Bound state and time evolution for single excitation in one dimensional XXZspin chain within non-Markovian reservoir are studied exactly. As for boundstate, a common feature is the localization of single excitation, which meansthe spontaneous emission of excitation into reservoir is prohibited.Exceptionally the pseudo-bound state can always be found, for which the singleexcitation has a finite probability emitted into reservoir. We argue that underlimit $N\rightarrow \infty$ the pseudo-bound bound state characterizes anequilibrium between the localization in spin chain and spontaneous emissioninto reservoir. In addition, a critical energy scale for bound states is alsoidentified, below which only one bound state exists and it also is pseudo-boundstate. The effect of quasirandom disorder is also discussed. It is found inthis case that the single excitation is more inclined to locate at some spinsites. Thus a many-body-localization like behavior can be found. In order todisplay the effect of bound state and disorder on the preservation of quantuminformation, the time evolution of single excitation in spin chain studiedexactly by numerically solving the evolution equation. A striking observationis that the excitation can be stayed at its initial location with a probabilitymore than 0.9 when the bound state and disorder coexist. However if any one ofthe two issues is absent, the information of initial state can be erasedcompletely or becomes mixed. Our finding shows that the combination of boundstate and disorder can provide an ideal mechanism for quantum memory.
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机译：精确研究了非马尔可夫油藏中一维XXZspin链中单激发的束缚态和时间演化。对于束缚态，一个共同的特征是单激发的局域性，这意味着禁止将激发的自发发射到储层中，但总是可以找到伪束缚态，对于这种情况，单激发具有有限的概率被发射到储层中。我们认为，下界$ N \ rightarrow \ infty $的伪束缚状态表征了自旋链中的定位与自发注入储层之间的平衡。此外，还确定了用于结合态的临界能级，在该能级以下仅存在一个结合态，它也是伪结合态。还讨论了准随机性障碍的影响。在这种情况下，发现单个激发更倾向于位于某些自旋点。因此，可以发现类似多体定位的行为。为了显示束缚态和无序状态对量子信息保存的影响，通过数值求解演化方程，精确研究了自旋链中单激发的时间演化。令人惊讶的观察是，当结合状态和无序共存时，激发可以以大于0.9的概率停留在其初始位置。但是，如果两个问题中的任何一个都不存在，则初始状态的信息可以被完全擦除或混合在一起。我们的发现表明，结合态和无序可以为量子记忆提供理想的机制。
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