X-Message-Number: 29403
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From: David Stodolsky <>
Subject: Mesoscopic fluctuations, aging and intermittency in complex d...
Date: Mon, 9 Apr 2007 10:14:36 +0200

Mesoscopic fluctuations, aging and intermittency in complex dynamics

Paolo Sibani

D 317, HC , Copenhagen Univ.

11. apr. 2007 13:15

Resume

The term physical aging was coined nearly three decades ago to  
describe the slow and decelerating changes of physical properties in  
polymers and other soft materials. Spin-glass experiments spurred  
further interest, and aging phenomena have ever since been  
investigated by a large and diverse crowd. Thanks to these efforts,  
aging is now widely recognized to be a general feature of non- 
equilibrium dynamics in complex metastable systems, including e.g.  
type II superconductors, glasses, granular materials, and soft  
condensed matter.

As demonstrated in recent studies of fluctuating signals from  
mesoscopic systems, two types of events may occur in an aging  
systems: reversible, equilibrium-like fluctuations, which produce a  
Gaussian peak with zero average in the Probability Density Function  
(PDF) of the signal, and rare, socalled intermittent events, which  
appear as an exponential tail and may indicate irreversible changes  
from one metastable region, or  valley', in configuration space to a  
different one.

In the talk, I will introduce the topic and discuss a theory of  
intermittency in glassy dynamics. The focus is on the close link  
between record breaking reversible fluctuations on the one side, and  
physically observable intermittent events or  quakes' on the other.  
This idea leads to analytical predictions for the form of the  
fluctuation spectra of the energy, of the autocorrelation functions,  
and of the linear response functions of aging systems. Illustrative  
examples will be given.

Arrang r

Bjarne Andresen





David Stodolsky    Skype: davidstodolsky

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