Quantum degenerate Fermi gas in an orbital optical lattice

Abstract

Spin-polarized samples and spin mixtures of quantum degenerate fermionic atoms are prepared in selected excited Bloch bands of an optical chequerboard square lattice. For the spin-polarized case, extreme band lifetimes above 10 s are observed, reflecting the suppression of collisions by Pauli's exclusion principle. For spin mixtures, lifetimes are reduced by an order of magnitude by two-body collisions between different spin components, but still remarkably large values of about one second are found. By analyzing momentum spectra, we can directly observe the orbital character of the optical lattice. The observations demonstrated here form the basis for exploring the physics of Fermi gases with two paired spin components in orbital optical lattices, including the regime of unitarity.

Controlling higher-orbital quantum phases of ultracold atoms via coupling to optical cavities

“…Recently, fascinating techniques have been proposed to study exotic orbital phenomena, including shaking lattice [12,13] or bipartite-lattice setup [14][15][16][17][18]. Observing Fermi superfluid and strongly correlated Mott-insulating orbital order of ultracold gases, however, is still challenging [19][20][21][22][23][24].…”