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Quantum critical scaling and holographic bound for transport coefficients near Lifshitz points

Inkof, Gian Andrea; Küppers, Joachim M. C.; Link, Julia M.; Goutéraux, Blaise; Schmalian, Jörg

The transport behavior of strongly anisotropic systems is significantly richer compared to isotropic ones. The most dramatic spatial anisotropy at a critical point occurs at a Lifshitz transition, found in systems with merging Dirac or Weyl point or near the superconductor-insulator quantum phase transition. Previous work found that in these systems a famous conjecture on the existence of a lower bound for the ratio of a shear viscosity to entropy is violated, and proposed a generalization of this bound for anisotropic systems near charge neutrality involving the electric conductivities. The present study uses scaling arguments and the gauge-gravity duality to confirm the previous analysis of universal bounds in anisotropic Dirac systems. We investigate the strongly-coupled phase of quantum Lifshitz systems in a gravitational Einstein-Maxwell-dilaton model with a linear massless scalar which breaks translations in the boundary dual field theory and sources the anisotropy. The holographic computation demonstrates that some elements of the viscosity tensor can be related to the ratio of the electric conductivities through a simple geometric ratio of elements of the bulk metric evaluated at the horizon, and thus obey a generalized bound, while others violate it. ... mehr

Zugehörige Institution(en) am KIT Institut für Theoretische Festkörperphysik (TFP)
Institut für Theorie der Kondensierten Materie (TKM)
Publikationstyp Forschungsbericht/Preprint
Publikationsmonat/-jahr 11.2020
Sprache Englisch
Identifikator KITopen-ID: 1000126965
Umfang 16 S.
Vorab online veröffentlicht am 17.11.2020
Nachgewiesen in arXiv
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