Sudipa Upadhaya

Shear viscosity and phase diagram from Polyakov–Nambu–Jona-Lasinio model

We present a detailed study of the variation of shear viscosity η , with temperature and baryon chemical potential within the framework of the Polyakov–Nambu–Jona-Lasinio model. η is found to depend strongly on the spectral width of the quasiparticles present in the model. The variation of η across the phase diagram has distinctive features for different kinds of transitions. These variations have been used to study the possible location of the critical end point and are cross-checked with similar studies of variations of specific heat. Finally, using a parametrization of the freeze-out surface in heavy-ion collision experiments, the variation of the shear viscosity to entropy density ratio has also been discussed as a function of the center-of-mass energy of collisions.

Reparametrizing the Polyakov–Nambu–Jona-Lasinio model

The Polyakov

A comparative study on two different approaches of bulk viscosity in the Polyakov–Nambu–Jona-Lasinio model

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Polyakov–Nambu–Jona-Lasinio model in finite volumes

Nambu

Net Charge Fluctuations as a signal of QGP from Polyakov-Nambu-Jona-Lasinio model

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Transport coefficients in finite volume Polyakov--Nambu--Jona-Lasinio model

Jona-Lasinio model has been quite successful in describing various qualitative features of observables for strongly interacting matter, that are measurable in heavy-ion collision experiments. The question still remains on the quantitative uncertainties in the model results. Such an estimation is possible only by contrasting these results with those obtained from first principles using the lattice QCD framework. Recently a variety of lattice QCD data were reported in the realistic continuum limit. Here we make a first attempt at reparametrizing the model so as to reproduce these lattice data. We find excellent quantitative agreement for the equation of state. Certain discrepancies in the charge and strangeness susceptibilities as well as baryon-charge correlation still remain. We discuss their causes and outline possible directions to remove them.

Thermodynamics of strongly interacting matter in a hybrid model

We have gone through a comparative study on two different kinds of bulk viscosity expressions by using a common dynamical model. The Polyakov–Nambu–Jona-Lasinio (PNJL) model in the realm of mean-field approximation, including up to eight quark interactions for 2+1 flavor quark matter, is treated for this common dynamics. We have probed the numerical equivalence as well as discrepancy of two different expressions for bulk viscosity at vanishing quark chemical potential. Our estimation of bulk viscosity to entropy density ratio follows a decreasing trend with temperature, which is observed in most of the earlier investigations. We have also extended our estimation for finite values of quark chemical potential.

Bulk viscosity : a study from Polyakov-Nambu-Jona-Lasinio model

We discuss the flavor Polyakov loop enhanced Nambu–Jona-Lasinio model in a finite volume. The main objective is to check the volume scaling of thermodynamic observables for various temperatures and chemical potentials. We observe the possible violation of the scaling with system size in a considerable window along the whole transition region in the plane.