Nonequilibrium mode-coupling theory for uniformly sheared underdamped systems

TL;DR

This paper develops a mode-coupling theory for underdamped systems under shear with an isothermal condition, revealing unique relaxation behaviors and differences from overdamped systems, with negligible correlation effects on density-current modes.

Contribution

It introduces a nonequilibrium mode-coupling theory for sheared underdamped systems with isothermal conditions, highlighting distinct relaxation dynamics from overdamped models.

Findings

Shear stress relaxes significantly in the alpha regime due to cooling effects.

Underdamped MCT differs from overdamped MCT at long times despite early similarities.

Correlation effects on density-current modes are negligible in sheared thermostated systems.

Abstract

Mode-coupling theory for uniformly sheared underdamped systems with an isothermal condition is presented. As a result of the isothermal condition, it is shown that the shear stress exhibits significant relaxation at the alpha-relaxation regime due to the cooling effect which is accompanied by the growth of the current fluctuation. This indicates that nonequilibrium underdamped MCT is not equivalent to the corresponding overdamped MCT, even at long time-scales after the early stage of the beta relaxation. It is verified that the effect of correlations to the density-current modes is, however, negligible in sheared thermostated underdamped systems.