Jarzynski equality

The Jarzynski equality, also known as the work relation or non-equilibrium work relation was developed by Chris Jarzynski. According to this equality, the equilibrium Helmholtz energy function of a process, (\(A\)), can be reconstructed by averaging the external work, \(W\), performed in many non-equilibrium realizations of the process (Eq. 2a in ): \[\exp \left( \frac{-\Delta A}{k_BT}\right)= \left\langle \exp \left( \frac{-W}{k_BT} \right) \right\rangle\]

or can be trivially re-written as (Eq. 2b)

\[\Delta A = - k_BT \ln \left\langle \exp \left( \frac{-W}{k_BT} \right) \right\rangle \] where \(k_B\) is the Boltzmann constant and \(T\) is the temperature. The only assumption in the proof of this relation is that of a weak coupling between the system and the reservoir. More recently Jarzynski has re-derived this formula, dispensing with this assumption .

See also

• Crooks fluctuation theorem

References

Related reading

• Gerhard Hummer and Attila Szabo "Free energy reconstruction from nonequilibrium single-molecule pulling experiments", Proceedings of the National Academy of Sciences of the United States of America 98 pp. 3658-3661 (2001)
• E. G. D. Cohen and D. Mauzerall "The Jarzynski equality and the Boltzmann factor", Molecular Physics 103 pp. 2923 - 2926 (2005)
• L. Y. Chen "On the Crooks fluctuation theorem and the Jarzynski equality", Journal of Chemical Physics 129 091101 (2008)
• Eric N. Zimanyi and Robert J. Silbey "The work-Hamiltonian connection and the usefulness of the Jarzynski equality for free energy calculations", Journal of Chemical Physics 130 171102 (2009)
• Humberto Híjar and José M Ortiz de Zárate "Jarzynski's equality illustrated by simple examples", European Journal of Physics 31 pp. 1097 (2010)
• Christopher Jarzynski "Comparison of far-from-equilibrium work relations", Comptes Rendus Physique 8 pp. 495-506 (2007)