Excitations,Topological Defects and Collective Modes in Unconventional Superconductors and Superfluid 3He

Nordic Institute for Theoretical Physics

Speaker: J. A. Sauls
Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208
January 28, 2011

Abstract: I present an overview of theoretical ideas and predictions of topological defects, vortices and domain walls in superfluid mixtures with broken U(1) × U(1) symmetry, as well as spin-triplet, chiral superconductors and superfluids: 3He-A, Sr2RuO4 and UPt3. I then describe recent theoretical work on the structure and dynamics of vortices, mesoscopic defects and composite mass/charge and spin vortices embedded in chiral p-wave superconductors. Chiral, spin-triplet superfluids and superconductors are shown (i) to have two distinct types of singly quantized vortices associated with the chiral ground state with broken time-reversal symmetry, (ii) stable doubly quantized vortex states over a wide range of field and temperature and (iii) unique magnetic defects that are closely related to chiral edge currents in the Meissner state. Topologically defects that involve the interplay between different components of the spin-triplet condensate are also possible. I describe the connection between fractionally quantized flux lines in superconducting mixtures and the 1/2 quantum vortex-spin-disgyration in chiral, spin-triplet superconductors and superfluid films of 3He-A. These topological defects and vortex lattice structures provide fingerprints of broken time-reversal symmetry as well as novel signatures of spin-triplet pairing in superfluid films of 3He-A and possible realizations of odd-parity, spin-triplet pairing in superconductors such as Sr2RuO4 and UPt3.

This research was supported by NSF Grant: DMR-0805277

Slides: [PDF]

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