Continuum model for the terahertz dielectric response of glasses
Phys. Rev. B 114, 074205 – Published 27 August, 2026
DOI: https://doi.org/10.1103/sjkh-zd6t
Abstract
Boson peak dynamics in glasses produce a robust crossover in the terahertz (THz) dielectric response that standard Debye or Lorentz models do not capture. We develop a continuum description of this THz response, coupling an infrared-effective charge fluctuation spectrum to a frequency-dependent shear modulus, and apply it to glycerol glass. The model reproduces the measured complex dielectric function and the nearly linear infrared light-vibration coupling around the boson peak, and it highlights the dominant role of transverse shear dynamics.
