QCD viscosity to entropy density ratio in the hadronic phase
Journal
Physical Review
Journal Volume
D76
Pages
114011
Date Issued
2007-03
Author(s)
Abstract
The shear viscosity η of QCD in the hadronic phase is computed by the coupled Boltzmann equations of pions and nucleons in low temperatures and low baryon-number densities. The η to entropy density ratio η/s maps out the nuclear gas-liquid phase transition by forming a valley tracing the phase transition line in the temperature-chemical potential plane. When the phase transition turns into a crossover, the η/s valley gradually disappears. We suspect the general feature for a first-order phase transition is that η/s has a discontinuity in the bottom of the η/s valley. The discontinuity coincides with the phase transition line and ends at the critical point. Beyond the critical point, a smooth η/s valley is seen. However, the valley could disappear further away from the critical point. The η/s measurements might provide an alternative to identify the critical points. © 2007 The American Physical Society.
Type
journal article