*Extremal fluctuations and intermittency in aging glassy systems
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The talk considers the statistics of the amount of
heat $Q(\delta t, t, t_w$ exchanged over a short interval
$\delta t$ between a glassy system and its thermal bath.
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The PDF of the heat exchange is studied by numerical
simulations of a short range spin-glass model. Its form
qualitatively depends on the relative magnitude of the sampling
interval $t$ and the system age $t_w$: for $t<
We argue that these events corresponds to the
irreversible release of the excess energy initially trapped by
the quench, and show that their statistics can be interpreted
using a recently advanced theory (P. Sibani and J. Dall, Europhys.
Lett. 64, 8-14, 2003) of non-stationary irreversible relaxation in
glassy systems. The key theoretical assumption there is that
extremal energy fluctuations within metastable regions trigger the
irreversible drift in glassy dynamics.
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* If time permits, the relationship with recent experimental
results on intermittency in aging gels and polymer glasses will
also be discussed.
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