Tensor network studies of SrCu₂(BO₃)₂ under pressure and in a magnetic field

The frustrated quantum antiferromagnet SrCu₂(BO₃)₂, which is effectively described by the Shastry-Sutherland model, exhibits a very rich phase diagram as a function of pressure and magnetic field, including an intriguing sequence of magnetization plateaus, several supersolid phases, a finite-temperature critical point, and more. However, its numerical study is very challenging because large parts of the phase diagram are inaccessible by Quantum Monte Carlo due to the negative sign problem. In this talk I will report on recent progress in the accurate study of this model using infinite projected entangled-pair states (iPEPS), a tensor network ansatz to represent states in the 2D thermodynamic limit, and show how it helped to shed new light on the fascinating properties of SrCu₂(BO₃)₂. Based on a recent extension of iPEPS to layered systems, we find that the inclusion of an interlayer coupling leads to a better agreement between experiments and theory regarding the extent of the intermediate plaquette phase.