Dissipative properties and isothermal compressibility of hot and dense hadron gas using non-extensive statistics

Tiwari, Swatantra Kumar (Aff1, 0000 0004 1769 7721, Discipline of Physics, School of Basic Sciences, Indian Institute of Technology Indore, Simrol, 453552, Indore, India) ; Tripathy, Sushanta (Aff1, 0000 0004 1769 7721, Discipline of Physics, School of Basic Sciences, Indian Institute of Technology Indore, Simrol, 453552, Indore, India) ; Sahoo, Raghunath (Aff1, 0000 0004 1769 7721, Discipline of Physics, School of Basic Sciences, Indian Institute of Technology Indore, Simrol, 453552, Indore, India) ; Kakati, Nilotpal (Aff2, 0000 0004 0406 1521, Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, 140306, Mohali, India)

15 November 2018

Abstract: We evaluate the transport properties such as shear viscosity ( η ), bulk viscosity ( ζ ) and their ratios over entropy density ( s ) for hadronic matter using relativistic non-extensive Boltzmann transport equation (NBTE) in relaxation time approximation (RTA). In NBTE, we argue that the system far from equilibrium may not reach to an equilibrium described by extensive (Boltzmann-Gibbs (BG)) statistics but to a q -equilibrium defined by Tsallis non-extensive statistics after subsequent evolution, where q denotes the degree of non-extensivity. We observe that η/s and ζ/s decrease rapidly with temperature ( T ) for various q -values. As q increases, the magnitudes of η/s and ζ/s decrease with T . We also show the upper mass cutoff dependence of these ratios for a particular q and find that they decrease with the increase in mass cutoff of hadrons. Further, we present the first estimation of isothermal compressibility ( κT ) using non-extensive Tsallis statistics at finite baryon chemical potential ( μB ). It is observed that, κT changes significantly with the degree of non-extensivity. We also study the squared speed of sound ( cs2 ) as a function of temperature at finite baryon chemical potential for various q and upper mass cutoffs. It is noticed that there is a strong impact of q and mass cutoff on the behaviour of cs2 .


Published in: EPJC 78 (2018) 938
Published by: Springer/Società Italiana di Fisica
DOI: 10.1140/epjc/s10052-018-6411-y
License: CC-BY-3.0



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