Onset of collective excitations in the transverse dynamics of simple fluids

Eleonora Guarini, Martin Neumann, Alessio De Francesco, Ferdinando Formisano, Alessandro Cunsolo, Wouter Montfrooij, Daniele Colognesi, and Ubaldo Bafile
Phys. Rev. E 107, 014139 – Published 30 January 2023

Abstract

A thorough analysis of the transverse current autocorrelation function obtained by molecular dynamics simulations of a dense Lennard-Jones fluid reveals that even such a simple system is characterized by a varied dynamical behavior with changing length scale. By using the exponential expansion theory, we provide a full account of the time correlation at wavevectors Q between the upper boundary of the hydrodynamic region and Qp/2, with Qp being the position of the main peak of the static structure factor. In the Q range studied, we identify and accurately locate the wavevector at which shear wave propagation starts to take place, and show clearly how this phenomenon may be represented by a damped harmonic oscillator changing, in a continuous way, from an overdamped to an underdamped condition. The decomposition into exponential modes allows one to convincingly establish not only the crossover related to the onset of transverse waves but, surprisingly, also the existence of a second pair of modes equivalent to another oscillator that undergoes, at higher Q values, a similarly smooth over to underdamped transition.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
1 More
  • Received 9 June 2022
  • Revised 29 October 2022
  • Accepted 10 January 2023

DOI:https://doi.org/10.1103/PhysRevE.107.014139

©2023 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Eleonora Guarini1,*, Martin Neumann2, Alessio De Francesco3, Ferdinando Formisano3, Alessandro Cunsolo4, Wouter Montfrooij5, Daniele Colognesi6, and Ubaldo Bafile6

  • 1Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
  • 2Fakultät für Physik der Universität Wien, Kolingasse 14-16, A-1090 Wien, Austria
  • 3CNR-IOM & INSIDE@ILL c/o Operative Group in Grenoble (OGG) F-38042 Grenoble, France and Institut Laue Langevin (ILL), F-38042 Grenoble, France
  • 4Department of Physics, University of Wisconsin at Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
  • 5Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
  • 6Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata “Nello Carrara”, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy

  • *Corresponding author: guarini@fi.infn.it

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 107, Iss. 1 — January 2023

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review E

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×