A method for measuring the dispersion of elastic waves in disordered computer-solids
arXiv:2607.11395
The paper introduces the imposed wave method (IWM), a computational technique that directly measures the dispersion of elastic waves in disordered solid models without fitting, and validates it against Hessian diagonalization while exploring finite‑size effects and a disorder metric linked to wave attenuation.
Abstract
The dispersion of elastic waves in disordered solids plays a key role in determining the vibrational density of states and harmonic wave attenuation rates. As such, the availability of robust computational approaches to the precise extraction of the dispersion is of key importance. Here we present a simple method -- the imposed wave method (IWM) -- , which provides direct access to the dispersion of elastic waves in computer models of solids, without any fitting involved. We directly benchmark the method against the `ground-truth' obtained from direct diagonalization of solids' hessian matrices, to find good agreement. We discuss limitations of and finite-size effects in the method, and show that exploiting the method's finite-size scaling provides access to a fundamental quantifier of mechanical disorder that determines wave attenuation rates and spectral widths.
6 pages, 6 figures