title: Low-frequency vibrations of soft colloidal glasses.
abstract: We conduct experiments on two-dimensional packings of colloidal thermosensitive hydrogel particles whose packing fraction can be tuned above the jamming transition by varying the temperature. By measuring displacement correlations between particles, we extract the vibrational properties of a corresponding "shadow" system with the same configuration and interactions, but for which the dynamics of the particles are undamped. The vibrational properties are very similar to those predicted for zero-temperature sphere packings and found in atomic and molecular glasses; there is a boson peak at low frequency that shifts to higher frequency as the system is compressed above the jamming transition.
authors.affiliation: Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Chen
authors.forename: Wouter G
authors.initials: WG
authors.lastname: Ellenbroek
authors.forename: Zexin
authors.initials: Z
authors.lastname: Zhang
authors.forename: Daniel T N
authors.initials: DT
authors.lastname: Chen
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Yunker
authors.forename: Silke
authors.initials: S
authors.lastname: Henkes
authors.forename: Carolina
authors.initials: C
authors.lastname: Brito
authors.forename: Olivier
authors.initials: O
authors.lastname: Dauchot
authors.forename: Wim
authors.initials: W
authors.lastname: van Saarloos
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Liu
authors.forename: A G
authors.initials: AG
authors.lastname: Yodh