Title of the Thesis:
“Diagrammatic Monte Carlo for Fröhlich, acoustic and quadratic polaronsPhonon-assisted driving of quantum dot single-photon sources and its applications in quantum cryptography”
Defense committee:
Mikhail Lemeshko, Institute of Sciene and Technology Austria, AR (reviewer)
Darko Tanaskovic, Institute of Physics Belgrade, RS (reviewer)
Cesare Franchini (supervisor)
Thomas Pichler (chair)
Abstract:
Polarons, quasiparticles formed by electrons interacting with lattice vibrations, play a central role in the transport, optical, and superconducting properties of many condensed matter systems. Understanding their behavior across coupling regimes and interaction mechanisms remains a major challenge in theoretical condensed matter physics. This thesis presents theoretical and numerical investigations of several polaron models using the Diagrammatic Monte Carlo (DiagMC) method, focusing on three representative cases in electron-phonon physics: the Fröhlich large polaron, the acoustic lattice polaron with deformation- potential coupling, and the quadratic polaron. For each model we examine ground-state properties, effective masses, and spectral features, exploring how different coupling mechanisms shape quasiparticle behavior across weak, intermediate, and strong coupling regimes. The results provide new benchmarks for the polaron community and contribute to the understanding of electron-phonon physics in polarizable materials.
