论文标题
相关性扩散的相位和组速度在Bose-Hubbard模型的Mott阶段大于一个。
Phase and group velocities for correlation spreading in the Mott phase of the Bose-Hubbard model in dimensions greater than one
论文作者
论文摘要
Lieb-Robinson和相关边界对非相关量子系统中信息传播率设定了上限。在实验上，在量子淬灭之后，在Bose-Hubbard模型中相关性的扩散中观察到了它们。使用最近开发的两个粒子不可固定的（2PI）强耦合方法，用于在Bose-Hubbard模型中取消平衡动力学，从一个，两个和三个维度中分布单粒子相关性作为相互作用强度的函数。我们的结果与测量速度的测量值是定量一致的，该速度是在用超冷原子实现的一维玻色 - 哈伯德模型中分布单个粒子相关性的。他们还同意以下说法：在最近的实验中，在两个维度的实验中观察到了相速度而不是组速度。我们证明，相关扩散的相位和组速度之间可能存在巨大差异，并探索各向异性的变化，即相关性分布在Bose-Hubbard模型的相位图中。我们的结果确定了2PI强耦合方法是一种强大的工具，可以在大于一个的维度中研究Bose-Hubbard模型中的平衡动力学。
Lieb-Robinson and related bounds set an upper limit on the rate of spreading of information in non-relativistic quantum systems. Experimentally, they have been observed in the spreading of correlations in the Bose-Hubbard model after a quantum quench. Using a recently developed two particle irreducible (2PI) strong coupling approach to out-of-equilibrium dynamics in the Bose-Hubbard model we calculate both the group and phase velocities for the spreading of single-particle correlations in one, two and three dimensions as a function of interaction strength. Our results are in quantitative agreement with measurements of the velocities for the spreading of single particle correlations in both the one and two dimensional Bose-Hubbard model realized with ultra-cold atoms. They also agree with the claim that the phase velocity rather than the group velocity was observed in recent experiments in two dimensions. We demonstrate that there can be large differences between the phase and group velocities for the spreading of correlations and also explore the variation of the anisotropy in the velocity at which correlations spread across the phase diagram of the Bose-Hubbard model. Our results establish the 2PI strong coupling approach as a powerful tool to study out-of-equilibrium dynamics in the Bose-Hubbard model in dimensions greater than one.
