Optimum protocol for fast-switching free-energy calculations

Autor(en)

Philipp Geiger, Christoph Dellago

Abstrakt

Free-energy differences computed from fast-switching simulations or measurements according to the Jarzynski equation are independent of the particular protocol specifying how the control parameter is changed in time. In contrast, the average work carried out on the system as well the accuracy of the resulting free energy strongly depend on the protocol. Recently, Schmiedl and Seifert [Phys. Rev. Lett. 98, 108301 (2007)] found that protocols that minimize the average work for a given duration of the switching process have discrete steps at the beginning and the end. Here we determine numerically the protocols that minimize the statistical error in the free energy estimate and find that such minimum error protocols have similar discrete jumps. Our analysis shows that the reduction in computational effort achieved by the use of steplike protocols can be considerable. Such large savings of computing time, however, typically occur for parameter ranges in which an application of the Jarzynski equation is impractical due to large statistical errors arising from the exponential work average.

Organisation(en)

Computergestützte Physik und Physik der Weichen Materie

Journal

Physical Review E

Band

81

Anzahl der Seiten

14

ISSN

1539-3755

DOI

https://doi.org/10.1103/PhysRevE.81.021127

Publikationsdatum

2010

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/2fab71a7-5fc6-4eaa-bad1-dc828b74ce31