Regensburg 2019 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 22: Critical Phenomena and Phase Transitions
DY 22.4: Vortrag
Dienstag, 2. April 2019, 14:45–15:00, H19
Quantum critical scaling and holographic bound for transport coefficients near Lifshitz points — •Gian Andrea Inkof1, Joachim Küppers1, Julia Link1, Blaise Goutéraux2, and Jörg Schmalian1,3 — 1Institute for Theory of Condensed Matter, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany — 2CPHT, École Polytechnique, 91128 Palaiseau Cedex, France — 3Institute for Solid State Physics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
The present study uses scaling arguments and holography to investigate universal bounds appearing in strongly coupled QFT. The analysis focuses on the critical regime of anisotropic graphene-like systems at charge neutrality. Through scaling techniques we state a generalization to the anisotropic case of both the shear-viscosity to entropy density ratio and the charge diffusivity bounds. In order to obtain scale dimensionless quantities, we take into account the electric transport for the former, while the structure of the latter is supposed to remain unchanged. We investigate the strongly coupled phase in a gravitational EMD model, where both translations and rotations are broken. The holographic computation suggests a relation between some entries of the η/s-tensor and the conductivities, similar to the one predicted with the scaling. From the IR critical geometry, we derive a recursion formula which allows us to analytically express the diffusion constants in terms of the square butterfly velocities. The proportionality factor turns out to be direction-independent, linear in the inverse temperature, and related to the anisotropic exponents of the dual field theory.