Bosonic flux ladder considering the next nearest neighbor kinetic tunneling

Abstract

We investigate interacting bosons in a two-leg lattice, which is subject to an uniform artificial magnetic field. Its Hamiltonian takes into account the next nearest neighbor kinetic tunneling term, along the principal diagonal direction. With the help of an inhomogeneous dynamical Gutzwiller mean-field theory, we figure out four novel quantum phases of the system site by site, three of which are the dual vortex lattice, the triplet vortex lattice, and the composite vortex lattice. They particularly present parallelogram vortical particle currents, inside those conventional rectangular vortical currents, due to the import of next nearest neighbor kinetic tunneling. Under certain parameters, we further identify the crossed circulation lattice featuring alternating sequences on local currents and occupancies, whose minimal periods are determined by the value of flux quanta.

Keywords

• Chiral vortex currents
• Flux ladder
• Bose–Hubbard model