Quantum phases in $p$-orbital degenerated attractive 1D fermionic   optical lattices
  We examine quantum phases emerged by double degeneracy of $p$-orbital bands in attractive atomic Fermi gases loaded on a 1D optical lattice. Our numerical simulations by the density-matrix renormalization group predict the emergence of a state with a charge excitation gap, the Haldane insulator phase. A mapping onto an effective spin-$1$ model reveals its physical origin. Moreover, we show that population imbalance leads to richer diversity of the quantum phases, including a phase-separated polarized state. Finally, we study the effects of harmonic trap potential in this 1D chain. 
Keita Kobayashi, Yukihiro Ota, Masahiko Okumura, Susumu Yamada, and   Masahiko Machida
cond-mat.quant-gas