# Out-of-equilibrium dynamical equations of infinite-dimensional particle systems. II. The anisotropic case under shear strain

## TL;DR

This paper extends the dynamical mean field theory of high-dimensional particle systems to include shear strain, deriving equations that describe the system's response and yielding behavior under shear in the infinite-dimensional limit.

## Contribution

It introduces a simplified dynamical framework for anisotropic particle systems under shear in high dimensions, enabling exact analysis of rheological properties and glass response.

## Key findings

- Derived one-dimensional stochastic process with strain-dependent kernels
- Provided exact equations for particle displacements and shear stress fluctuations
- Formulated state-following equations for glass response to shear

## Abstract

As an extension of the isotropic setting presented in the companion paper [J. Phys. A 52, 144002 (2019)], we consider the Langevin dynamics of a many-body system of pairwise interacting particles in $d$ dimensions, submitted to an external shear strain. We show that the anisotropy introduced by the shear strain can be simply addressed by moving into the co-shearing frame, leading to simple dynamical mean field equations in the limit ${d\to\infty}$. The dynamics is then controlled by a single one-dimensional effective stochastic process which depends on three distinct strain-dependent kernels - self-consistently determined by the process itself - encoding the effective restoring force, friction and noise terms due to the particle interactions. From there one can compute dynamical observables such as particle mean-square displacements and shear stress fluctuations, and eventually aim at providing an exact ${d \to \infty}$ benchmark for liquid and glass rheology. As an application of our results, we derive dynamically the 'state-following' equations that describe the static response of a glass to a finite shear strain until it yields.