Talk by Dr. Anton Vorontsov (Physics Department, MSU)

11/25/2019  Wilson Hall 1-144  4:10-5:00pm


Properties of materials, of elementary particles and even cosmological states of the Universe, are closely tied to the concept of `broken symmetry'.  Superconductivity is one of the exotic states that can be seen as a special liquid made from many interacting electrons inside a metal. Once set in motion, this liquid can flow without energy dissipation, and thus without slowing down, forever. From a physical and mathematical viewpoint, the origin of the superconducting state lies in broken symmetry of the quantum-mechanical wavefunction of the superconducting condensate. In this case it will have the same phase everywhere in the metal.  One of the most interesting questions that one may ask is whether the superconducting liquid can break other symmetries simultaneously, and thus have signatures of multiple states of matter?  In this talk I will give an introduction to the phenomenon of superconductivity, and show how a new spatial pattern can arise in the phase of the complex field of the superconducting order parameter. The periodic pattern breaks continuous translations, reducing symmetry to that of a crystal and showing unusual structure in the superflow field. This new ground state is defined by cells of spontaneous persistent current loops that lower energy,
instead of increasing it.