Physical interpretation of laser-induced suppression of quantum tunneling

We revisit the problem of laser-induced suppression of quantum dynamical tu nneling in a model system studied by Kilin et al. [Phys. Rev. Lett. 76 (199 6) 3297]. This quantum system consists of a ground state symmetric double-w ell potential which is coupled by a strong laser field to an excited state asymmetric double-well potential. By analyzing the assumptions used in thei r analysis we show that the suppression of quantum dynamical tunneling can be explained with the use of dark and bright states of the system. We also generalize the system and the conditions for suppression of quantum tunneli ng and show that, in certain cases, suppression can occur regardless the ch aracteristics of the excited potential surface. (C) 1999 Elsevier Science B .V. All rights reserved.