Boston College physicists led an inter-disciplinary team that discovered a new particle or previously undetectable quantum exccitation. This is known as the axial Higgs mod, which is a magnetic relative to the mass-defining Higgs Boson particle. The team reported in the online edition Nature.
Understanding mass was made possible by the discovery of the long-sought Higgs Boson a decade ago. The axial Higgs mode, unlike its parent, has a magnetic moment. This requires a more complicated form of the theory to explain the properties of its properties, according to Kenneth Burch of Boston College Physics, a co-author of “Axial Higgs Modified by Quantum Pathway Interferences in RTe3”.
Burch stated that theories that predicted such a mode existed have been used to explain “dark material,” the almost invisible material that makes up most of the universe but which only shows itself through gravity.
Higgs Boson was discovered by experiments in a massive particle collision. The team instead focused on RTe3, or rare earth tritelluride. This well-studiedquantum material can be examined at room temperatures in a “tabletop” experimental format.
Burch stated, “It’s not everyday you find a new particle on your tabletop.”
Burch stated that RTe3 exhibits properties similar to the theory that generates the axial Higgs mode. He said that the main problem in finding Higgs particles is their weak coupling with experimental probes such as beams light. Similar to the previous example, it is often difficult to reveal subtle quantum properties of particles using complex experimental setups such as large magnets and powerful lasers while also cooling samples to extreme cold temperatures.
These challenges were overcome by the team’s unique use of scattering light and the right choice of quantum simulator. This material is essentially a material that mimics the properties of the study.
Burch stated that the researchers were focusing on a compound with a long-standing reputation for having a “charge densitywave”, which is a state in which electrons self-organize and have a periodic density in space.
He added that the fundamental theory of this wave is similar to components of the standard model for particle physics. The charge density wave in this instance is very special. It emerges at far beyond room temperature and involves modulation both of the charge density as well as the atomic orbits. This allows the Higgs Boson that is associated with this charge density wave to include additional components such as axial, which means it may contain angular momentum.
Burch explained that light scattering was used by the team to reveal the subtle nature and subtleties of the mode. This involves shining a laser on the material which can change the color as well as the polarization. The Higgs Boson is created by the light, and the color change results in polarization.
The particle can also be made with other components if the outgoing and incident polarizations are chosen correctly. For example, one component could be missing magnetism or pointing up. They used quantum mechanics’ fundamental principle that components cancel in one configuration. They can however add to a different configuration.
Burch stated, “As such we were able reveal the hidden magnet component and prove that the discovery of the first-axial Higgs mode was made.”
Burch stated that the detection of an axial Higgs was predicted by high-energy particle Physics to explain dark matter. It has not been seen. Its discovery in a condensed material system was completely unexpected and marks the beginning of a new broken state. This was not done in extreme conditions that are required to observe new particles. It was performed at room temperature using a tabletop experiment. We were able to achieve quantum control by changing the polarization.
Burch stated that the simple and accessible experimental methods used by the team could be applied to other areas.
Burch stated that many of these experiments were carried out by undergraduates in my laboratory. The approach can be applied directly to many collective phenomena, including superconductors and magnets as well as charge density waves. We also bring quantum interference in materials with topological and/or correlated phases to room temperature, thereby avoiding the difficulties of extreme experimental conditions.
Burch was not the only co-author of the report. Boston College also had Grant McNamara (undergraduate student), Yiping Wang (post-doctoral researcher), and Md Mofazzel Hosen (post-doctoral researcher). Burch stated that Wang was awarded the American Physical Society’s Best Dissertation in Magnetism for her contribution to the project.
Burch stated that it was important to use the wide range of expertise from researchers from BC, Harvard University and Princeton University, as well as the University of Massachusetts Amherst. Yale University, University of Washington and the Chinese Academy of Sciences.
Burch stated, “This is a testament to the power of interdisciplinarity in discovering and controlling new phenomena.” It’s not often that you can combine optics, chemistry and physical theory in one project.
