Physics Seminar
Date: Tuesday, 17 October 2023
Time: 11:30 AM
Venue: Lecture Hall 801
Emergent topology and its signatures in dissipative dynamics of topological condensed matter
Suraj S Hegde
Dresden University of Technology, Germany.
17-10-23

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Abstract

Topological characterisation of quantum phases of matter has been well studied both theoretically and experimentally for low-energy states of closed condensed matter systems. Dissipation and decoherence are sometimes considered as a hindrance or as an external perturbation that affect the topological features. In this talk, I present how we need to rethink the notion of topology for open quantum systems. Taking a paradigmatic example of a topological phase, a Chern insulator under going a dissipative evolution under Gorini-Kossakowski-Sudarshan-Lindblad equation, I show how the notion of spectral winding/topology of the damping generator gives rise quantum channels localised only at an edge and undergoing extremal damping. These damping channels are robust against perturbations, symmetry-protected and could be of use in quantum technologies. Further, the dynamics show signatures of ‘non-Hermitian exceptional points’ which have no counterparts in Hermitian topological phases. I also discuss how these effects are already being probed in experiments on photonic lattices and also how dissipative boundaries of Hermitian topological phases can harbour such unique phenomena.