**Colloquia 2005**
**THE
FLUCTUATION THEOREM**

Prof.
Denis J. Evans

Australian National University

**Date**

**4-5 p.m., Thursday,
26 May, 2005** .

**Location**

School of Physics
Common Room

Room 64 Old Main Building

The University of New South Wales

**Abstract**

In 1993 we discovered
a relation, subsequently known as the Fluctuation Theorem (FT), which
gives an analytical expression for the probability of observing Second
Law violating dynamical fluctuations in small thermostatted nonequilibrium
systems which are observed for a short period of time. This Theorem
places quantitative restrictions on the operation of small (nano) machines
and devices. These constraints cannot be circumvented.

Quantitative predictions made by the Fluctuation Theorem regarding the
probability of Second Law "violations" have been confirmed
experimentally, both using molecular dynamics computer simulation and
very recently in two laboratory experiments [1] which employed optical
tweezers. In this talk we give a brief summary of the theory [2] and
a description of the experiments.

References

[1] "Experimental demonstration of violations of the Second Law
of Thermodynamics for small systems and short time scales", by
Wang, G.M., Sevick, E.M., Mittag, E., Searles, D.J. and Evans, D.J.,
Phys. Rev. Lett., 89 (5), 050601/1-4 (2002).

[2]"The Fluctuation Theorem" by Denis J Evans and Debra J
Searles, Advances in Physics, 51, 1529-1585(2002).

*The audience,
including graduate students, are invited to meet the speaker 15 minutes
beforehand over wine and cheese in the Physics Common Room.*

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