Intervenant:  Daniele Fontanari (LMPA Joseph Liouville)
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date:    jeudi 26 mai, 14h, Calais 
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Titre: Quantum mechanics in the phase space: towards a quantum 
-----  Dzhanibekov effect  
Abstract:
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 In a first approximation, found to be in good agreement with
 experimental data, molecules can be described as rigid bodies which,
 from a classical point of view, are characterized by a rich
 geometrical structure and exhibit interesting phenomena
 (integrability, strong anisochronicity, presence of unstable
 equilibria and separatrices...).  The aim of this talk is to
 introduce the classical and the quantum descriptions of the system,
 in order to uncover the correlation between the two frameworks
 through their dynamical similarities.  As a concrete example the
 Dzhanibekov effect, which classically is described by a periodic flip
 of the unstable axis between two unstable equilibrium positions under
 particular initial conditions of the system, is considered. The
 problem of giving a phase space description of the system consistent
 with its quantum nature is addressed and the use of coherent states
 is proposed as a solution.  After the link between classical and
 quantum dynamics has been established, the theoretical (existence of
 different kinds of coherent states) and experimental (creation of a
 coherent state in the laboratory, detection of the quantum state
 after the evolution) challenges that should be faced in the future
 will be briefly introduced.