  Increasing fidelity is the ultimate challenge of quantum information
technology. In addition to decoherence and dissipation, fidelity is affected by
internal imperfections such as impurities in the system. Here we show that the
quality of quantum revival, i.e., periodic recurrence in the time evolution,
can be restored almost completely by coupling the distorted system to an
external field obtained from quantum optimal control theory. We demonstrate the
procedure with wave-packet calculations in both one- and two-dimensional
quantum wells, and analyze the required physical characteristics of the control
field. Our results generally show that the inherent dynamics of a quantum
system can be idealized at an extremely low cost.
