论文标题

一维质量损害离子哈伯德模型中的淬灭动力学

Quench dynamics in the one-dimensional mass-imbalanced ionic Hubbard model

论文作者

Xie, Zhuotao, Zhao, Ming, Lu, Hantao, Huang, Zhongbing, Fiete, Gregory A., Hu, Xiang, Du, Liang

论文摘要

使用时间依赖性的兰斯佐斯方法,我们研究了由现场库仑相互作用的量子淬火驱动的一维离子质量不平衡的哈币链的非平衡动力学,其中该系统是在汉密尔顿的基础状态制备的,具有不同的hubbard互动。采用了完全精确的对角度化来研究平衡中的零温度相图,该温度相图与以前使用密度矩阵重新归一化组(DMRG)的研究非常吻合。然后,我们通过在更改淬火时间协议的同时固定初始和最终的库仑相互作用来研究自旋和电荷顺序参数的非平衡淬灭动力学。 Lanczos方法使我们在淬火后达到比DMRG更长的时间。我们的研究表明,电荷和旋转顺序参数的时间演变在很大程度上取决于淬火时间协议。特别是,随着淬火时间的增加,系统的有效温度将单调降低。最后,通过将最终的库仑相互作用强度置于强耦合方面,我们发现电荷顺序参数的振荡频率随库仑相互作用而单调增加。相比之下,随着库仑相互作用的增加,自旋顺序参数的频率单调降低。我们使用有效的自旋模型在强耦合极限中解释了这一结果。我们的研究提出了策略,以设计相互作用的量子多粒子系统的放松行为。

Using the time-dependent Lanczos method, we study the non-equilibrium dynamics of the one-dimensional ionic-mass imbalanced Hubbard chain driven by a quantum quench of the on-site Coulomb interaction, where the system is prepared in the ground state of the Hamiltonian with a different Hubbard interaction. A full exact diagonalization is adopted to study the zero temperature phase diagram in equilibrium, which is shown to be in good agreement with previous studies using density matrix renormalization group (DMRG). We then study the non-equilibrium quench dynamics of the spin and charge order parameters by fixing the initial and final Coulomb interaction while changing the quenching time protocols. The Lanczos method allows us to reach longer times following the quench than DMRG. Our study shows that the time evolution of the charge and spin order parameters strongly depend on the quenching time protocols. In particular, the effective temperature of the system will decrease monotonically as the quenching time is increased. Finally, by taking the final Coulomb interaction strength to be in the strong coupling regime, we find that the oscillation frequency of the charge order parameter increases monotonically with the Coulomb interaction. By contrast, the frequency of the spin order parameter decreases monotonically with increasing Coulomb interaction. We explain this result using an effective spin model in the strong coupling limit. Our study suggests strategies to engineer the relaxation behavior of interacting quantum many-particle systems.

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