We discuss a cosmology in which cold dark-matter particles decay into relativistic particles. We argue that such decays could lead naturally to a bulk viscosity in the cosmic fluid. For decay lifetimes comparable to the present hubble age, this bulk viscosity enters the cosmic energy equation as an effective negative pressure. We investigate whether this negative pressure is of sufficient magni...

We derive the relativistic equations for stellar perturbations, including in a consistent way shear viscosity in the stress-energy tensor, and we numerically integrate our equations in the case of large viscosity. We consider the slow rotation approximation, and we neglect the coupling between polar and axial perturbations. In our approach, the frequency and damping time of the emitted gravitat...

We investigate the effect of antikaon condensed matter on bulk viscosity in rotating neutron stars. We use relativistic field theoretical models to construct the equation of state of neutron stars with the condensate, where the phase transition from nucleonic to K condensed phase is assumed to be of first order. We calculate the coefficient of bulk viscosity due to the non-leptonic weak interac...

Substantial collective flow is observed in collisions between large nuclei at BNL RHIC (Relativistic Heavy Ion Collider) as evidenced by single-particle transverse momentum distributions and by azimuthal correlations among the produced particles. The data are well reproduced by perfect fluid dynamics. A calculation of the dimensionless ratio of shear viscosity eta to entropy density s by Kovtun...

Rainer J. Fries,1,2,3 Berndt Müller,3,4 and Andreas Schäfer3,5 1Cyclotron Institute and Department of Physics, Texas A&M University, College Station, Texas 77843, USA 2RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA 3Yukawa Institute of Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan 4Department of Physics, Duke University, Durham, North Caroli...

In this paper we obtain the conservation equations of momentum-energy a relativistic fluid in flat space-time. Three mechanisms for energy and momentum transferring are considered, which are: perfect fluid, stress viscosity heat transfer mechanisms. The effect magnetic field is ignored paper. Also, connection non-relativistic seen paper, so, can be modified with influences.The method deriving a...

We compute the first bulk viscosity of cold CFL quark matter in the temperature regime where the contribution of mesons, quarks and gluons to transport phenomena is Boltzmann suppressed. In that regime dissipation occurs due to collisions of superfluid phonons, the Goldstone modes associated to the spontaneous breaking of baryon symmetry. We first review the hydrodynamics of relativistic superf...