Giorgio Benedek

Professor , University of Milano-Bicocca, Italy

Giorgio Benedek is a theoretical condensed-matter physicist, emeritus professor of Physics of Matter at the University of Milano-Bicocca, director of the International School of Solid State Physics at the EMFCSC in Erice, and visiting professor at the DIPC in San Sebastian.

​The collaboration of Benedek with Jan Peter Toennies (MPI-DS, Göttingen) led to a full development of the surface-phonon spectroscopy with Helium Atom Scattering (HAS) for different classes of materials. Within this collaboration, Benedek and coworkers predicted or explained several inelastic HAS effects like the kinematical focusing, the anomalous longitudinal resonance, the inelastic bound-state resonance-enhancement and the quantum sonar effect, by which HAS from a conducting surface can detect deep subsurface phonons via the electron-phonon interaction.

​More recently, that collaboration, extended at the DIPC to J. R. Manson, S. Miret-Artès proved the possibility to directly measure with HAS the electron-phonon interaction in a wide class of conducting surfaces. The collaboration with J. Peter Toennies and other colleagues also lead to the formulation of a vibronic theory of molecules trapped in nanometric 4He droplets that confirmed the cluster superfluidity on the atomic scale. Moreover, his analysis of the geyser effect observed by Toennies in vacuum expansion from a 4He solid provided evidence of condensation of excess vacancies causing a superfluid flow of solid 4He.