Similarity between the kinematic viscosity of quark-gluon plasma and liquids at the viscosity minimum

• Main Author: Kostya Trachenko, Vadim Brazhkin, Matteo Baggioli
• Format: Article
• Language: English
• Published: SciPost 2021-05-01
• Series: SciPost Physics
• Online Access: https://scipost.org/SciPostPhys.10.5.118

Recently, it has been found that the kinematic viscosity of liquids at the minimum, $\nu_m$, can be expressed in terms of fundamental physical constants, giving $\nu_m$ on the order of $10^{-7}~{\rm m^2/s}$. Here, we show that the kinematic viscosity of quark-gluon plasma (QGP) has a similar value and support this finding by experimental data and theoretical estimations. The similarity is striking, given that the dynamic viscosity and the density of QGP are about 16 orders of magnitude larger than in liquids and that the two systems have disparate interactions and fundamental theories. We discuss the implications of this result for understanding the QGP including the similarity of flow and particle dynamics at the viscosity minimum, the associated dynamical crossover and universality of shear diffusivity.