Promotionsvortrag Physik: „Quantum and classical light-matter coupling of Mott insulators“

Ankündigung des Promotionsvortrags von: Herrn Paul Fadler

Mott insulators present an interesting platform to study the dynamics of correlated electrons:
At half filling their charge degree of freedom is frozen due to strong electon-electron repulsions.
This allows for a rich platform to study effective spin and orbital dynamics mediated by charge fluctuations.
Classical and quantum light can be used to measure and manipulate the resulting exchange pro-cesses within these compounds.
In the first half of this talk I show how in the Mott-insulating spin-Peierls compound TiOCl optical pump-probe spectroscopy can access the dynamics of orbitons i.e. quasiparticles consisting of hybrid spin and orbital excitations.

Starting from ab-initio computations I estimate their traces in non-equilibrium spectra using full configuration interaction computations on small clusters.
I furthermore compute their lifetime using Fermi's golden rule on large clusters within an effective spin-orbital description and compare these to the experimental results of double-pump-probe spectroscopy.

Lastly, I show how coupling Mott insulators to quantized light gives rise to long-range spin-spin interactions.
Spin-dependent local charge fluctuations influence the electromagnetic field whose virtual excita-tions act as mediator of long-range spin-spin interactions.

For Mott insulators embedded in a cavity these can play an important role in mesoscopic settings or, if supplemented by an external drive, even in the thermodynamic limit.

(Vortrag auf Englisch)

Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.