Viscosity to entropy density ratio: violation of the lower bound at small temperatures
نویسنده
چکیده
We show that in theories where the lowest energy excitations are not quasiparticles but they form a continuum, the shear viscosity to entropy density ratio goes to zero as the temperature goes to zero. In these theories therefore there is no lower bound for the shear viscosity to entropy density ratio, in contrast to the predictions coming from the AdS/CFT correspondence.
منابع مشابه
Viscosity bound and causality violation.
In recent work we showed that, for a class of conformal field theories (CFT) with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio, eta/s, could violate the conjectured Kovtun-Starinets-Son viscosity bound, eta/s > or = 1/4 pi. In this Letter we argue, in the context of the same model, that tuning eta/s below (16/25)(1/4 pi) induces microcausality violation in the CFT, re...
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