2011/08/12 by J. S. Langer, Langer, J. S.
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Liquid Crystal Research Advancements #Material Dynamics and Properties #Statistical Mechanics (cond-mat.stat-mech) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.1108.2738
openalex publication_date 2011/08/12 · openalex created_date 2019/07/30 · openalex updated_date 2026/07/28
The success of the shear-transformation-zone (STZ) theory in accounting for\nbroadly peaked, frequency-dependent, glassy viscoelastic response functions is\nbased on the theory's first-principles prediction of a wide range of internal\nSTZ transition rates. Here, I propose that the STZ's are the dynamic\nheterogeneities frequently invoked to explain Stokes-Einstein violations and\nstretched-exponential relaxation in glass-forming materials. I find that, to be\nconsistent with observations of Fickian diffusion near Tg, an STZ-based\ndiffusion theory must include cascades of correlated events, but that the\ntemperature dependence of the Stokes-Einstein ratio is determined by an\nSTZ-induced enhancement of the viscosity. Stretched-exponential relaxation of\ndensity fluctuations emerges from the same distribution of STZ transition rates\nthat predicts the viscoelastic behavior.\n