We study the bipartite entanglement as well as the correlation content between two partitions of the quantum 2D Heisenberg model with biquadratic interactions, where the \(\theta \) parameter controls the ratio of the biquadratic and exchange couplings. We also investigate the pairwise entanglement between nearest-neighbor qubits. The calculations were performed for the model on square lattice, in the Néel phase and ferroquadrupolar phase using spin wave theory and Schwinger boson approaches. In the Néel phase that corresponds to range \(-\pi<\theta <0\), we use the Dyson–Maleev representation and SU(2) Schwinger boson representation to calculate the von Neumann entropy as function of the biquadratic coupling \(J_\mathrm{{bq}}\). In the ferroquadrupolar phase, we use the SU(3) Schwinger boson representation which is adequate to treat this phase.

我们研究了具有双二次相互作用的量子二维Heisenberg模型的两部分纠缠以及两个分区之间的相关内容，其中\（\ theta \）参数控制了双二次和交换耦合的比率。我们还研究了最近邻居量子位之间的成对纠缠。使用自旋波理论和Schwinger玻色子方法，在Néel相和铁四极相的方格上对模型进行了计算。在与范围\（-\ pi <\ theta <0 \）对应的Néel相中，我们使用Dyson–Maleev表示和SU（2）Schwinger玻色子表示来计算作为双二次耦合函数的von Neumann熵。 J_ \ mathrm {{bq}} \）。在铁四极相中，我们使用SU（3）Schwinger玻色子表示法足以处理该相。