A proportional guidance law for quantum information processing

In this paper, we consider a natural generalisation of classical proportional navigation guidance for quantum information processing devices. We demonstrate how standard guidance laws can be modified to allow the efficient control of the quantum state of an example qubit. We consider an example experimental system: a Josephson charge qubit (Cooper pair box). The quantum guidance algorithm is assessed in an open-loop control system based on the standard bias fields present in the device, without the need for any additional external fields (such as microwave 'pump' fields, which are often used to drive these charge devices into excited states).