We investigate the leading area-law contribution to entanglement entropy in a system described by a general Lagrangian with $O\left(2\right)$ symmetry containing first- and second-order time derivatives, namely, breaking the Lorentz invariance. We establish a connection between the Higgs gap present in a symmetry-broken phase and the area-law term for the entanglement entropy in the general nonrelativistic case. Our predictions for the entanglement entropy and correlation length are successfully compared to numerical results in two paradigmatic systems: the Mott insulator to the superfluid transition for ultracold lattice bosons and the ground state of ferrimagnetic systems.

中文翻译：

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有限化学势下低能场理论中的纠缠熵

我们研究了由一般拉格朗日方程描述的系统中纠缠熵的主导面积律贡献。 $Ø（2）$包含一阶和二阶时间导数的对称性，即打破洛伦兹不变性。我们建立了对称破缺相中存在的希格斯间隙与一般非相对论情况下纠缠熵的面积定律项之间的联系。我们对纠缠熵和相关长度的预测已成功地与两个范例系统中的数值结果进行了比较：超冷晶格玻色子的Mott绝缘体到超流体跃迁以及亚铁磁系统的基态。