arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1806.03339cond-mat.dis-nncond-mat.quant-gascond-mat.stat-mech
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具有幂律相互作用的无序自旋链的量子动力学

Quantum dynamics of disordered spin chains with power-law interactions

A. Safavi-Naini, M. L. Wall, O. L. Acevedo, A. M. Rey, R. M. Nandkishore

摘要:

我们使用大量的数值模拟的基础上矩阵乘积态方法来研究自旋链的量子动力学与强就地无序和幂律衰减($1/r^α$)的相互作用。我们专注于两个具有幂律相互作用的自旋$1/2$哈密顿量:海森堡和XY,并使用三种不同的诊断来表征它们相应的长时间动力学:交错磁化模式$I(t)$的衰减、纠缠熵$S(t)$的增长和量子费舍尔信息$F_Q(t).$的增长对于足够快速衰减的相互作用$α>α_c$,我们发现多体局域相,其中$I(t)$饱和到非零值,纠缠熵按$S(t)\propto t^{1/α}$增长,Fisher信息按指数增长。重要的是,纠缠熵和Fisher信息的尺度不一样(不像短程相互作用模型)。XY模型的临界功率$α_c$小于海森堡模型的临界功率。

英文摘要:

We use extensive numerical simulations based on matrix product state methods to study the quantum dynamics of spin chains with strong on-site disorder and power-law decaying ($1/r^α$) interactions. We focus on two spin-$1/2$ Hamiltonians featuring power-law interactions: Heisenberg and XY and characterize their corresponding long-time dynamics using three distinct diagnostics: decay of a staggered magnetization pattern $I(t)$, growth of entanglement entropy $S(t)$, and growth of quantum Fisher information $F_Q(t).$ For sufficiently rapidly decaying interactions $α>α_c$ we find a many-body localized phase, in which $I(t)$ saturates to a non-zero value, entanglement entropy grows as $S(t)\propto t^{1/α}$, and Fisher information grows logarithmically. Importantly, entanglement entropy and Fisher information do not scale the same way (unlike short range interacting models). The critical power $α_c$ is smaller for the XY model than for the Heisenberg model.

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