Europhys. Lett.
Volume 66, Number 2, April 2004
Page(s) 253 - 259
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 April 2004
Europhys. Lett., 66 (2) , pp. 253-259 (2004)
DOI: 10.1209/epl/i2003-10158-3

Intermittency of glassy relaxation and the emergence of a non-equilibrium spontaneous measure in the aging regime

A. Crisanti1, 2 and F. Ritort3, 4

1  Dipartimento di Fisica, Università di Roma "La Sapienza" P.le Aldo Moro 2, I-00185 Roma, Italy
2  Istituto Nazionale Fisica della Materia, Unità di Roma and SMC P.le Aldo Moro 2, I-00185 Roma, Italy
3  Department of Physics, Faculty of Physics, University of Barcelona Diagonal 647, 08028 Barcelona, Spain
4  Department of Physics, University of California - Berkeley, CA 94720, USA

(Received 17 October 2003; accepted in final form 4 February 2004)

We consider heat exchange processes between non-equilibrium aging systems (in their activated regime) and the thermal bath in contact. We discuss a scenario where two different heat exchange processes concur in the overall heat dissipation: a stimulated fast process determined by the temperature of the bath and a spontaneous intermittent process determined by the fact that the system has been prepared in a non-equilibrium state. The latter is described by a probability distribution function (PDF) that has an exponential tail of width given by a parameter $\lambda$, and satisfies a fluctuation theorem (FT) governed by that parameter. The value of $\lambda$ is proportional to the so-called effective temperature, thereby providing a practical way to experimentally measure it by analyzing the PDF of intermittent events.

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

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