## "Monopole harmonic superconductivity"

**Speaker:**Yi Li, Johns Hopkins University

**When:**April 23, 2018 (Mon), 11:00AM to 12:00PM (add to my calendar)

**Location:**SCI 328

**Hosted by:**Anushya Chandran

*This event is part of the Condensed Matter Theory Seminar Series. *

In this talk, I will present a dramatic effect of Fermi surface monopole structure on superconducting pairing symmetry: When Cooper pairs acquire non-trivial two-particle Berry phases, their pairing phases cannot be globally well-defined in the momentum space. Therefore, the conventional description of superconducting pairing symmetries in terms of spherical harmonics (e.g. s-, p-, d-waves) ceases to apply. Instead, they are represented by monopole harmonic functions. These novel superconducting states can be realized in doped Weyl semi-metals. They exhibit topologically protected nodal gap functions and rich patterns of Majorana surface arcs regardless of concrete pairing mechanism.