  Laser control of Open Quantum Systems (OQS) is a challenging issue as
compared to its counterpart in isolated small size molecules, basically due to
very large numbers of degrees of freedom to be accounted for. Such a control
aims at appropriately optimizing decoherence processes of a central two-level
system (a given vibrational mode, for instance) towards its environmental bath
(including, for instance, all other normal modes). A variety of applications
could potentially be envisioned, either to preserve the central system from
decaying (long duration molecular alignment or orientation, qubit decoherence
protection) or, to speed up the information flow towards the bath (efficient
charge or proton transfers in long chain organic compounds). Achieving such
controls require some quantitative measures of decoherence in relation with
memory effects in the bath response, actually given by the degree of
non-Markovianity. Characteristic decoherence rates of a Spin-Boson model are
calculated using a Nakajima-Zwanzig type master equation with converged HEOM
expansion for the memory kernel. It is shown that, by adequately tuning the
two-level transition frequency through a controlled Stark shift produced by an
external laser field, non-Markovianity can be enhanced in a continuous way
leading to a first attempt towards the control of OQS.
