Fractional spin through quatum (super)Virasoro algebras

The splitting of a $Q$-deformed boson, in the Q\to q=e^{\frac{\QTR{rm}{2\pi i}}{\QTR{rm}{k}}} limit, is discussed. The equivalence between a $Q$-fermion and an ordinary one is established. The properties of the quantum (super)Virasoro algebras when their deformation parameter $Q$ goes to a root of unity, are investigated. These properties are shown to be related to fractional supersymmetry and $k$-fermionic spin

Dissociation of Quarkonium in hot and Dense Media in an Anisotropic Plasma in the Non-Relativistic Quark Model

In this paper, quarkonium dissociation is investigated in an anisotropic plasma in the hot and dense media. For that purpose, the multidimensional Schrodinger equation is solved analytically by Nikiforov-Uvarov (NU) method for the real part of the potential in an anisotropic medium. The binding energy and dissociation temperature are calculated. In comparison with an isotropic medium, the binding energy of quarkonium is enhanced in the presence of an anisotropic medium. The present results show that the dissociation temperature increases with increasing anisotropic parameter for 1S state of the charmonium and bottomonium. We observe that the lower baryonic chemical potential has small effect in both isotropic and anisotropic media. A comparison is presented with other pervious theoretical works.Comment: 11 pages, 10 figures, 1 table

Dissipative Processes in the Early Universe: Bulk Viscosity

In this talk, we discuss one of the dissipative processes which likely take place in the Early Universe. We assume that the matter filling the isotropic and homogeneous background is to be described by a relativistic viscous fluid characterized by an ultra-relativistic equation of state and finite bulk viscosity deduced from recent lattice QCD calculations and heavy-ion collisions experiments. We concentrate our treatment to bulk viscosity as one of the essential dissipative processes in the rapidly expanding Early Universe and deduce the dependence of the scale factor and Hubble parameter on the comoving time $t$. We find that both scale factor and Hubble parameter are finite at $t=0$, revering to absence of singularity. We also find that their evolution apparently differs from the one resulting in when assuming that the background matter is an ideal and non-viscous fluid.Comment: 8 pages, 2 eps figure, Invited talk given at the 7th international conference on "Modern Problems of Nuclear Physics", 22-25 September 2009, Tashkent-Uzbekista