

Dipartimento di Fisica  A602  Zoom

Seminar
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Higherdimensional topological phases play a key role in understanding the lowerdimensional topological phases and the related topological responses through a dimensional reduction procedure. In this talk, I present a 4+1D Diractype Hamiltonian protected by CPsymmetry, whose 3D boundary supports an odd number of Dirac cones. This system supports (4+1)D quantum spin and valley Hall effects. A specific perturbation splits each bulk massive Dirac cone into two valleys separated in energymomentum space with opposite second Chern numbers, in which the 3D boundary modes become a nodal sphere or a Weyl semimetallic phase.
By introducing the electromagnetic (EM) and pseudoEM fields, exotic topological responses of our system are revealed, which are found to be described by the (4+1)D mixed ChernSimons theories in the lowenergy regime. Notably, several topological phase transitions occur when the bulk gap closes by giving rise to exotic doublenodalline/nodalhypertorus gapless phases. Finally, I show how to probe experimentally these topological effects in cold atoms.
Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infnit.zoom.us/j/8573185271
Meeting ID: 857 318 5271