Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.82: Poster

Mittwoch, 28. März 2007, 14:00–17:45, Poster A

Fermi-edge singularities in the mesoscopic regime — •Martina Hentschel — MPIPKS Dresden, Nöthnitzer Str. 38, 01187 Dresden

Motivated by the experimental progress in the field of mesoscopic physics and quantum chaos over the past years, we study the many-body effects contributing to Fermi-edge singularities in the x-ray edge problem for mesoscopic systems and compare the results with the well-understood metallic case. Upon absorption of an x-ray, a core electron is excited into the conduction band, and the core hole left behind constitutes a sudden, localized perturbation. It entails two counteracting many-body responses, namely Anderson orthogonality catastrophe and Mahan’s exciton, that affect the photoabsorption cross section. Using a rank-one model and a Fermi golden rule approach, we find characteristic deviations from the metallic case that originate in the small system size, mesoscopic fluctuations, and most notably the coherent dynamics of conduction electrons in mesoscopic systems like quantum dots or metallic nanoparticles. We investigate the dependence of the photoabsorption spectra on the number of electrons and argue that our predicitons are observable using nowadays experimental technology.