Scattering in Quantum Lattice Gases

Krzysztof Jachymski, Zbigniew Idziaszek

Xiaoling Cui

We study the effective Bloch-wave scattering of a spinless Fermi gas in one-dimensional (1D) optical lattices. By tuning the odd-wave scattering length, we find multiple resonances of Bloch waves scattering at the bottom (and the top) of the lowest band, beyond which an attractive (and a repulsive) two-body bound state starts to emerge. These resonances exhibit comparable widths in the deep lattice limit, and the finite interaction range plays an essential role in determining their locations. Based on exact two-body solutions, we construct an effective microscopic model for the low-energy scattering of fermions. The model can reproduce not only the scattering amplitudes of Bloch waves at the lowest-band bottom or top, but also the attractive or repulsive bound states within a reasonably large energy range below or above the band. These results lay the foundation for quantum simulating topological states in cold Fermi gases confined in 1D optical lattices.

Peter J. Love

Emek Yesilada

Igor B. Mekhov, Christoph Maschler, Helmut Ritsch

Quantum phases of atoms in optical lattices can be distinguished by light scattering. Atom number distribution functions can be mapped on transmission spectra of a high-Q cavity, allowing QND measurements of atomic variables observing light.

David Clément, Nicole Fabbri, L. Fallani +2 more

We report the Bragg spectroscopy of interacting one-dimensional Bose gases loaded in an optical lattice across the superfluid to the Mott-insulator phase transition. Elementary excitations are created with a nonzero momentum and the response of the correlated 1D gases is in the linear regime. The complexity of the strongly correlated quantum phases is directly displayed in the spectra which exhibit novel features. This work paves the way for a precise characterization of the state of correlated gases in optical lattices.