Two-component coupled Bose gas in a 1D optical lattice is examined. In addition to the postulated Mott insulator and superfluid phases, multiple bosonic components manifest spin degrees of freedom. Coupling of the components in the Bose gas leads to substantial changes in the previously observed spin phases, giving rise to a new effective spin Hamiltonian and unraveling remarkable spin correlations. The system in the absence of coupling exhibits ferromagnetic and nonferromagnetic spin phases for on-site intracomponent interaction stronger than intercomponent interaction. Upon introduction of coupling, the phase transition switches from first to second order. For comparable on-site inter- and intracomponent interactions, with coupling, instead of one, two spin phases emerge with a second-order phase transition. Exact diagonalization and variational Monte Carlo with stochastic minimization on the entangled-plaquette state bestow a unique and enhanced perspective on the system beyond the scope of a mean-field treatment.

中文翻译：

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光学晶格中强相互作用的双组分耦合玻色气体

检查一维光学晶格中的双组分耦合玻色气体。除了假定的莫特绝缘体和超流体相之外，多个玻色子分量表现出自旋自由度。Bose 气体中组分的耦合导致先前观察到的自旋相发生重大变化，产生新的有效自旋哈密顿量并解开显着的自旋相关性。在没有耦合的情况下，系统表现出铁磁和非铁磁自旋相，用于现场组件内相互作用强于组件间相互作用。引入耦合后，相变从一阶切换到二阶。对于可比较的现场组件间和组件内相互作用，通过耦合而不是一个，两个自旋相出现二阶相变。