Bound for entropy and viscosity ratio of strange quark matter

Abstract

High energy density (ǫ) and temperature (T) links general relativity and hydrodynamics leading to a lower bound for the ratio of shear viscosity (η) and entropy density (s). We get the interesting result that the bound is saturated in the simple model for quark matter that we use for strange stars at the surface for T ∼ 80 M eV . At this T we have the possibility of cosmic separation of phases. At the surface of the star where the pressure is zero -the density ǫ has a fixed value for all stars of various masses with correspondingly varying central energy density ǫ c . Inside the star where this density is higher, the ratio of η/s is larger and are like the known results found for perturbative QCD. This serves as a check of our calculation. The deconfined quarks at the surface of the strange star at T = 80 M eV seem to constitute the most perfect interacting fluid permitted by nature.

AdS/CFT aspects of the cosmological QCD phase transition

“…In addition, an interesting relation between the KSS bound and strange quark stars, is shown in [118]. The authors argued that, the surface of quark stars at the temperature T ∼ 80 MeV, has already saturated the KSS bound.…”

Chromothermal oscillations and collapse of strange stars to black holes: astrophysical implications

“…Throughout this work, we have assumed that the stars are isothermal even at higher temperatures. Random motions of quarks at very high velocities (0.5–0.7) as quoted in Bagchi et al (2007) will facilitate isothermal configurations. For theoretical interest, we discuss isentropic configurations in .…”