Item

Abstract

In recent experiments bosonic [Atala et al., Nat. Phys. 10, 588 (2014); Stuhl et al., Science 349, 1514 (2015)] as well as fermionic ladders [Mancini et al. Science 349, 1510 (2015)] with a uniform flux were studied and different interesting many-body states were observed. Motivated by these experiments, we extend the uniform synthetic magnetic field to a periodic case and show that a commensurate synthetic magnetic field offers an alternative scheme to realize topological phases in many-body systems of ultracold Fermi gases in ladderlike optical lattices. Using the exact diagonalization, we numerically determine the topological band structure, edge states, nonzero Chern numbers, Hofstadter-butterfly-like spectrum, and a complete phase diagram of noninteracting fermionic ladders.