title: Weak additivity principle for current statistics in d dimensions.
abstract: The additivity principle (AP) allows one to compute the current distribution in many one-dimensional nonequilibrium systems. Here we extend this conjecture to general d-dimensional driven diffusive systems, and validate its predictions against both numerical simulations of rare events and microscopic exact calculations of three paradigmatic models of diffusive transport in d=2. Crucially, the existence of a structured current vector field at the fluctuating level, coupled to the local mobility, turns out to be essential to understand current statistics in d>1. We prove that, when compared to the straightforward extension of the AP to high d, the so-called weak AP always yields a better minimizer of the macroscopic fluctuation theory action for current statistics.
authors.affiliation: University of Modena and Reggio Emilia, via G. Campi 213/b, 41125 Modena, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Pérez-Espigares
authors.affiliation: Institute Carlos I for Theoretical and Computational Physics and Departamento de Electromagnetismo y Física de la Materia, Universidad de Granada, 18071 Granada, Spain.
authors.forename: P L
authors.initials: PL
authors.lastname: Garrido
authors.affiliation: Institute Carlos I for Theoretical and Computational Physics and Departamento de Electromagnetismo y Física de la Materia, Universidad de Granada, 18071 Granada, Spain.
authors.forename: P I
authors.initials: PI
authors.lastname: Hurtado