Low-Temperature Phases in Two-Orbital Hubbard Model Realized with Ultracold Atoms in Optical Lattices
A. Sotnikova, Y. Zambranob, A. Cichyb, c
aAkhiezer Institute for Theoretical Physics, NSC KIPT, Akademichna 1, 61108 Kharkiv, Ukraine
bFaculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, PL-61-614 Poznań, Poland
cInstitut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 9, D-55099 Mainz, Germany
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We study ultracold quantum gases of alkaline-earth-like atoms loaded into three-dimensional state-dependent optical lattice. In particular, we focus on the fermionic ytterbium-173 atoms due to their unique properties, in particular, low-lying metastable excited e electronic state, decoupling of the nuclear spin from the electronic degrees of freedom and different AC-polarizabilities of the ground g and e states. This allows to realize the two-band Hubbard model and study its unique critical properties. The theoretical analysis is performed in the region of applicability of the tight-binding approximation at different lattice depths and different fillings by atoms in the g- and e-orbital states. By means of dynamical mean-field theory, we analyze stability regions of the emerging ordered phases.

DOI:10.12693/APhysPolA.138.669
topics: Ultracold atoms, optical lattices, two-band Hubbard model, ytterbium, ferromagnetism, orbital ordering