Quasiparticle Solitons in an Extended Bose-Hubbard Dimer Array with Dipolar Interactions

Considering a two-dimensional Bose-Hubbard spinor lattice with weak nearest neighbour interactions and no particle transfer between sites, we theoretically study the transport of energy from one initially excited dimer, to the rest of the lattice. For weak on-site interaction, the excited site’s energy is quickly dispersed throughout the array. However, beyond a critical on-site interaction strength, the excitation becomes self trapped and localized energy breathers and solitons are observed. These are quasiparticle analogues to the discrete two dimensional solitons in photonic lattices. Exact quantum simulations give similar results with the expected smoothing of the transition due to the finite energy variance.