The first form of this relation allows a simple interpretation: the probability flow is proportional to the spatial gradient of the probability density (i.e., in application to \(N >> 1\) similar and ...The first form of this relation allows a simple interpretation: the probability flow is proportional to the spatial gradient of the probability density (i.e., in application to \(N >> 1\) similar and independent particles, just to the gradient of their concentration \(n = Nw\)), with the sign corresponding to the flow from the higher to lower concentrations.