Topology of finite-lifetime quasipartices and non-Hermitian quantum mechanics
Quasiparticles in many-body systems generally have a finite lifetime due to electron-electron, electron-phonon and electron-impurity scatterings. I will show that in small-gap systems, the decay of a quasiparticle can alter its energy-momentum dispersion significantly, for example, transform a two-dimensional Dirac point into a nodal arc that ends at topological exceptional points. Properties of finite-lifetime quasiparticles are naturally described by non-Hermitian Hamiltonians that include imaginary part of self energy.
Host: Tom Iadecola
CMTC Conference Room (2205 Toll Physics Bldg.)