Stochastic thermodynamics provides a framework for describing small
systems embedded in a heat bath and externally driven to non-equilibrium
[1]. Examples are colloidal particles in time-dependent optical traps,
single biomolecules manipulated by optical tweezers or AFM tips, and
motor proteins driven by ATP excess. A first-law like energy balance
allows to identify applied work, dissipated heat and entropy production
on the level of an individual stochastic trajectory.
For non-equilibrium steady states (NESSs), total entropy production obeys
a detailed fluctuation theorem even for finite times [2]. As an
alternative to the phenomenological approach of introducing an effective
temperature in order to adjust the equilibrium form of the fluctuation-
dissipation theorem (FDT) to a NESS, we have derived a transparent
general form of the FDT in a NESS [3]. Finally, generalized Green-Kubo
relations hold true in NESSs under the weak assumption of local detailed
balance [4]. Where available, these theoretical results will be
illustrated using data from experimental model systems.
[1] U.S., Eur. Phys. J. B, 64, 423, 2008.
[2] U.S., Phys. Rev. Lett. 95, 040602, 2005.
[3] U.S. and T. Speck, EPL 89, 10007, 2010.
[4] U.S., Phys. Rev. Lett. 104, 138101, 2010.