Topology vs. interaction in fragile bands

Add to your list(s) Download to your calendar using vCal

• Ady Stern, Weizmann Institute of Science
• Thursday 29 April 2021, 14:00-15:00
• Details of video conferencing will be distributed nearer the time..

If you have a question about this talk, please contact Jan Behrends.

Topological systems of non-interacting electrons may be forced by their topological nature to have a gapless spectrum. As two examples, Integer quantum Hall states and topological insulators must carry gapless edge states, which allow them to carry current. Whether interaction between the electrons may turn a gapless conductor into a fully gapped insulator depends on the case at hand, with a negative answer for the first example and a positive for the second.

In this talk I will review these two examples, and then focus on bands of fragile topology. I will explain what fragile topology is as well as how and when it forbids a gapped spectrum at the non-interacting level. Then, I will show that interactions may be powerful enough to overcome the decree issued by topology, and explain how they do that. Finally, I will discuss relevance to twisted bi-layers of graphene.

This talk is part of the Theory of Condensed Matter series.

This talk is included in these lists:

• All Cavendish Laboratory Seminars
• All Talks (aka the CURE list)
• Centre for Health Leadership and Enterprise
• Combined TCM Seminars and TCM blackboard seminar listing
• Details of video conferencing will be distributed nearer the time.
• Featured lists
• Lennard-Jones Centre external
• ME Seminar
• Neurons, Fake News, DNA and your iPhone: The Mathematics of Information
• PMRFPS's
• School of Physical Sciences
• Theory of Condensed Matter
• Thin Film Magnetic Talks
• few29

Note that ex-directory lists are not shown.