منابع مشابه
Viscosity to entropy density ratio: violation of the lower bound at small temperatures
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.
متن کاملShear viscosity to entropy density ratio of a relativistic Hagedorn resonance gas
Article history: Received 16 October 2009 Received in revised form 22 December 2009 Accepted 8 January 2010 Available online 16 January 2010 Editor: W. Haxton The new state of matter produced at Relativistic Heavy Ion Collider reveals a strongly coupled quark– gluon plasma with an extremely small shear viscosity to entropy density ratio η/s. We calculate the η/s of an equilibrated hadron matter...
متن کاملThe ratio of viscosity to entropy density in a pion gas satisfies the KSS holographic bound
We evaluate the ratio of shear viscosity to entropy density in a pion gas employing the UehlingUehlenbeck equation and experimental phase-shifts parameterized by means of the SU(2) Inverse Amplitude Method. We find that the ratio for this monocomponent gas stays well above the KSS 1/(4π) bound. We find similar results with other sets of phase shifts and conclude the bound is nowhere violated. P...
متن کاملThe ratio of shear viscosity to entropy density in generalized theories of gravity
Near the horizon of a black brane solution in Anti-de Sitter space, the long-wavelength fluctuations of the metric exhibit hydrodynamic behaviour. For Einstein’s theory, the ratio of the shear viscosity of near-horizon metric fluctuations η to the entropy per unit of transverse volume s is η/s = 1/4π. We propose that, in generalized theories of gravity, this ratio is given by the ratio of two e...
متن کاملProposed lower bound for the shear viscosity to entropy density ratio in some dense liquids
Starting from relativistic quantum field theories, Kovtun et al. (2005) have quite recently proposed a lower bound η/s ≥ ~/(4πkB), where η is the shear viscosity and s the volume density of entropy for dense liquids. If their proposal can eventually be proved, then this would provide key theoretical underpinning to earlier semiempirical proposals on the relation between a transport coefficient ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of High Energy Physics
سال: 2010
ISSN: 1029-8479
DOI: 10.1007/jhep01(2010)068