title: Exposing a dynamical signature of the freezing transition through the sound propagation gap.
abstract: The conventional view of freezing holds that nuclei of the crystal phase form in the metastable fluid through purely stochastic thermal density fluctuations. The possibility of a change in the character of the fluctuations as the freezing point is traversed is beyond the scope of this perspective. Here we show that this perspective may be incomplete by examination of the time autocorrelation function of the longitudinal current, computed by molecular dynamics for the hard-sphere fluid around its freezing point. In the spatial window where sound is overdamped, we identify a change in the long-time decay of the correlation function at the known freezing points of monodisperse and moderately polydisperse systems. The fact that these findings agree with previous experimental studies of colloidal systems in which particle are subject to diffusive dynamics, suggests that the dynamical signature we identify with the freezing transition is a consequence of packing effects alone.
authors.affiliation: School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK.
authors.forename: V A
authors.initials: VA
authors.lastname: Martinez
authors.affiliation: CNR-ISC and Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, I-00185 Roma, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Zaccarelli
authors.affiliation: Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avenida Complutense, 28040 Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Sanz
authors.affiliation: Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avenida Complutense, 28040 Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Valeriani
authors.affiliation: Department of Applied Physics, Royal Melbourne Institute of Technology, Melbourne, Victoria 3000, Australia.
authors.forename: W
authors.initials: W
authors.lastname: van Megen