Three-dimensional topological insulators have become a research focal point on topological quantum matter. A recent work led by the group of Titus Neupert now proposes an analogue in dissipative systems, which are described by non-Hermitian operators, the exceptional topological insulator (ETI). Like normal topological insulators, the ETI hosts exotic surface states. Mathematically, they have a band structure with a so-called exceptional point, which can only exist because of the 3D topological bulk embedding. Such a phase could for instance describe the physics of quasiparticles in Weyl semimetals with strong electron-phonon interaction.
arXiv:2008:01090