We investigate the ground-state phase diagram of interacting binary Bose gases trapped in two-dimensional optical lattices by means of quantum Monte Carlo simulations. Our simulations reveal a magnetic phase transition from a ferromagnetic-order to a spin insulator inside the Mott insulating phase with two particles per site for quasi-balanced on-site inter- and intra-particle interactions, i.e., . This 3D-XY transition is characterized by the establishment of a finite local magnetic moment along the z-axis, ferromagnetic correlations in the plane and by counterflow superfluidity inside the Mott phase. When decreasing , this transition merges with the Mott-superfluid transition and becomes first order. The merging of the two transitions is investigated with respect to the parameter.

我们通过量子蒙特卡罗模拟研究了二维光学晶格中相互作用的二元玻色气体的基态相图。我们的模拟表明从一磁相变现场间和颗粒内的相互作用，铁磁有序到莫特绝缘相内旋绝缘体与每个站点两个粒子用于准平衡，即，。这种 3D-XY 转变的特点是沿z轴建立了有限的局部磁矩、平面中的铁磁相关性以及莫特相内的逆流超流体。减少时，这种转变与莫特-超流体转变合并成为一阶。关于参数研究两个转换的合并。