Date : 2nd of June, 16:00 pm CET
Speaker : Rene Meyer (University of Wurzburg)
Title: Strongly Correlated Dirac Materials, Electron Hydrodynamics & AdS/CFT
Abstract: A current challenge in condensed matter physics is the realization of strongly correlated, viscous electron fluids. These fluids are not amenable to the perturbative methods of Fermi liquid theory, but can be described by holography, that is, by mapping them onto a weakly curved gravitational theory via gauge/gravity duality. The canonical system considered for realizations has been graphene, which possesses Dirac dispersions at low energies as well as significant Coulomb interactions between the electrons. In this talk, after introducing basic notions of hydrodynamics and holography, I will discuss Kagome systems which, with electron fillings adjusted to the Dirac nodes of their band structure, provide a much more compelling platform for realizations of viscous electron fluids, including non-linear effects such as turbulence. In particular, in stoichiometric Scandium (Sc) Herbertsmithite, the fine-structure constant, which measures the effective Coulomb interaction and hence reflects the strength of the correlations, is enhanced by a factor of about 3.2 as compared to graphene. I will present a holographic model which includes the leading finite coupling corrections and allows to estimate the ratio of shear viscosity over entropy density in Sc-Herbertsmithite, and find it about three times smaller than in graphene. These findings put, for the first time, the turbulent flow regime described by holography within the reach of experiments.