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In and out of equilibrium


Albert Einstein's work on brownian motion showed how thermal equilibrium could be brought about by work exchanged through thermal fluctuations and viscous dissipation. Glasses are out-of-equilibrium systems in which this exchange happens at widely different timescales simultaneously. Theory then suggests the fascinating possibility that such behaviour may lead to a more general form of thermalization, in which the effective temperature shared by all components differs at each timescale.

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Figure 1: The two-time (t,t′) correlation C(t,t′) of a typical physical quantity in terms of log(tt′) for two temperatures T1>T2.
Figure 2: M copies of a system (A1, A2,..., AM).
Figure 3: Fluctuation–dissipation plot for a sheared supercooled liquid, taken from ref. 5.


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Kurchan, J. In and out of equilibrium. Nature 433, 222–225 (2005).

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