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Institute for Condensed Matter Theory Seminar: "Monopole Harmonic Ordering"

Event Type
Physics Department
190 ESB
Feb 11, 2019   12:00 pm  
Yi Li, John Hopkins University
Originating Calendar
Physics - Institute for Condensed Matter Theory Seminar

One interesting question in interacting topological phases is how to characterize and reveal new topological properties in many-body states arising from interactions. In the search for a full answer, in this talk, I will introduce the monopole harmonic ordering in many-body topological states. This new class of three-dimensional topological many-body ordering states is characterized by a generalized Berry phase and monopole harmonic symmetries. Examples of monopole harmonic superconductivity and monopole harmonic density-wave states as well as their potentially realizations in doped Weyl semimetals will be discussed.  The particle-particle (Cooper) pairing, or, the particle-hole pairing in these monopole harmonic ordering states inherit non-trivial Berry phases from Fermi surface topology. Their gap functions cannot be globally well-defined in momentum space, and hence go beyond standard symmetry classes based on spherical harmonics. Consequently, they exhibit topologically protected nodal structures regardless of specific ordering mechanism. 

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