Drexel University - Comprehensive, integrated academics enhanced by co-operative education, technology, and research opportunities. | Drexel University
Drexel University
Search events. View events.

All Categories

Click for help in using calendar displays. Print the contents of the current screen.
Display Format: 
Event Details
Notify me if this event changes.Add this event to my personal calendar.
Go Back
Physics Colloquium: Exceptional Topological Insulators
Start Date: 10/29/2020Start Time: 3:30 PM
End Date: 10/29/2020End Time: 4:30 PM

Event Description

Titus Neupert, PhD, University of Zurich


Since their discovery, three-dimensional topological insulators have become the focal point for research on topological quantum matter. Their key feature are conducting surface states resembling a single species of gapless Dirac electrons. Transcending the realm of quantum matter, the topological insulator phase has since been realized in many different settings including metamaterials, such as photonic and phononic crystals.

Most of such metamaterial platforms are accidentally or tunably lossy, such that their effective Hamiltonian description involves non-Hermitian terms due to the lack of energy conservation. The same holds for interacting electronic quantum systems in which quasiparticles attain a finite lifetime, for instance. Starting from the initial classification of topological matter based on Hermitian Hamiltonians, the study of systems with non-negligible loss and gain calls for an extension to non-Hermitian topological matter.

In this colloquium, I will introduce the exceptional topological insulator (ETI), a three-dimensional non-Hermitian topological state of matter that features exotic non-Hermitian surface states which can only exist within the three-dimensional topological bulk embedding. I will show how this phase can evolve from a Weyl semimetal or Hermitian three-dimensional topological insulator close to criticality when quasiparticles acquire a finite lifetime. The ETI does not require any symmetry to be stabilized. It is characterized by a bulk energy point gap, and exhibits robust surface states that cover the bulk gap as a single sheet of complex eigenvalues or with a single surface exceptional point. The ETI can be induced in genuine solid-state and metamaterial systems, thereby setting a paradigm for non-Hermitian topological matter.


Contact Information:
Name: Professor Jorn Venderbos
Email: jwv34@drexel.edu
Disque Hall, Room 919, 32 South 32nd Street, Philadelphia, PA 19104
  • Undergraduate Students
  • Graduate Students
  • Faculty

  • Display Month:

    Advanced Search (New Search)
    Date Range:
    Time Range:

    Special Features: 

    Select item(s) to Search

    Select item(s) to Search
    Select item(s) to Search
    Select item(s) to Search