We study quench dynamics in a t-V chain of spinless fermions (equivalent to the spin-$1∕2$ Heisenberg chain) with strong potential disorder. For this prototypical model of many-body localization we have recently argued that—contrary to the established picture—particles do not become fully localized. Here we summarize and expand on our previous results for various entanglement measures such as the number and the Hartley number entropy. We investigate, in particular, possible alternative interpretations of our numerical data. We find that none of these alternative interpretations appears to hold and, in the process, discover further strong evidence for the absence of localization. Furthermore, we obtain more insights into the entanglement dynamics and the particle fluctuations by comparing with non-interacting systems where we derive several strict bounds. We find that renormalized versions of these bounds also hold in the interacting case where they provide support for numerically discovered scaling relations between number and entanglement entropies.

我们研究了无刺费米子的tV链中的淬灭动力学（等效于自旋$\mathrm{1个}∕\mathrm{2个}$海森堡链）具有很强的潜在障碍。对于这种多体定位的原型模型，我们最近认为，与已确定的图片相反，粒子并未完全定位。在这里，我们总结并扩展了我们先前对于各种纠缠度量（例如数量和Hartley数熵）的结果。我们特别研究数字数据的可能替代解释。我们发现这些替代解释都没有成立，并且在此过程中，发现了缺乏本地化的进一步有力证据。此外，通过与推导几个严格界限的非相互作用系统进行比较，我们对纠缠动力学和粒子涨落有了更多的了解。