Time: 09:30 am (UTC/GMT+08:00, Beijing/Shanghai), Jun. 10 (Wedn.), 2020

Online Meeting Room (zoom.com):  Click here to join the meeting

Meeting ID:  932 5239 5934

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Speaker: Zhesen Yang (IOP, CAS)

Abstract:

Topological nodal line semimetals can host stable chained, linked, or knotted line degeneracies in momentum space protected by symmetries. In this talk, I will show how to use the Jones polynomial (which is a knot invariant) to classify these semimetals. I will also show that every possible change in Jones polynomial is attributed to the local evolutions around every point where two nodal lines touch. As an application of our theory, I will illustrate that nodal chain semimetals with four touching points can evolve to a Hopf link. Finally, I will extend our theory to 3D non-Hermitian exceptional line semimetals.

Reference: Phys. Rev. Lett. 124, 186402 (2020)