Visible light exposure of galaxy cluster Abell 2744 from NASA/ESA Hubble Space Telescope and ESO's Very Large Telescope, X-ray data from NASA's Chandra X-ray Observatory & math reconstruction of dark matter location. D. Coe & J. Merten/ESO/NASA/ESA/CXC
Theory Seminar

Physics Theory Seminar with Kirill Shtengel on Antiferromagnets

Kirill Shtengel (Hosted by Nussinov) from University of California Riverside will be presenting the seminar "Order by Disorder in Classical Kagome Antiferromagnets with Chiral Interactions"

The Heisenberg antiferromagnet on the kagome lattice is an archetypal example of how large ground state degeneracies arise, and how they may get resolved by thermal and quantum fluctuations. Augmenting the Heisenberg model by chiral spin interactions has proved to be of particular interest in the discovery of chiral quantum spin liquids. I will focus on  the classical variant of this chiral kagome model, which exhibits, similar to the classical Heisenberg antiferromagnet, a remarkably large and structured ground-state manifold combining continuous and discrete degrees of freedom. This allows for a rich set of order-by-disorder phenomena. Degeneracy lifting by thermal and quantum fluctuations occurs in a highly selective way that, among other interesting effects, provides a semiclassical route to an emergent Z_2 spin liquid. 

Based on https://arxiv.org/abs/2110.11427

Zoom link available upon request at physics@wustl.edu.
Post-docs and students' Q&A with the speaker starts at 2:15 pm. Contact Garrett King for the Q&A Zoom link.