A fermionic triangular-lattice quantum gas microscope

Ultracold atoms in triangular optical lattices provide a versatile platform to study the phase diagram of the triangular-lattice Hubbard model due to the tunability of all relevant parameters. Recently, numerical calculation showed indications for a chiral spin-liquid phase in the transition region between the metallic and ordered magnetic phase which was found to break time-reversal symmetry [1, 2].  Here, we report on the implementation of a projected triangular lattice for ultracold lithium-6 atoms and demonstrate single-atom-resolved imaging via Raman sideband cooling, yielding an imaging fidelity of 98 % [3]. We measure temperatures below one-fifth of the Fermi temperature for Fermi gases before loading into the lattice. For guidance of the experiment, we implemented a numerical linked cluster expansion to calculate finite-temperature correlations in the triangular lattice Hubbard model. Our next plan is to employ our platform to perform theory-experiment comparisons of spin-spin correlations in the Mott-insulating regime and investigate time-reversal symmetry breaking via three-point correlations. [1] A. Szasz, et al., Phys. Rev. X 10, 021042 (2020). [2] B.-B. Chen et. al. arXiv:2102.05560 (2021). [3] J. Yang, et al., arXiv:2102.11862 (2021).