Rostock 2019 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 25: Poster: Quantum Optics and Photonics I
Q 25.20: Poster
Tuesday, March 12, 2019, 16:30–18:30, S Atrium Informatik
Lifetime of a chiral superfluid in an orbital optical lattice — •Max Hachmann1, Raphael Eichberger1,2, Robert Büchner1, and Andreas Hemmerich1,2 — 1Institut für Laserphysik — 2The Hamburg Center for Ultrafast Imaging
We study bosons in metastable higher bands of an optical square lattice, where the composition of local orbitals with different nodal geometry and orientation can lead to wavefunctions with highly complex patterns of the local phase. In the second band the ground state wavefunction comprises local px and py-orbitals. If the lattice beams are precisely controlled to provide 4-fold rotation symmetry, px and py-orbitals are degenerate and repulsive interaction favors a complex superposition px± i py. Hence, a complex wavefunction arises with a staggered vortex phase pattern. If due to lattice imperfections a small energy difference on the order of several nanokelvin of px and py-orbitals is adjusted, only the energetically lower of the p-orbitals is populated and a real striped phase pattern arises. We present a novel optical lattice setup, which utilizes a Michelson-Sagnac interferometer. It enables the excitation to higher bands and a precise control of even fine details of the bandstructure. The lifetime of excited metastable states in higher bands is limited by binary collisions and depends sensitively on the details of the band structure. Close to px± i py-order the lifetime is expected to signiffcantly increase due to negative interference of different relaxation channels. We report first measurements demonstrating this effect.