On the temperature dependence of the shear viscosity and holography

• Published in: The journal of high energy physics Vol. 2012; no. 8
• Main Authors: Cremonini, Sera, Gürsoy, Umut, Szepietowski, Phillip
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.08.2012; Springer Nature B.V
• Subjects: Classical and Quantum Gravitation; Couplings; Density ratio; Dilatons; Elementary Particles; High energy physics; Holography; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Relativity Theory; Scalars; Shear viscosity; String Theory; Temperature dependence; Viscosity; Gauge-gravity correspondence; AdS-CFT Correspondence; Phenomenological Models; Holography and quark-gluon plasmas
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP08(2012)167

A bstract We examine the structure of the shear viscosity to entropy density ratio in holographic theories of gravity coupled to a scalar field, in the presence of higher derivative corrections. Thanks to a non-trivial scalar field profile, in this setup generically runs as a function of temperature. In particular, its temperature behavior is dictated by the shape of the scalar potential and of the scalar couplings to the higher derivative terms. We consider a number of dilatonic setups, but focus mostly on phenomenological models that are QCD-like. We determine the geometric conditions needed to identify local and global minima for as a function of temperature, which translate to restrictions on the signs and ranges of the higher derivative couplings. Finally, such restrictions lead to an holographic argument for the existence of a global minimum for in these models, at or above the deconfinement transition.