Speaker
Description
In this work we make an attempt to understand the dynamics of bulk viscosity near QCD phase transition. In particular we try to establish a relationship between singular behavior of bulk viscosity near critical region with some underlying symmetry of the system under consideration. We find that it is possible to relate singular behavior of bulk viscosity with the process of spontaneous chiral symmetry breaking of the system.
In this model We consider a strongly interacting fermionic matter, that is in a state with broken chiral symmetry and the system is placed slightly out of equilibrium. Invoking quasi-particle description for strongly interacting fermions, with dynamic quasi-particle excitations, we evaluate the thermodynamic properties of this matter in the relativistic mean-field (RMF) approximation.
Taking into consideration the Boltzmann transport equations in relaxation time approximation, we evaluate the transport properties of this medium. It is found that due to the coupling of fermionic quasi-particle excitations and σ modes (whose strength is governed by the expectation value of Chiral Condensate) ζ/s can get singular near transition region, both along O(4) transition line and in the Z(2) universality class.
Our results remain applicable in the limit of vanishing expectation value of Chiral Condensate that is in the limit T ∼ T_C, where σ-field strength is given by its vacuum expectation value.
It therefore seems appropriate to do away with the adhoc assumption of Hagedorn states, that were found to produce similar singular behavior of bulk viscosity near transition region in case of Hadron Resonance Gas models.
| Field of contribution | Theory |
|---|
