We devise experimental schemes able to mimic uniform and staggered magnetic
fluxes acting on ultracold two-electron atoms, such as ytterbium atoms,
propagating in a honeycomb lattice. The atoms are first trapped into two
independent state-selective triangular lattices and are further exposed to a
suitable configuration of resonant Raman laser beams. These beams induce hops
between the two triangular lattices and make atoms move in a honeycomb lattice.
Atoms traveling around each unit cell of this honeycomb lattice pick up a
nonzero phase. In the uniform case, the artificial magnetic flux sustained by
each cell can reach about two flux quanta, thereby realizing a cold atom
analogue of the Harper model with its notorious Hofstadter's butterfly
structure. Different condensed-matter phenomena such as the relativistic
integer and fractional quantum Hall effects, as observed in graphene samples,
could be targeted with this scheme.Comment: 12 pages, 14 figure
