Probing Many-body Effects on the Potential Energy Landscape of Glass through Finite-Difference Hessian Analysis

The potential energy landscape (PEL) provides a framework for understanding the structural disorder and stability of glassy systems. We perform a comparative Hessian-matrix analysis of Kob–Andersen (KA) Lennard-Jones and metallic-glass (MG) models to explore how the nature of interatomic interactions influences the ruggedness of the PEL. By evaluating Hessians from atomic displacements at varying finite-difference steps, we analyze the evolution of the vibrational density of states (vDOS), participation ratio, and eigenvector field. While both systems exhibit quasilocalized low-frequency modes, under the same protocol, while reducing perturbation magnitude in Hessian measurement, both vDOS and eigenvector field of KA model exhibits a converging trend; however, in MG model, an additional diverging trend of is observed around 10^-5~10^-3 times nearest neighbor distance in both vDOS and eigenvector field. We attribute this behavior to the many-body term in the metallic interaction potential which increases the ruggedness of the PEL. These results demonstrate that Hessian-based analyses provide a sensitive probe of many-body effects underlying glass stability and landscape ruggedness.