BEGIN:VCALENDAR VERSION:2.0 PRODID:Icfo X-PUBLISHED-TTL:P1W BEGIN:VEVENT UID:69d4b425698d4 DTSTART:20240429T080000Z SEQUENCE:0 TRANSP:OPAQUE LOCATION:ICFO Auditorium SUMMARY:ICFO | JONATAN HÖSCHELE CLASS:PUBLIC DESCRIPTION:The development of quantum-gas microscopes has revolutionized t he field of quantum simulation with ultracold atoms. More specifically\, t heir ability of direct observation and manipulation of degenerate quantum gases in optical lattices on a single particle level has brought novel way s of probing and engineering quantum degenerate many-body systems. So far\ , most of these setups have focused on alkali atoms. Combining quantum-gas microscopy with the properties of alkaline-earth atoms such as strontium gives rise to exciting research directions. In this thesis\, we report on the design and construction of a strontium quantum-gas microscope. The fin dings in this thesis can be divided into three parts.\nIn the first part\, we focus on the accumulation of atoms in the science cell and develop a s cheme to enhance the atom number in magneto-optical traps of strontium ato ms operating on the 461-nm transition. This scheme resonantly populates a short-lived reservoir state\, partially shielding the atomic cloud from lo sses in the cooling cycle. We demonstrate a factor of 2 enhancement in the atom number for the bosonic isotopes Sr-88 and Sr-84\, and the fermionic isotope Sr-87\, showing the efficient capture of these isotopes in our exp eriment. Our scheme can be readily implemented in the majority of strontiu m experiments\, given that the shielding transition at 689 nm is commonly used for further cooling. In our case\, the shielding scheme facilitates t he generation of Bose-Einstein condensates.\nThe second part of the thesis reports on the generation of degenerate quantum gases of Sr-84 with up to 200000 atoms. After summarizing the required cooling steps\, we study the formation of Bose-Einstein condensates during evaporative cooling in our experiment. Analyzing the evolution of the horizontal and vertical size of our quantum-degenerate clouds in free fall leads to the characteristic as ymmetric expansion\, which we compare to theory for our experimental param eters. We also show the generation of smaller Bose-Einstein condensates of less than 20000 atoms with the help of a light-sheet potential. With this highly-anisotropic confinement we can consider our Bose-Einstein condensa tes two-dimensional for atom numbers of the order of 1000.\nIn the third p art we demonstrate site-resolved imaging of a Sr-84 bosonic quantum gas in a Hubbard-regime optical lattice potential. We confine the quantum gas by a two-dimensional optical lattice and the aforementioned light-sheet pote ntial\, both operating at strontium's clock-magic wavelength. A high-NA im aging objective enables single-atom and single-site resolved fluorescence imaging by scattering photons on strontium's broad 461-nm transition\, whi le performing efficient attractive Sisyphus cooling of the atoms on a narr ower transition at 689 nm. We reconstruct the atomic occupation of the lat tice sites from the fluorescence images\, obtaining imaging fidelities abo ve 94%. Finally\, we realize a Sr-84 superfluid in the Bose-Hubbard regime and observe its characteristic interference pattern after free expansion in the light sheet with single-atom resolution.\nOur strontium quantum-gas microscope provides a new platform to study dissipative Hubbard models an d cooperative effects in atom-light interaction at the microscopic level. Moreover\, the ability to capture also the fermionic isotope Sr-87 paves t he way to generate degenerate Fermi gases with SU(N) symmetry and study SU (N) quantum magnetism.\n \;\nMonday April 29\, 10:00 h. ICFO Auditoriu m\nThesis Director: Prof Dr. Leticia Tarruell DTSTAMP:20260407T073709Z END:VEVENT END:VCALENDAR