Massless Dirac-Weyl fermions in a T3 optical lattice

Abstract

We propose an experimental setup for the observation of quasirelativistic massless fermions. It is based on a T3 optical lattice, realized by three pairs of counterpropagating lasers, filled with fermionic cold atoms. We show that in the long wavelength approximation the T3 Hamiltonian generalizes the Dirac-Weyl Hamiltonian for the honeycomb lattice, however, with a larger value of the pseudospin S=1. In addition to the Dirac cones, the spectrum includes a dispersionless branch of localized states producing a finite jump in the atomic density. Furthermore, implications for the Landau levels are discussed. © 2009 The American Physical Society.