The Physics & Astronomy Colloquium Series presents Cristian Batista of University of Tennessee and Oak Ridge National Lab. on “Magnetic Topological Solitons and Real Space Berry Curvature” on Friday, Nov. 6, at 4:10 p.m. at an Online Departmental Colloquium.

Abstract: Inspired by the work Herman Hemholtz, William Thompson proposed in 1867 that atoms could be vortices in aether. While later experiments put this proposal out of business, thinking of topological solitons as emerging building blocks or artificial atoms is very appealing. Indeed, more recent developments, that started around the 1960's, have demonstrated that nature has plenty of room for finding updated versions of aether. The aether of quantum magnets is the vector field of magnetic moments, whose topological solitons can be regarded as emergent mesoscale atoms. Like real atoms, these solitons form periodic arrays or crystals whose organizing principles are dictated by symmetry, anisotropy and competing microscopic interactions. Moreover, these magnetic textures generate an effective compact U(1) gauge field, minimally coupled to the conduction electrons, that can reach astronomical values.

We will see that the emergent magnetic field is related to a geometric property known as real space Berry curvature , whose general (covariant) form must be modified in the presence of relativistic spin-orbit coupling.