title: Detecting nonlinear and many-body dynamics in nuclear quantum optics creator: Wolff, Lukas Robert Gustav subject: ddc-530 subject: 530 Physics description: In this thesis, different measurement and data evaluation approaches for the detection and characterization of collective nuclear level schemes arising in the low-excitation regime of thin-film x-ray cavities are discussed. The first approach uses Fourier transforms to analyze time- and frequency-resolved spectra recorded using nuclear reference absorbers. This allows for the extraction of the phase-resolved nuclear resonant response of the sample under investigation. Next, to study the dynamics of nuclear ensembles upon suitably-shaped x-ray light, a density matrix perturbation theory is presented that allows for the study of multi-level and many-body dynamics in the low-excitation regime of the x-ray-nuclei interaction. This method is used to interpret numerical data simulating several experimental scenarios: First, it is used to derive an equivalence between coherently and incoherently scattered x-ray intensity detectable in nuclear resonant scattering experiments, which serves as a criterion for nonlinear excitation of nuclear ensembles at coherent x-ray sources. Second, signatures of couplings between collective excited nuclear states in thin-film cavities upon differently-shaped x-ray pulses are proposed and identified in time-frequency-spectra. Finally, the feasibility of a specific coherent double pulse spectroscopic method under low-excitation conditions is discussed and numerically simulated spectra upon different double pulse sequences are compared. date: 2023 type: Dissertation type: info:eu-repo/semantics/doctoralThesis type: NonPeerReviewed format: application/pdf identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/34089/1/PhDThesis_LukasWolff.pdf identifier: DOI:10.11588/heidok.00034089 identifier: urn:nbn:de:bsz:16-heidok-340898 identifier: Wolff, Lukas Robert Gustav (2023) Detecting nonlinear and many-body dynamics in nuclear quantum optics. [Dissertation] relation: https://archiv.ub.uni-heidelberg.de/volltextserver/34089/ rights: info:eu-repo/semantics/openAccess rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html language: eng