Multiple path adiabatic crossing in a three-site ring

We find an exact expression for the current that is induced in a three-site ring during a multiple-path adiabatic crossing. The understanding of the dynamics requires us to go beyond the two-level phenomenology. In particular we highlight a prototype process, 'adiabatic metamorphosis', during which current is flowing through a non-accessible site. This helps to understand the crossover from coherent non-classical splitting to stochastic noisy-alike partitioning of the current.