The Search for Topological Phases of Matter
Ashley Cook is a postdoctoral researcher in condensed matter theory in the group of Prof. Joel Moore at UC Berkeley.
Abstract: In our daily lives, we encounter phases of matter distinguished by the symmetries they break, such as steam and ice. Such phases are well-understood with very established theory of Ginzburg and Landau, suggesting the work to characterize and understand phases of matter might be close to completion. In the 1980's, however, physicists were confronted with the integer and fractional quantum Hall effects, phases of matter that cannot be distinguished from one another by symmetry-breaking. Instead, these phases are distinguished by topological invariants: they display signatures that are unaffected by sufficiently small perturbations (topological signatures), that we can measure with remarkable accuracy. In the intervening decades, the set of topological phases of matter has expanded dramatically, with tremendous potential for applications from table-top study of high-energy physics to topologically-protected quantum computation. Considerable work remains, however, not just to understand the topological phases we have already found, but in simply finding the rest! In this talk, I will discuss some recently-discovered topological phases of matter, the magnetic topological Kondo semimetal phases, the higher-order topological phases, and the topological skyrmion phases, to introduce this wide-ranging and increasingly important field of research.