Current fluctuations in nonequilibrium diffusive systems: An additivity principle

The whole distribution of current fluctuations through a large one-dimensional system in contact with two reservoirs of unequal densities was investigated by developing a simple addivity principle. At the boundaries, the particles were created to match the densities of the reservoirs and the system was evolved under conservative stochastic dynamics. The Gallavotti-Cohen symmetry was satisfied by the distribution which was non-Gaussian and a method for the symmetric simple exclusion process was also generalized by the distribution. It was found that more complex diffusive networks including loops could be studied using the addivity principle.