Impact of fragment formation on shear viscosity in the nuclear liquid-gas phase transition region

TL;DR

This study uses the ImQMD model to investigate how fragment formation during the nuclear liquid-gas phase transition affects shear viscosity, revealing the influence of phase transition dynamics on transport properties.

Contribution

It introduces a method to directly measure shear viscosity during phase transition in nuclear matter using the ImQMD model, highlighting the impact of fragment formation.

Findings

Fragment formation increases shear viscosity during phase transition.

Mean field effects significantly influence viscosity measurements.

Clumping correlates with changes in local stress tensor.

Abstract

Within the improved quantum molecular dynamic (ImQMD) model we follow the evolution of nuclear matter for planar Couette flow in a periodic box. We focus on the region of liquid-gas phase transition and extract the shear viscosity coefficient from the local stress tensor, directly following viscosity definition. By switching on and off the mean field and thus inducing the phase transition, we are able to observe the impact of clumping in the phase-transition region onto the viscosity.