Order without symmetry breaking
The importance of symmetry in physics can be motivated by Noether’s theorem which states a symmetry of a system must lead to a conserved quantity. Physics, and in particular condensed matter physics, has historically been focused on the discovery of new transitions and phases based on bulk broken symmetries. Examples include the discovery of ferroelectricity (used in transducers), ferromagnetism (magnets), and also superconductors. However, as highlighted by the recent 2016 Nobel Prize, new states of matter and novel properties can occur near surfaces and boundaries in materials where no bulk symmetry breaking occurs. Examples include the quantum hall effect and topological insulators where electrons can flow unimpeded near the surface of a material analogous to superconductivity. Model magnets have played a central part in testing the theories which have provided the basis for understanding topology in materials. In this talk, I will discuss the importance of topology and note its link to model magnetic spin chains studied using neutron scattering. I will then outline recent results on classical model magnets testing some of these ideas and illustrating the presence of new states and properties that can exist near boundaries or edges in materials.
All Welcome and Undergraduates are encouraged to attend.
Tea and cakes will be served from 1630 outside Lecture Theatre A.
Our General Interest Seminars are an opportunity for distinguished speakers to present new research in physics and related areas. The material presented is suitable for undergraduate level upwards and all members of the School are welcome to attend..