Are glasses hot ?

Condensed Matter lunchtime seminar

Are glasses hot ?

  • Event time: 1:00pm
  • Event date: 5th November 2007
  • Speaker: (School of Physics & Astronomy, University of Edinburgh)
  • Location: Room 2511,

Event details

By applying the Fluctuation Dissipation Theorem to glasses, theorists (L.F. Cugliandolo, PRE, 55, 3898 (1997); A. Crisanti, J.Phys.A, 36, R181 (2003)) predicted that the dynamical fluctuations of a glass can be characterized by a non-equilibrium temperature. I will present details of an experiment carried out to measure the temperature of a colloidal glass. A micron-sized bead held within the harmonic potential of an optical tweezer forms a microscopic thermometer such that a temperature can be determined by applying the equipartition principle. The thermal motion of a tracer particle suspended in a colloidal material was monitored as the material transformed from a viscous liquid into an elastic glass. Measurements will be discussed in terms of the system dynamics, growth of heterogeneities and the nature of coupling between the probe and the medium. Results confirm the theoretical predictions of an elevated effective temperature in an aging glass.

See: Greinert N., Wood T.A., Bartlett P., Physical Review Letters, 97, 265702, 2006.

About Condensed Matter lunchtime seminars

This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..

Find out more about Condensed Matter lunchtime seminars.