Physics Seminar
Date: Monday, 11 November 2024
Time: 12:00 PM
Venue: Lecture Hall 1
Explorations in Topological Quantum Matter In and Out-of Equilibrium
Ranjani Seshadri
Boston College, USA.
11-11-24

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Abstract

I will start with an overview of a range of topological systems - mostly in two-dimensions - which host conducting modes at the boundary of an insulating bulk and have a non-trivial topological invariant. There are several interesting questions related to these novel phases - from “how graphene hosts robust edge states in the presence of spin-orbit interactions” to “how topology can manifest in Ising superconductors”. I will discuss the symmetries that protect the boundary modes in these systems.

The second part of my talk will deal with similar non-trivial boundary states generated by driving a solid-state system out of equilibrium using a time-dependent perturbation. When this perturbation is perfectly periodic, it can potentially generate “Floquet topological phases” in a system that was trivial to begin with. However, this perfect time periodicity is an idealization and in reality the drive has a switch on/off time. This is particularly relevant in the context of pump-probe experiments that employ ultrafast lasers as probes to study the physics of such topological phases.