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arXiv 1201.2844cond-mat.str-el
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可积莫特绝缘体中反常扩散与正常扩散的共存

Coexistence of Anomalous and Normal Diffusion in Integrable Mott Insulators

R. Steinigeweg, J. Herbrych, P. Prelovšek, M. Mierzejewski

摘要:

我们研究了有限动量自旋动力学在一维XXZ自旋链的伊辛型制度在高温下使用密度自相关线性响应理论和实时传播的非平衡密度。而对于不可积模型的结果是很好地符合正常扩散,有限尺寸可积模型揭示了在不同的时间制度的反常和正常扩散的共存。特别是,数值计算结果表明,高斯松弛在最小的非零动量,我们涉及到非零刚度的巨正则系综。对于较大但仍然很小的动量,恢复了正常的扩散。不可穿透粒子模型的类似结果也有助于解决关于可积莫特绝缘体输运的相当矛盾的结论。

英文摘要:

We study the finite-momentum spin dynamics in the one-dimensional XXZ spin chain within the Ising-type regime at high temperatures using density autocorrelations within linear response theory and real-time propagation of nonequilibrium densities. While for the nonintegrable model results are well consistent with normal diffusion, the finite-size integrable model unveils the coexistence of anomalous and normal diffusion in different regimes of time. In particular, numerical results show a Gaussian relaxation at smallest nonzero momenta which we relate to nonzero stiffness in a grand canonical ensemble. For larger but still small momenta normal-like diffusion is recovered. Similar results for the model of impenetrable particles also help to resolve rather conflicting conclusions on transport in integrable Mott insulators.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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