GOSSAMER SUPERFLUID AND ANTIFERROMAGNETIC STATE OF COLD ATOMS IN OPTICAL LATTICES

We propose a scheme to simulate the t–J–U model and investigate the quantum phase transitions using cold atoms confined in a two-dimensional optical lattice. By adjusting the parameters of external laser fields, we find a phase transition from antiferromagnetic phase to Gossamer superfluid. The Gossamer superfluid has a d-wave or mixed d- and s-wave symmetry, depending on the hopping parameters which can be adjusted by tuning the laser field. Experimental protocol to observe these new phenomena for future experiments has also been briefly discussed.