Dr hab. Tomasz Zaleski, INTiBS Wrocław

Polish "Nobel Prize" 2015: ultracold atoms. Spectroscopy of ultracold bosons in optical lattices.

Ultracold, trapped atoms are model systems allowing for direct observation of quantum many-body effects. They are of high importance not only for understanding of physics of solids, but also quantum optics, while finding many applications, e.g. in metrology. Owing to precise measurements and direct relation between theoretical description and experimental settings, they are also a perfect tool for validating models and approximations used to describe them. During my talk I will present a method of determining interatomic correlations and calculating dynamic structure factor of ultracold bosons, which can be measured using Bragg spectroscopy. This method uses a pair of laser beams to directly transfer energy and momentum to ultracold atoms allowing for studies of excitation spectra, similarly to angle-resolved photoemission spectroscopy (ARPES) widely used in investigations of solid-state systems.