Accuracy of the electron pump

We calculate the accuracy of the single electron pump numerically and analytically. With a biasing of the device that we describe as optimal, the accuracy is computed with finite temperature cotunneling rates that systematically include all possible cotunneling processes. A simple graphical representation of the operation of the pump illustrates when cotunneling processes become active. We show that the accuracy is limited by cotunneling, thermal activation, and operating the device at too high a frequency; simple approximation formulas are given for these errors. Metrological accuracy is attainable for devices with five or more junctions and with parameters that are experimentally attainable.