Title: Equilibrium Free Energies from Non-Equilibrium Trajectories with Relaxation Fluctuation Spectroscopy
Abstract: Recent advances in non-equilibrium statistical mechanics and single-molecule measurements have enabled the determination of equilibrium free energies from non-equilibrium work measurements for fluctuating systems ranging from biological molecules to quantum oscillators. However, for many important non-equilibrium processes, it is difficult or impossible to apply and measure the work required to drive the system through the relevant conformational changes. In this seminar, I will describe our work to derive and demonstrate a method for the determination of equilibrium free energies, without application or measurement of work. The method, relaxation fluctuation spectroscopy (ReFlucS) works by analyzing the stochastic trajectories of single biomolecules or other nanoscale, fluctuating systems as they spontaneously relax from a non-equilibrium initial state. I will discuss the assumptions required for application of ReFlucS, and its application to the determination of the free-energy profile for DNA molecules in a structured nanofluidic environment. I will also discuss potential extension of the method for determination of energy dissipation rates for non-equilibrium steady-state processes.