Physics at the Falls: Pairing Phenomena from Neutron Stars to Cold Atoms
State University of New York at Buffalo
Speaker: J. A. Sauls
Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208
March 24, 2016
Abstract: The superfluid phases of 3He are a paradigm for spontaneous symmetry breaking in quantum field theory and condensed matter physics. Recent developments in condensed matter physics emphasize a new organizing principle based on topology. A frontier in condensed matter physics is the theoretical classification, experimental detection and characterization of exotic edge excitations - Majorana and Weyl fermions - that are signatures of topological order. I discuss signatures of broken space-time symmetries - rotations, parity and time-reversal (BTRS) - and their connections with topological order for the ground-states of superfluid 3He, Sr2RuO4 and UPt3 . I highlight recent experimental observations of BTRS in the heavy fermion superconductor UPt3 and the chiral A-phase of 3He. The former is the observation of an optical polar Kerr effect , while the latter is based on the measurement of an anomalous Hall effect for negative ions in 3He-A . I outline a theory of the anomalous Hall mobility of electrons in 3He-A, and show that the experimental results provide a direct observation of Weyl Fermions and topological order in 3He-A.
Research supported by National Science Foundation Grant: DMR-1508730.
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