Browsing by Author "Sun, Jia-Rui"

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Mimic the optical conductivity in disordered solids via gauge/gravity duality
(2014-02-05)
Sun, Jia-Rui
;
Wu, Shang-Yu
;
Zhang, Hai-Qing
;
物理研究所
;
Institute of Physics
We study the optical conductivity in a (2 + 1)-dimensional non-relativistic field theory holographically dual to a (3 + 1)-dimensional charged Lifshitz black brane within the Einstein-Maxwell-dilaton theory. Surprisingly, we find that the optical AC conductivity satisfies the nontrivial (non-)power law scaling in the high frequency regime rather than approaching to a constant when the dynamical critical exponent z > 1, which is qualitatively similar to those in various disordered solids in condensed matter systems. Besides, this (non-)power law scaling behavior shows some universality, which is robust against the temperatures. We argue that the peculiar scaling behavior of AC conductivity may stem from the couplings of the dilaton field with the gauge fields and also the logarithmic behavior near the boundary in the Lifshitz spacetime. (C) 2014 The Authors. Published by Elsevier B.V. All rights reserved.
Novel features of the transport coefficients in Lifshitz black branes
(2013-04-23)
Sun, Jia-Rui
;
Wu, Shang-Yu
;
Zhang, Hai-Qing
;
物理研究所
;
Institute of Physics
We study the transport coefficients, including the conductivities and shear viscosity of the non-relativistic field theory dual to the Lifshitz black brane with multiple U(1) gauge fields by virtue of the gauge/gravity duality. Focusing on the case of double U(1) gauge fields, we systematically investigate the electric, thermal, and thermoelectric conductivities for the dual nonrelativistic field theory. In the large frequency regime, we find a nontrivial power law behavior in the electric alternating current conductivity when the dynamical critical exponent z > 1 in (2 + 1)-dimensional field theory. The relations between this novel feature and the "symmetric hopping model" in condensed matter physics are discussed. In addition, we also show that the Kovtun-Starinets-Son bound for the shear viscosity to the entropy density is not violated by the additional U(1) gauge fields and dilaton in the Lifshitz black brane. DOI: 10.1103/PhysRevD.87.086005