Conférence du vendredi 2 octobre 2026

When Magnets Get Frustrated: The Search for Quantum Spin Liquids - Gavin Hester (Brock University)

Abstract: Magnetism, first encountered by humans thousands of years ago in naturally occurring lodestones, remains one of the most intriguing phenomena in physics. As physicists, we have learned that electricity and magnetism can be described by Maxwell’s equations. Yet the behavior of magnetism inside materials remains surprisingly difficult to understand. In the past 60 years, we have found that when some magnetic materials are cooled close to absolute zero, the rules of quantum mechanics can lead to behavior with no analogue in our everyday world.

One particularly interesting situation occurs when the magnetic atoms in a material cannot simultaneously satisfy all of their preferred interactions. This “magnetic frustration” can prevent the spins from settling into an ordered arrangement, allowing quantum fluctuations to dominate instead. In extreme cases, this can produce a quantum spin liquid: an unusual state of matter in which the magnetic moments remain dynamic even at temperatures approaching absolute zero and can give rise to entirely new collective phenomena.

In this talk, I will introduce how physicists design, synthesize, and study quantum magnetic materials, and how experiments using techniques such as neutron scattering allow us to peer inside of materials to see what their spins are doing at the atomic scale. I will discuss the decades-long search for quantum spin liquids, why identifying one experimentally has proven so difficult, and how the search continues to uncover unexpected physics in new materials.

Bio: Dr. Gavin Hester is an Assistant Professor in the Department of Physics at Brock University. He joined Brock University in 2023, following a postdoctoral researcher position at Purdue University under the supervision of Prof. Arnab Banerjee and Prof. Yong Chen. He received his PhD. from Colorado State University in 2021 while working with Prof. Kate Ross. He received his Bachelor of Science in Physics from Missouri State University in 2016. His research focuses on the study of quantum magnetic materials using a wide variety of neutron and x-ray scattering techniques. Recently, his research has centered on understanding how disorder influences the ground state of many-body quantum systems.