2017/05/31 by Moupriya Das, Jason R. Green
Engineering · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Classical mechanics #Intermolecular force #Lyapunov exponent #Molecule #Observable #Perturbation (astronomy) #Phase Equilibria and Thermodynamics #Physics #Quantum mechanics #Quantum, superfluid, helium dynamics #Statistical physics #cond-mat.stat-mech #nlin.CD #physics.chem-ph #van der Waals force
paper · pdf · doi:10.1103/physrevlett.119.115502
published as Phys. Rev. Lett. 119, 115502 (2017) · 5 pages, 4 figures
openalex publication_date 2017/09/14 · arxiv created 2017/09/29 · arxiv updated 2017/10/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Bulk properties of equilibrium liquids are a manifestation of intermolecular forces. Here, we show how these forces imprint on dynamical fluctuations in the Lyapunov exponents for simple fluids with and without attractive forces. While the bulk of the spectrum is strongly self-averaging, the first Lyapunov exponent self-averages only weakly and at a rate that depends on the length scale of the intermolecular forces; short-range repulsive forces quantitatively dominate longer-range attractive forces, which act as a weak perturbation that slows the convergence to the thermodynamic limit. Regardless of intermolecular forces, the fluctuations in the Kolmogorov-Sinai entropy rate diverge, as one expects for an extensive quantity, and the spontaneous fluctuations of these dynamical observables obey fluctuation-dissipation-like relationships. Together, these results are a representation of the van der Waals picture of fluids and another lens through which we can view the liquid state.