Violation of universal lower bound for the shear viscosity to entropy density ratio in dark energy dominated accretion
Year: 2019
Type: article
Abstract: The universal lower bound of the ratio of shear viscosity to entropy density is suggested by the string theory and gauge duality for any matter. We examined the ratio of shear viscosity to entropy density for viscous accretion flow towards a central gravitating object in the presence of dark energy. The ratio appears close to the universal lower bound for certain optically thin, hot accretion flows as they are embedded by strong magnetic field. Dark energy is a kind of exotic matter which has negative pressure. So dark energy creates repulsive force between the accreting particles, which indicates that shear viscosity of the flow becomes very low. Dark energy as accreting fluid has very high entropy density. The ratio should reach near to the lowest value for dark energy accretion. We wish to study what happens to the shear viscosity to entropy density ratio for viscous dark energy accretion flow.
Source: The European Physical Journal C
Authors: Sandip Dutta, Ritabrata Biswas
Institution: University of Burdwan
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W2955670547