Editor’s Series Webinar—Quantum Focus, Session 2 of 3

Strongly correlated quantum materials, such as high-temperature superconductors, hold great promise for driving future technological advances. The fermionic Hubbard model (FHM), which describes fermion correlations in a lattice, is considered one of the key models for understanding high-temperature superconductors. Yet, resolving its low-temperature phase diagram remains difficult, both theoretically and numerically.

Ultracold fermionic atoms in optical lattices offer a clean and highly controllable platform to emulate the FHM. In this webinar, I will present our recent progress in quantum simulations of the FHM. We have realized a large, homogeneous Hubbard system with about 800,000 lattice sites—roughly 10,000 times larger than those in previous studies—and reached temperatures below the Néel temperature. By analyzing interference patterns of lattice fermions, we extracted short-range correlations and revealed non-zero coherence even in the Mott insulating regime, indicating strong underlying antiferromagnetic correlations. Building on this, we directly probed antiferromagnetic correlations using spin-sensitive Bragg scattering and observed a critical enhancement of the spin structure factor consistent with a power-law divergence, providing compelling evidence for the realization of the antiferromagnetic phase transition.

These results mark an important milestone toward exploring the exotic low-temperature phases expected in the FHM—such as pseudogap behavior, stripe order, and d-wave superfluidity—in the quest to understand high-temperature superconductivity.

Key Learnings for Attendees:

• Key methods for realizing a homogeneous Fermi–Hubbard quantum simulator at low temperature.
• How interference patterns reveal short-range coherence and correlations of lattice fermions.
• How spin-sensitive Bragg measurements identify the antiferromagnetic phase transition.
• Experimental advances enabling precise control and correlation measurements in quantum simulators.

Who Should Attend:

• Atomic, molecular, and optical physicists
• Condensed matter and quantum materials researchers
• Quantum simulation and quantum computing scientists and engineers
• Experimental and theoretical physicists studying strongly correlated systems
• Optical and quantum control engineers working with cold-atom or ion-trap platforms
• Graduate students and early-career researchers in quantum science and engineering

About the PT Editor’s Series:

The Editor’s Series of webinars runs throughout the year and comprises a range of popular topics hand-selected by the PT editorial team based on their alignment with our audience’s diverse interests. Stay subscribed to our emails to hear about future events on different topical areas.