2014/04/30 by Nicholas P. Bailey, Thomas B. Schrøder, Jeppe C. Dyre · 11 citations
Chemical Engineering · Materials Science · Mathematics · Physics and Astronomy · #Binary number #Constant (computer programming) #Invariant (physics) #Isothermal process #Material Dynamics and Properties #Mathematics #Molecular dynamics #Physics #Quantum mechanics #Relaxation (psychology) #Scale invariance #Spectroscopy and Quantum Chemical Studies #Statistical physics #Thermodynamic properties of mixtures #Thermodynamics #cond-mat.stat-mech
paper · pdf · doi:10.1103/physreve.90.042310
published in Physical Review E 90(4), 042310 (American Physical Society) · Expanded to include simulation data, and accepted for publication in Phys. Rev. E
arxiv created 2014/10/13 · openalex publication_date 2014/10/20 · arxiv updated 2014/10/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Koperwas et al. showed in a recent paper [Phys. Rev. Lett. 111, 125701 (2013)] that the dynamic susceptibility χ4 as estimated by dielectric measurements for certain glass-forming liquids decreases substantially with increasing pressure along a curve of constant relaxation time. This observation is at odds with other measures of dynamics being invariant and seems to pose a problem for theories of glass formation. We show that this variation is in fact consistent with predictions for liquids with hidden scale invariance: Measures of dynamics at constant volume are invariant along isochrones, called isomorphs in such liquids, but contributions to fluctuations from long-wavelength fluctuations can vary. This is related to the known noninvariance of the isothermal bulk modulus. Considering the version of χ4 defined for the NVT ensemble, data from simulations of a binary Lennard-Jones liquid show in fact a slight increase with increasing density. This is a true departure from the formal invariance expected for this quantity.