Controllability of Scattering States of Quantum Mechanical Systems
  This paper provides a framework for the control of quantum mechanical systems with scattering states, i.e., systems with continuous spectra. We present the concept and prove a criterion of the approximate strong smooth controllability. Our results make non-trivial extensions from quantum systems with finite dimensional control Lie algebras to those with infinite dimensions. It also opens up many interesting problems for future studies. 
Re-Bing Wu, Tzyh-Jong Tarn, Chun-Wen Li