A groundbreaking discovery has revealed the existence of graviton-like particles showing specific rotational behavior in a special type of material known as fractional quantum Hall liquids. This finding by scientists including Professor Kun Yang at Florida State University, represents a major leap in understanding these unique states of matter. Summarized by Professor Yang in a commentarypublished in The Innovation, these strange particles behave similarly to theoretical particles called gravitons, which are part of certain gravity models.
These quantum Hall liquids are intriguing because they maintain their unusual properties even when disturbed. However, a key insight showed that the standard way of explaining these properties left out an important geometric element. This discovery led researchers to identify large-scale movements in the structure of these liquids, which act like vibrations in the material’s shape. What’s fascinating is that these vibrations mirror the behavior of gravitons, the particles thought to be linked to the force of gravity.
Through detailed studies, the researchers confirmed the presence of these graviton-like particles and, more importantly, uncovered their specific spinning behavior, known as chirality. Chirality refers to the way something rotates, either clockwise or counterclockwise, and in this case, the particles displayed distinct chiral behavior based on the type of liquid they emerged from. As Professor Yang explains, “These graviton-like particles represent a unique aspect of the geometry within fractional quantum Hall states, offering a fresh perspective on their complex nature.”
A major breakthrough occurred when a team led by Prof. Yang described how a specific technique called Raman scattering, which uses polarized light, could detect these particles. Raman scattering is a process where light is absorbed and then emitted in a way that reveals the energy and spin of these particles. Earlier attempts to capture this behavior, decades ago, fell short due to outdated methods. Modern tools, however, have made it possible. Although the project encountered delays after the passing of a key researcher, other colleagues continued the work and ultimately confirmed the presence and behavior of these graviton-like particles, pushing forward both condensed matter physics and the broader study of gravity.
This discovery holds tremendous significance. It may be the first time such a graviton-like particle, with specific spinning characteristics, has been observed in a physical system. While the actual gravitons thought to be involved in gravitational waves are still theoretical, this observation provides a powerful analogy. Quasiparticles, which are the name given to these excitations in materials, are somewhat like real particles but exist only under particular conditions. Most quasiparticles have much simpler traits, making the discovery of one with such a unique spin especially important. As Professor Yang emphasized, “These graviton-like particles don’t just happen by chance; they provide a new way to study the deeper structure and geometry of quantum Hall systems.”
The research also offers new paths for investigating these complex materials. Traditional methods tend to focus on the edges of the systems, which can be difficult to interpret because of various complicated factors. The new Raman scattering approach looks directly into the interior of the material, offering a much clearer view. This method could also help scientists explore certain types of fractional quantum Hall liquids that may eventually lead to breakthroughs in advanced quantum computing.
The connection between these graviton-like particles and real gravitons, which are linked to the force of gravity, goes beyond just a metaphor. Both areas of research—condensed matter and gravity—use similar mathematical models, especially when studying fewer dimensions. Although the “gravitons” found in these systems aren’t the same as those predicted by Einstein’s theory of gravity, they share enough similarities to encourage greater collaboration between scientists in these fields. Yang and his team believe that by exploring these connections further, we may unlock new insights into both the nature of matter and the forces shaping the universe.
This discovery represents a major advance in understanding intricate states of matter and paves the way for exciting new research opportunities. As scientists continue to delve deeper into these graviton-like particles, we may gain a clearer understanding of the universe’s fundamental structure and the forces that govern it.
Journal Reference
Yang, Kun. “Graviton-like excitation observed with predicted chirality in fractional quantum Hall liquids.” The Innovation, 2024. DOI: https://doi.org/10.1016/j.xinn.2024.100641
About the Author
Dr. Kun Yang (杨昆) is McKenzie Professor of Physics at Florida State University, and also an affiliated member of National High Magnetic Field Lab in Tallahassee, Florida, USA. He received his Ph.D. from Indiana University in 1994. After postdoctoral work in Princeton and Caltech, he joined the faculty of Florida State University in 1999. His research interest is in theoretical condensed matter and statistical physics. The honors and awards he received over the years include Alfred Sloan fellowship in 1999, Outstanding Young Researcher award of Overseas Chinese Physics Association in 2004, and Outstanding Referee award of American Physical Society (APS) in 2015. He was elected fellow of American Physical Society in 2011, and fellow of American Association for Advancement of Science (AAAS) in 2016.
杨昆博士1989年本科毕业于复旦大学物理系，随后经CUSPEA项目赴美，于1994年获印地安那大学博士学位。之后在普林斯顿大学及加州理工学院从事博士后研究工作。1999年起在佛罗里达州立大学任教，现担任McKenzie讲座教授。曾获得斯隆研究奖，海外华人物理学会青年研究奖等荣誉，并当选美国物理学会和美国科学促进会会士。
