  Accurate manipulations of an open quantum system require a deep knowledge of
its controllability properties and the information content of the implemented
control fields. By using tools of information and quantum optimal control
theory, we provide analytical bounds (information-time bounds) to characterize
our capability to control the system when subject to arbitrary sources of
noise. Moreover, since the presence of an external noise field induces open
quantum system dynamics, we also show that the results provided by the
information-time bounds are in very good agreement with the Kofman-Kurizki
universal formula describing decoherence processes. Finally, we numerically
test the scaling of the control accuracy as a function of the noise parameters,
by means of the dressed chopped random basis (dCRAB) algorithm for quantum
optimal control.

Quantum Physics