Volume 79, Number 2, July 2007
Article Number 26001
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 21 June 2007
EPL, 79 (2007) 26001
DOI: 10.1209/0295-5075/79/26001

Driven activation vs. thermal activation

P. Ilg1 and J.-L. Barrat2

1  ETH Zürich, Polymer Physics, HCI H541 - CH-8093 Zürich, Switzerland
2  Université Lyon I, Laboratoire de Physique de la Matière Condensée et des Nanostructures; CNRS, UMR 5586 43 Bvd. du 11 Novembre 1918, 69622 Villeurbanne Cedex, France

received 10 April 2007; accepted in final form 31 May 2007; published July 2007
published online 21 June 2007

Activated dynamics in a glassy system undergoing steady shear deformation is studied by numerical simulations. Our results show that the external driving force has a strong influence on the barrier crossing rate, even though the reaction coordinate is only weakly coupled to the nonequilibrium system. This "driven activation" can be quantified by introducing in the Arrhenius expression an effective temperature, which is close to the one determined from the fluctuation-dissipation relation. This conclusion is supported by analytical results for a simplified model system.

64.70.Pf - Glass transitions.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
05.70.Ln - Nonequilibrium and irreversible thermodynamics.

© Europhysics Letters Association 2007