DOE's quantum center SQMS Renewal Fuels UMN's Hunt for Dark Photons

The U.S. Department of Energy (DOE) has announced a $125 million, five-year renewal for the Superconducting Quantum Materials and Systems (SQMS) Center, a national research center led by DOE's Fermilab. As a partner of the SQMS center since 2021, the University of Minnesota will play a critical, ongoing role in leveraging the center's cutting-edge technology to search for new discoveries in fundamental physics.

The SQMS Center is one of five DOE National Quantum Information Science Research Centers established to ensure the U.S. remains a global leader in quantum computing, sensing and communication.

UMN’s Role: Pioneering Quantum Sensing

The University of Minnesota group, led by Zhen Liu, a professor in the School of Physics and Astronomy, is driving the theoretical and analytical framework for the quantum sensing program's flagship "Dark SRF" experiment. This experiment uses the center’s high-quality superconducting radiofrequency (SRF) cavities—technologies originally developed for particle accelerators—to hunt for elusive hypothetical particles, such as dark photons.

"Our team at the UMN focuses on developing the theory, experimental protocols, and data analysis strategies for these ultra-sensitive experiments," said Zhen Liu, UMN's lead principal investigator for the center.

This UMN-led work has already produced significant, world-leading results, including:

• A landmark 2023 publication in Physical Review Letters, "Search for Dark Photons with Superconducting Radio Frequency Cavities," featured in a Fermilab news release.
• Recent theoretical work on "Modeling frequency instability in high-quality resonant experiments(under peer review)" enabled "Improved Dark Photon Sensitivity from the Dark SRF Experiment (under peer review)," which now provides the best laboratory-based constraints on the mass of the photon.
• Novel proposals for dark matter detection using magnetically levitated sensors, detailed in Physical Review D publications on "Maglev for dark matter" and "Ultralight dark matter detection with levitated ferromagnets."
   

"The initial five years of SQMS were incredibly successful, and this renewal is a tremendous vote of confidence from the DOE," said Zhen Liu. "At UMN, we are leveraging the unparalleled sensitivity of SQMS's technologies to search for new physics. This continued partnership not only advances fundamental science but also solidifies Minnesota's role in interdisciplinary research in high-energy physics, material science, and quantum information science."

The SQMS 2.0 Vision

The SQMS Center's first five years produced major advances, including demonstrating novel materials that led to a 2.5-times improvement in the error performance of some quantum systems and developing new cryogenic technologies to help scale up quantum computers.

The next phase, "SQMS 2.0," will focus on developing and deploying beyond-state-of-the-art quantum systems. Key goals include:

• Developing a 100-plus-qudit quantum processor: This 3D cavity-based system will have a computational space equivalent to roughly 500 two-level qubits.
• Achieving chip-based breakthroughs: The center will pursue new materials to reach an ambitious goal of 10-millisecond coherence in superconducting qubits.
• Prototyping a quantum data-center unit: This will build the scalable cryogenic and microwave infrastructure needed for future quantum networks.
   

The SQMS collaboration, which unites 36 partners from national labs, universities, and industry, is foundational to U.S. competitiveness in quantum technology. By bridging the gap between fundamental science and engineering, the center is creating a path toward a future quantum internet and quantum-centric supercomputing.