**Laser Control of
Chemical Reactions.**

**Teams primarily involved:**

- CERMICS, ENPC
– Molecular
simulation team (Eric
Cancès)

- Molecular
Photo-physic Laboratory, Université Paris Sud Orsay
(Osman
Atabek)

- System
and Control Center, Ecole des Mines de Paris (Pierre Rouchon)

- Theoretical
Chemistry Laboratory, Université Paris VI (Andreas Savin)

- TAO
Project, INRIA (Marc
Schoenauer)

The objective of the project in this domain
is to increase the contribution of numerical methods for the
control by laser of the evolution of molecular systems in a
quantum microscopic scale. From the practical point of view, the
problem is not necessarily to reach exactly a given state of the
system. In fact a qualitative objective, like for example
orienting a molecule in space in order to prepare the system to
exhibit some behaviour, might be at the same time more reachable
and also more interesting. On the other side the chemists has
observed that the real experiences are (at least currently) much
faster than numerical simulations of Schrödinger equations. This
leads to the idea of **interfacing directly the experience
with an optimization algorithm**.

The very general notion of control in the quantum world lead to many fundamental questions:

- from a
**mathematica**l point of view: which kind of controllability are we talking about? which model is more reasonable to consider? which objective to ask? how to measure our success? - from a
**numerical**point of view: how to corroborate the experience with the computations, how to help experimentalists in their choices of lasers ? how to interpret the results?

Some work has already been done:

C. M. Dion, A. Ben Haj Yedder, E. Cancès, A. Keller, C. Le Bris, and O. Atabek.

*Optimal laser control of orientation: The kicked molecule,*Phys. Rev. A, 65:063408, 2002

G. Turinici, C. LeBris, and H. Rabitz,

*Efficient algorithms for the laboratory discovery of optimal quantum controls*, Phys. Rev. E, 70:016704, 2004.