https://doi.org/10.1140/epjc/s10052-021-09596-6
Regular Article - Theoretical Physics
Critical exponents and transport properties near the QCD critical endpoint from the statistical bootstrap model
1
Department of Physics, Shivaji University, 416 004, Kolhapur, Maharashtra, India
2
School of Physical Sciences, National Institute of Science Education and Research Bhubaneswar HBNI, 752050, Jatni, Odisha, India
3
Theory Division, Physical Research Laboratory, 380 009, Navarangpura, Ahmedabad, India
4
Department of Physics, University of Turin, Turin, Italy
5
INFN, Turin, Via Pietro Giuria 1, 10125, Turin, Italy
Received:
17
February
2021
Accepted:
29
August
2021
Published online:
7
September
2021
We present an estimate of the behavior of the shear and bulk viscosity coefficients when the QCD critical point is approached from the hadronic side, describing hadronic matter within the statistical bootstrap model of strong interactions. The bootstrap model shows critical behavior near the quark-hadron transition temperature if the parameter characterizing the degeneracy of Hagedorn states is properly chosen. We calculate the critical exponents and amplitudes of relevant thermodynamic quantities near the QCD critical point and combine them with an Ansatz for the shear and bulk viscosity coefficients to derive the behavior of these coefficients near the critical point. The shear viscosity to entropy density ratio is found to decrease when the temperature is increased, and to approach the Kovtun–Son–Starinets bound 
faster near the critical point, while the bulk viscosity coefficient is found to rise very rapidly.
© The Author(s) 2021
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