Too Frustrated to Order: The Tale of Quantum Spin Liquids

Magnetism, first encountered by humans in naturally occurring lodestones, remains one of the most intriguing phenomena in physics. Even with Maxwell’s unification of electricity and magnetism, the behavior of magnetism inside materials still holds mysteries. When certain magnets are cooled to near absolute zero, quantum mechanics takes over, and entirely new states of matter can emerge. Here, spins face a frustrating dilemma: multiple lowest-energy arrangements exist, and no single one can be chosen. This allows quantum fluctuations to take hold and give rise to an exotic state of matter -- the quantum spin liquid. The world inside a quantum spin liquid defies intuition; spins no longer act as individuals - all spins within the material ebb and flow together like a liquid, exotic particles called “spinons” emerge, and the system becomes resilient to external disturbances. In my talk, I will explain the history of quantum spin liquids, how they are measured, and why, despite decades of searching, a definitive quantum spin liquid remains the holy grail for research in quantum magnetism.

Dr. Gavin Hester is an Assistant Professor in the Department of Physics at Brock University. He joined Brock University in 2023, following a postdoctoral position at Purdue University where he started a crystal growth laboratory and led neutron scattering experiments on quantum magnets. He received his PhD from Colorado State University in 2021 studying rare-earth pyrosilicates, a family of quantum magnets. He began his journey in physics at Missouri State University, earning his Bachelor of Science in Physics 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 the search for quantum magnetic states in the presence of disorder. He has a passion for explaining and teaching physics, particularly about the wonderfully weird world of quantum mechanics.