相关论文: Bound for entropy and viscosity ratio for strange …
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…
The shear viscosity to entropy density ratio ({\eta}/s) of quark gluon plasma produced in ultra- relativistic heavy-ion collisions has been studied from the energy loss of heavy quarks in QGP medium. We have also studied the bulk viscosity…
We calculate the ratio eta/s, the shear viscosity (eta) to entropy density (s), which characterizes how perfect a fluid is, in weakly coupled real scalar field theories with different types of phase transitions. The mean-field results of…
We calculate the shear viscosity $\eta$ of a quark plasma through the two-flavor Nambu-Jona-Lasinio (NJL) model in the chiral limit, at finite temperature $T$, and baryon number chemical potential $\mu_B$. We solve the Boltzmann equation by…
We have studied strange star properties both at zero temperature and at finite temperatures and searched signatures of strange stars in gamma-ray, x-ray and radio astronomy. We have a set of Equations of State (EoS) for strange quark matter…
We investigate the temperature dependence of the shear viscosity to entropy density ratio $\eta/s$ using a piecewise linear parametrization. To determine the optimal values of the parameters and the associated uncertainties, we perform a…
The viscosity of hadronic matter is studied using a classical evaluation of the scattering angle and a quantum mechanical discussion based on phase shifts from a potential. Semi classical limits of the quantum theory are presented. A hard…
We determine finite temperature corrections to the heavy-quark (static) potential as a function of the shear viscosity to entropy density ratio in a strongly coupled, large-$N_c$ conformal field theory dual to five-dimensional Gauss-Bonnet…
Many counterexamples to the proposed KSS bound $\frac\eta s \ge \frac 1 {4\pi}$ depend on constructing systems with large numbers of species. As a result, the entropy density grows large and $\frac \eta s$ can be made arbitrarily small.…
The properties of strange quark matter and the structures of (proto-)strange stars are studied within the framework of an equivparticle model, where a new quark mass scaling and self-consistent thermodynamic treatment are adopted. Our…
Strange quark matter with the density of ~ 5\times 10^{14} g cm^{-3} might exist up to the surface of a strange star. This differs qualitatively from the case of a neutron star and opens observational possibilities to distinguish strange…
Nuclear multifragmentation in intermediate energy heavy ion collisions has long been associated with liquid-gas phase transition. We calculate the shear viscosity to entropy density ratio eta/s for an equilibrated system of nucleons and…
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…
The previous thermodynamic treatment for models with density and/or temperature dependent quark masses is shown to be inconsistent with the requirement of fundamental thermodynamics. We therefore study a fully self-consistent one according…
Shear viscosity measures the amount of internal friction in a simple fluid. In kinetic theory shear viscosity is related to momentum transport by quasi-particles, and the uncertainty relation implies that the ratio of shear viscosity eta to…
Because of the mass density-dependence, an extra term should be added to the expression of pressure. However, it should not appear in that of energy according to both the general ensemble theory and basic thermodynamic principle. We give a…
We reexamine the surface composition of strange stars. Strange quark stars are hypothetical compact stars which could exist if strange quark matter was absolutely stable. It is widely accepted that they are characterized by an enormous…
We calculate the shear viscosity $\eta$ in the quark-gluon plasma (QGP) phase within a virial expansion approach with particular interest in the ratio of $\eta$ to the entropy density $s$, i.e. $\eta/s$. The virial expansion approach allows…
The transport coefficients of strongly interacting matter are currently subject of intense theoretical and phenomenological studies due to their relevance for the characterization of the quark-gluon plasma produced in ultra relativistic…
The gap caused by a strong electric field between the quark surface and nuclear crust of a strange star is studied in an improved model including gravity and pressure as well as electrostatic forces. The transition from gap to crust is…