts for the center and spoke to attendees about the outcomes of various programs. One of them is TeachQuantum, a program that trains school teachers to bring quantum concepts into the classroom. Outreach program manager Sarah Parker addressed Wonders of Quantum Physics, which provides quantum activity kits for students of various ages.

Sarah Parker led a brainstorming session where HQAN students and faculty discussed new ideas for the aforementioned quantum activity kits. They also met with Ezekiel Burts III, the Director of Duality, a quantum start-up incubator. There were many questions for “Eze” about what it takes to make a quantum start-up successful and about Duality’s ambitious future projects which intend to make lab space available to their companies.

The concluding poster session and reception allowed HQAN students, faculty, and staff to relax and enjoy everyone's company more informally. Allowing students and faculty from across institutions to strengthen and form new friendships, socialize, and discuss life more broadly outside of research is a critical aspect of a center that's distributed across these three Midwest quantum computing research powerhouses. As it enters its fifth and final year of initial funding, HQAN promises steady progress toward realizing quantum computing architectures and networks