Condensed Matter and Statistical Physics Journal Club
| Date: | September 15, 2008 |
| Title: | Failure of the work-Hamiltonian connection for free-energy calculations |
| Speaker: | Malay Bandyopadhyay |
| Reference: | "Failure of the Work-Hamiltonian Connection for Free-Energy Calculations" by Jose M. G. Vilar and J. Miguel Rubi [Phys.Rev.Lett., arXiv:cond-mat.stat-mech] |
| Abstract: | "Extensions of statistical mechanics are routinely being used to infer free energies from the work performed over single-molecule nonequilibrium trajectories. A key element of this approach is the ubiquitous expression dW/dt = ∂H ( x, t )/∂t, which connects the microscopic work W performed by a time-dependent force on the coordinate x with the corresponding Hamiltonian H(x,t) at time t. It is shown that the above mentioned connection cannot be used to estimate free-energy changes. The implications of this result for single-molecule experiments and atomistic molecular simulations are discussed and possible avenues to overcome these limitations has been pointed out." |