Welcome to our group homepage!
Our group studies collective phenomena in quantum manybody systems that arise from the
intricate interplay of topology, strong correlations, and spinorbit coupling.
In our work we typically complement analytical
approaches by a variety of sophisticated numerical techniques that exploit concepts
from statistical physics, quantum information theory, and computer science.
We are embedded in a lively research environment at the
Institute for Theoretical Physics
in Cologne and part of a number of collaborative research and funding
initiatives together with our experimental colleagues in the
Physics Department.
Recent highlights
 Emergence of a fielddriven U(1) spin liquid in the Kitaev honeycomb model
Nature Comm. 10, 530 (2019)
 Monte Carlo Studies of Quantum Critical Metals
Annu. Rev. Condens. Matter Phys. 10, 63 (2019)
Commentaries by Andrey Chubukov and Jörg Schmalian on this line of research for the condensed matter journal club.  Topological Mechanics from Supersymmetry
arXiv:1809.08248
 Machine learning quantum phases of matter beyond the fermion sign problem
Scientific Reports 7, 8823 (2017)
More on unsupervised quantum phase recognition in arXiv:1707.00663
Fun stuff

These threedimensional tricoordinated lattice structures are underlying our recent studies of 3D Kitaev models,
which we have shown to host an unusually rich variety of Z_{2} spin liquids that are all analytically tractable. Examples
include gapless spin liquids with Majorana Fermi surfaces or topologically protected Weyl nodes,
as discussed in this complete classification.
You can get threedimensional prints of these models (depicted above) from shapeways (more cool models here) — unfortunately, shapeways recently altered their pricing structure resulting in an almost 10fold increase of printing costs for these objects.
If you want to further delve into these lattices, check out these VESTA files: (10,3)a, (10,3)b, (10,3)c, (9,3)a, (8,3)a, (8,3)b, (8,3)c, and (8,3)n.