Denis Evans' Professional Page.


 

This page includes information which is additional to my official Research School of Chemistry Home Page entry and

to my hiking/bushwalking page at: http://ehrenfest.anu.edu.au/~denis/index.php

Snowgums above Dead Horse Gap (June, 2001).


Statistical Mechanics


We are known for deriving and experimentally confirming the Fluctuation Theorem.

This Theorem gives an elegant extension of the Second Law of Thermodynamics,

so that it applies to finite systems observed for finite times. It also provides the first proof of the Second Law of Thermodynamics - it ceases to be a "Law".

This theorem relates the probabilities of observing time averaged values of a generalized entropy production, namely the dissipation function,

for a period of time, t, equal to an arbitrary value B, relative to -B. This ratio is exponential in the length of the averaging time t, and the number of degrees of freedom in the system - since entropy production is extensive. In the definition of the dissipation function f(G,0) is the initial phase space distribution function dQ/dt is the rate of heat gained or lost per unit time by the system of interest from a thermostat. The thermostat is viewed as being mauch larger than the system of interest and can therefore be regarded as being in thermodynamic eqilibrium at a temperature Tres.

The Theorem resolves the paradox of how time-reversible microscopic dynamics leads, to irreversible macroscopic behaviour. It also implies that as devices are made smaller and smaller the probability that they will run thermodynamically in reverse to what one would expect, increases exponentially with decreasing system size and observation time.

This result is exact for classical systems and quantum anologues are known.

Scientific news articles, popular press and news reports on the Fluctuation Theorem, October 2002.

See also C. Bustamante, J. Liphardt, and F. Ritort, Physics Today, 58, no 7, page 43-48, 2005.

 

The Second Law Inequality is a simple consequence of the Fluctuation Theorem.

It says that the generalized entropy production can be negative but the time average of the ensemble average cannot be negative.

(Searles and Evans, Aust. J. Chem., 57,1119(2004).)

The Dissipation Theorem says that the nonlinear response of an arbitrary phase variable can be calculated from the time integral of the nonequilibrium transient time correlation function of the phase variable with the dissipation function

(Evans, Searles &Williams, J.Chem.Phys., 128, 014504(2008), ibid 128, 249901(2008).):

Finally the Relaxation Theorem says that if an arbitrary initial ensemble of ergodic Hamiltonian systems is in contact with a heat bath and there is a decay of temporal correlations, then the system will at long times, relax to the Maxwell-Boltzmann distribution. Further, this distribution has zero dissipation everywhere in phase space. For such systems no other distribution has zero dissipation everywhere.

Each of these results is exact arbitrarily far from equilibrium and independent of system size.


Liquid State Chemical Physics Research Group

Group members include

Dr Stephen Williams.

Here are two group photos (2001). In the first photo we have from left to right, Owen Jepps (former student), Dr Jerome Delhommelle , Emil Mittag (former student) and Dr Janka Petravic. In the second photo we have Emil, Jerome, Denis and Janka.

The group in 2005. Left to right: James Reid, Stephen Williams and Denis.

We have longstanding and close links with Dr Debra Searles, Griffith University Queensland, and Dr Edie Sevick in the Research School of Chemistry ANU.


CV, lecture notes and publications


Statistical Mechanics of NonEquilibrium Liquids

by Denis J. Evans and Gary P. Morriss

The second edition of my book with Gary Morriss was published in 2008.
Publisher: Cambridge University Press; 2 edition
ISBN-10: 0521857910
ISBN-13: 978-0521857918

The first edition was published by Academic Press, London 1990, Theoretical Chemistry Monograph Series.

The first edition is no longer available from Academic Press. We therefore provide this web version of the book here. The first edition is also available at the Australian National University ePress. The ePress version is available electronically or in a softbound copy for a small fee.

These files are available for personal use only. No bulk reproduction or resale is permitted. The first edition is Copyright © 1990 Denis J. Evans and Gary P. Morriss.

A major review which includes a treatment of molecular fluids is given in:

Sarman S., Evans D.J. and Cummings P.T., "Recent developments in non-Newtonian molecular dynamics", Physics Reports, Elsevier (Ed. M.J. Klein), 305(1-2) 1-92 (1998).


Statistical Mechanics Links. (People, conferences, organisations)


Australia will be hosting Statphys 24, in Cairns Queensland, July 19-23, 2010.
http://www.statphys.org.au/


Links. for students, postdocs and visitors to Canberra.


Movies
My colleague Peter Daivis has generated some neat (QuickTime) movies of tridecane.


 
 

 

 


If you have comments or suggestions, email me at evans@rsc.anu.edu.au


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