## A note on time-zero controllability and density of orbits for quantum systems

- Andrei A. Agrachev, Ugo V. Boscain, Jean-Paul Gauthier, Mario Sigalotti
- 2017 IEEE 56th Annual Conference on Decision and…
- 2017

- Published 2012 in 2012 IEEE 51st IEEE Conference on Decision and…
DOI:10.1109/CDC.2012.6426208

This note presents an example of bilinear conservative system in an infinite dimensional Hilbert space for which approximate controllability in the Hilbert unit sphere holds for arbitrary small times. This situation is in contrast with the finite dimensional case and is due to the unboundedness of the drift operator.