Signatures of Weyl-Majorana Excitations in Superfluid 3He

Invited Talk, LT28, Gothenburg Sweden, 2017

Authors: J. A. Sauls
Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208
August 15, 2017

Abstract: I discuss the relationship between broken symmetries and topology of the chiral ground state of superfluid 3He-A and the Fermionic states confined near surfaces, domain walls and mesoscopic defects. The low-energy Fermionic spectrum of thin films of 3He-A contains a branch of chiral edge states (Majorana-Weyl Fermions). The chiral vacuum hosts a mass current confined near the edge boundaries. For translationally invariant confining boundaries the vacuum edge current is given by J = n3 ħ/4, where n3 is particle density of bulk 3He. I will highlight several results: (i) the connection between the Majorana-Weyl spectrum on the edge and the chiral vacuum, (ii) the absence of topological protection of the vacuum edge current to symmetry breaking perturbations, (iii) the effects of hybridization of spatially separated Majorana-Weyl Fermions under lateral confinement, and (iv) their experimental signatures in heat and mass transport, as well as ion mobility experiments.

This research was supported by U.S. National Science Foundation Grant: DMR-1508730.

Slides: [PDF]

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