Conservation laws, integrability, and transport in one-dimensional quantum systems
Conservation laws, integrability, and transport in one-dimensional quantum systems
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DOI：
10.1103/physrevb.83.035115
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发表时间：
2011-01-18
影响因子：
3.7
通讯作者：
Affleck, I.
中科院分区：
文献类型：
--
作者：
Sirker, J.;Pereira, R. G.;Affleck, I.
在可积的一维量子系统中，存在着一组无限的局域守恒量，它们可以阻止电流的完全衰减。然而，对于像零磁场下XXZ模型中的自旋电流或半填充下吸引哈伯德模型中的电荷电流这样的情况，电流算符与任何局部守恒量都没有重叠。我们表明，在这些情况下，在有限温度下的运输是占主导地位的扩散贡献与德鲁德重量是小的，甚至为零。对于XXZ模型，我们详细讨论了我们的结果之间的关系，自旋扩散的唯象理论，自旋链化合物的自旋-晶格弛豫率的测量。此外，我们还研究了存在守恒自旋流的Haldane-Shastry模型。
In integrable one-dimensional quantum systems an infinite set of local conserved quantities exists which can prevent a current from decaying completely. For cases like the spin current in the XXZ model at zero magnetic field or the charge current in the attractive Hubbard model at half filling, however, the current operator does not have overlap with any of the local conserved quantities. We show that in these situations transport at finite temperatures is dominated by a diffusive contribution with the Drude weight being either small or even zero. For the XXZ model we discuss in detail the relation between our results, the phenomenological theory of spin diffusion, and measurements of the spin-lattice relaxation rate in spin chain compounds. Furthermore, we study the Haldane-Shastry model where a conserved spin current exists.