HDR

Mardi 6 Octobre 2026 à 10h30.

Ultrafast photoionization as a probe for isolated quantum systems

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( La présence est nominative; Pour assister à la soutenance, merci de me contacter avant le 22 septembre )

Membres du jury / jury members :

Isabelle COMPAGNON, Professeure des Universités, Université Claude Bernard Lyon 1
Federica AGOSTINI, Chaire Professeure Junior, Sorbonne Université
Thomas PFEIFER, Professeur, Heidelberg University
Marc SIMON, Directeur de Recherche, CNRS
Catalin MIRON, Directeur de Recherche, CEA
Franck LEPINE, Directeur de Recherche, CNRS

Résumé / Abstract :

Pierre Curie first pointed out how lack of symmetries can create new physical phenomena: « C’est la dissymétrie qui crée le phénomène. » With the development of attosecond technologies over the past two decades, it has become possible to study the effect of symmetry or, its lack thereof in light-matter interactions across ultrafast timescales. When molecules in gas phase interact with an attosecond extreme ultraviolet (XUV, wavelength: 10 – 100 nm) pulse, a photoelectron is emitted leaving behind a residual molecular ion. Immediately following the ionization, the photoelectron gets scattered in the potential of the remaining ion delaying its arrival to the detector by a few tens of attoseconds. If one waits a few femtoseconds longer, the heavier nuclei also get a chance to move, making it difficult to differentiate the nuclear motion from the electronic ones in certain situations. On the other hand, in atoms, such ultrashort XUV pulses can drive coherent light-matter interactions via the production of ‘atom + photon’ dressed-states at short wavelengths. For all of these cases, the symmetry of the Hamiltonian describing the process plays a fundamental role in deciding the outcome of the interaction. In this HDR, I will describe the progress made at understanding and manipulating the role of symmetry to control the outcome of such ultrafast light-matter interactions.

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