Far-from-equilibrium measurements of thermodynamic length

Journal Article · Wed Nov 05 04:00:00 EST 2008 · Physical Review E

OSTI ID:944530

Feng, Edward H; Crooks, Gavin E

Thermodynamic length is a path function that generalizes the notion of length to the surface of thermodynamic states. Here, we show how to measure thermodynamic length in far-from-equilibrium experiments using the work fluctuation relations. For these microscopic systems, it proves necessary to define the thermodynamic length in terms of the Fisher information. Consequently, the thermodynamic length can be directly related to the magnitude of fluctuations about equilibrium. The work fluctuation relations link the work and the free energy change during an external perturbation on a system. We use this result to determine equilibrium averages at intermediate points of the protocol in which the system is out-of-equilibrium. This allows us to extend Bennett's method to determine the potential of mean force, as well as the thermodynamic length, in single molecule experiments.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Physical Biosciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 944530
• Report Number(s): LBNL-1283E
• Journal Information: Physical Review E, Journal Name: Physical Review E
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
FLUCTUATIONS
FREE ENERGY
THERMODYNAMICS