Fluctuation Theorems

It was recently predicted that the average of the work W performed on a system driven between two states is directly related to the corresponding difference in the free energy. This is a rather remarkable result because it suggests a direct relation between non-equlibrium and equilibrium quantities. Aside from fundamental aspects, this so-called Jarzynsky relation may also have practical consequences because non-equilibrium measurements can be performed at rather high speeds. Therefore, this may allow to sample energy landscapes much more efficiently than corresponding equilibrium experiments. For the first time, we investigate the above predictions in the non-Gaussian regime by measuring the applied work, exchanged heat and change in internal energy of a single-colloidal particle driven in a time-dependent non-harmonic potential.


  Distribution of entropy production for a colloidal particle in a nonequilibrium steady state
  T. Speck, V.Blickle, C. Bechinger, U. Seifert
Europhys. Lett. 79, 30002 (2007)
  Thermodynamics of a colloidal particle in a time-dependent non-harmonic potential
  V.Blickle, T. Speck, L. Helden, U. Seifert, C. Bechinger
Phys. Rev. Lett. 96, 070603 (2006)