[Seminar] "Kitaev-Model in a [111] Magnetic Field and its Topological Excitations" Dr. Matthias Gohlke

Abstract:

Quantum spin-liquids represent novel phases of matter that host emergent fractionalized excitations. The Kitaev model is a two-dimensional model system in this context and relevant for recent experiments on putative quantum spin-liquid materials. We employ matrix product state based numerical methods to study the Kitaev model coupled to magnetic field along [111] direction. Using infinite DMRG, we confirm three phases with vastly different transition fields depending on the sign of the Kitaev

exchange: A topological phase hosting non-abelian anyons at low fields, an intermediate regime only existing for antiferromangetic Kitaev exchange, and a field-polarized phase hosting topological magnons. A novel time-evolution based on matrix product operators enables to study dynamical signatures of each phase.