$U(1)$ current from the AdS/CFT: diffusion, conductivity and causality
Abstract
For a holographically defined finite temperature theory, we derive an off-shell constitutive relation for a global current driven by a weak external non-dynamical electromagnetic field. The constitutive relation involves an all order gradient expansion resummed into three momenta-dependent transport coefficient functions: diffusion, electric conductivity, and "magnetic" conductivity. These transport functions are first computed analytically in the hydrodynamic limit, up to third order in the derivative expansion, and then numerically for generic values of momenta. We also compute a diffusion memory function, which, as a result of all order gradient resummation, is found to be causal.
Cite
@article{arxiv.1511.08789,
title = {$U(1)$ current from the AdS/CFT: diffusion, conductivity and causality},
author = {Yanyan Bu and Michael Lublinsky and Amir Sharon},
journal= {arXiv preprint arXiv:1511.08789},
year = {2016}
}
Comments
v1: 26 pages, 12 figures; v2: 29 pages, 9 multi-figures, revised section 6, added one summary(section 7) and one appendix, to be published in JHEP