Related papers: Viscous Hydrodynamics and the Quark Gluon Plasma
Within a covariant parton cascade, we discuss the impact of both finite shear viscosity $\eta$ and freeze-out dynamics on the elliptic flow generated at RHIC. We find that the enhancement of $\eta/s$ in the cross-over region of the QGP…
We present transport coefficients (shear viscosity, $\eta$, and bulk viscosity, $\zeta$) for the gluon system obtained by the lattice QCD. This is an indispensable calculation towards the understanding of ``New State of Matter'' observed in…
We investigate the effects of a temperature-dependent shear viscosity over entropy density ratio eta/s on the flow anisotropy coefficients v_2 and v_4 in ultrarelativistic heavy-ion collisions at RHIC and LHC. We find that v_4 is more…
The lecture is a brief review of the following topics: (i) collective flow phenomena in heavy ion collisions. The data from RHIC indicate robust collective flows, well described by hydrodynamics with expected Equation of State. The…
The viscosity of the Quark-Gluon Plasma (QGP) is usually described holographically by the entropy-normalized dynamic viscosity $\eta/s$. However, other measures of viscosity, such as the kinematic viscosity $\nu$ and the Reynolds number…
We show that, in a holographic or gauge-gravity approach to the study of the Quark-Gluon Plasma, the specific entropy density of the plasma produced in a peripheral heavy-ion collision can be strongly suppressed relative to its value for…
Recently, it has been found that the kinematic viscosity of liquids at the minimum, $\nu_m$, can be expressed in terms of fundamental physical constants, giving $\nu_m$ on the order of $10^{-7}~{\rm m^2/s}$. Here, we show that the kinematic…
Experiments at the Relativistic Heavy Ion Collider (RHIC) suggest that the state of matter produced in the experiments has a low shear-viscosity to entropy-density ratio. We ask here the question what is this ratio in usual finite nuclei at…
In this contribution we present an alternative scenario for the large elliptic flow observed in relativistic heavy ion collisions. Motivated by recent results from Lattice QCD on flavor off-diagonal susceptibilities we argue that the matter…
Despite the viscosity of a fluid ranges over several orders of magnitudes and is extremely sensitive to microscopic structure and molecular interactions, it has been conjectured that its (opportunely normalized) minimum displays a universal…
We investigate the shear viscosity of leptons in a strongly coupled quark gluon plasma (QGP). We find that the shear viscosity due to the lepton-quark scattering is inversely proportional to the ratio of electric conductivity of the QGP to…
Viscous relativistic hydrodynamics in 3+1 dimensions is applied to describe heavy ion collisions at RHIC and LHC. We present calculations of observables that are sensitive to the longitudinal structure of the created system. In particular…
Employing a perturbative QCD based parton cascade we calculate the elliptic flow $v_2$ and its transverse momentum dependence $v_2(p_T)$ for the gluon matter created in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV. To make comparisons with…
The shear viscosity $\eta$ has been calculated by using the Green-Kubo relation in the framework of a partonic transport approach solved at cascade level. We compare the numerical results for $\eta$ obtained from the Green-Kubo correlator…
Experimental results obtained at the Relativistic Heavy Ion Collider (RHIC) have been interpreted in terms of a strongly interacting quark gluon plasma. The strongly interacting plasma is characterized by ``perfect fluidity'', i.e. a ratio…
The shear viscosity of the quark-gluon plasma is predicted to be lower than the collisional viscosity for weak coupling. The estimated ratio of the shear viscosity to entropy density is rather close to the ratio calculated by N = 4 super…
The quark gluon plasma produced in ultra-relativistic heavy-ion collisions exhibits remarkable features. It behaves like a nearly perfect liquid with a small shear viscosity to entropy density ratio and leads to the quenching of highly…
We report here recent analytical and numerical work on the theoretical treatment of the early stages of heavy ion collisions, that amounts to solving the classical Yang-Mills equations with fluctuating initial conditions. Our numerical…
Using chiral perturbation theory we investigate the QCD shear viscosity to entropy density ratio below the deconfinement temperature (~170 MeV) with zero baryon number density. It is found that the viscosity to entropy density ratio of QCD…
The matter created in relativistic heavy ion collisions is fairly well described by ideal hydrodynamics, and somewhat better described by viscous hydrodynamics. To this point, most viscous calculations have been two-dimensional, based on an…