Title: "Quantum-gas microscopy of strontium atoms in an optical lattice"

Abstract:

Quantum-gas microscopy is a powerful tool to study individual particle behavior in quantum many-body systems. Realizing those systems with 2-valence electron atoms such as strontium gives rise to exciting phenomena. For example, bosonic strontium in sub-wavelength atomic arrays exhibits strong cooperative effects in atom-photon scattering. The fermionic isotope in the optical lattice enables studying SU(N ≤ 10)-Fermi systems and exotic magnetic phases beyond the limits of natural materials.

We have realized a strontium quantum-gas microscope which will allow us to study these systems experimentally. We produce quantum-degenerate clouds of bosonic strontium by evaporative cooling in an elliptical sheet beam which provides confinement in a two-dimensional plane. We load the gas into a square optical lattice preserving the superfluidity and therefore realizing Hubbard systems. For imaging we pin the atoms in a deep potential and scatter photons at the broad linewidth transition while exploiting the narrow linewidth transition for efficient Sisyphus cooling. We obtain high signal-to-noise-ratio single-site resolved images where the atoms can be imaged for several tens of seconds without observing significant hopping between lattice sites. We have detected a superfluid of ⁸⁴Sr in the optical lattice and are working towards imaging fermions.

Bio:

Sandra Buob is a senior PhD student in the Ultracold Quantum Gases group of Prof. Leticia Tarruell at ICFO. She received her Master’s degree in Physic at ETH Zurich. Currently, she is working on the strontium quantum-gas microscope experiment to study quantum many-body systems on a single particle level. She is interested in Bose and Fermi-Hubbard physics, ultracold atoms and microscopic imaging of these systems.