Exceptional Topology of Non-Hermitian Systems: from Theoretical Foundations to Novel Quantum Sensors

CET: 9:00a.m. - 10:15a.m. on March 3, 2021
JST: 5:00p.m. - 6:15p.m. on March 3, 2021
EST: 3:00a.m. - 4:15a.m. on March 3, 2021

In a broad variety of physical scenarios ranging from classical meta-materials to open quantum systems, non-Hermitian (NH) Hamiltonians have proven to be a powerful and conceptually simple tool for effectively describing dissipation. Motivated by recent experimental discoveries, investigating the topological properties of such NH systems has become a major focus of current research. In this talk, I give an introduction to this rapidly growing field, and present our latest results. Specifically, we discuss the occurrence of novel gapless topological phases unique to NH systems. There, the role of spectral degeneracies familiar from Hermitian systems such as Weyl semimetals is played by exceptional points at which the effective NH Hamiltonian becomes non-diagonalizable. Furthermore, we show how guiding principles of topological matter such as the bulk boundary correspondence are qualitatively changed in the NH realm. Finally, we demonstrate that the sensitivity of NH systems to small changes in the boundary conditions may be harnessed to devise novel high-precision sensors.

*Detailed information about the seminar refer to the email.