Subdiffusive hydrodynamics of nearly integrable anisotropic spin chains.
Subdiffusive hydrodynamics of nearly integrable anisotropic spin chains.
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DOI：
10.1073/pnas.2202823119
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发表时间：
2022-08-23
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
--
作者：
虽然在低维相互作用系统中，电荷输运在低温下是异常的，但在高温下也可能存在强烈的异常。使用量子XXZ自旋链的范例的例子，我们表明，自旋退相或通用额外的哈密顿相互作用的存在下，导致一个广泛的制度subdiffusive自旋运输由于新兴的动力学约束和有效的屏蔽相关的准粒子激发的相互作用。虽然普通的扩散最终恢复在很长一段时间内，扩散常数被证明是非微扰和不连续的函数的外部耦合的强度。我们解决自旋输运易轴海森堡自旋链受到不同的可积性破缺扰动。我们发现subdiffusive自旋输运的动力学指数z = 4的时间尺度参数长的各向异性。在无限各向异性的极限，运输是subdiffusive在所有时间;有限的各向异性，最终恢复扩散在晚些时候，但与扩散常数的扰动的强度无关，仅固定的各向异性的值。我们提供了这些发现的数值证据，我们展示了如何可以理解的相关准粒子激发和有效的动力学约束的动态屏蔽。我们的结果表明，近可积扩散自旋链的扩散常数一般不受可积性破缺强度的微扰。
While charge transport is known to be anomalous at low temperature in low-dimensional interacting systems, strong anomalies can be present at high temperature as well. Using the paradigmatic example of the quantum XXZ spin chain, we show that the presence of spin dephasing or generic additional Hamiltonian interactions leads to a broad regime of subdiffusive spin transport due to the interplay of emergent dynamical constraints and the effective screening of the relevant quasiparticle excitations. Although ordinary diffusion is eventually recovered at long times, the diffusion constant is shown to be nonperturbative and a discontinuous function of the strength of the external couplings. We address spin transport in the easy-axis Heisenberg spin chain subject to different integrability-breaking perturbations. We find subdiffusive spin transport characterized by dynamical exponent z = 4 up to a timescale parametrically long in the anisotropy. In the limit of infinite anisotropy, transport is subdiffusive at all times; for finite anisotropy, one eventually recovers diffusion at late times but with a diffusion constant independent of the strength of the perturbation and solely fixed by the value of the anisotropy. We provide numerical evidence for these findings, and we show how they can be understood in terms of the dynamical screening of the relevant quasiparticle excitations and effective dynamical constraints. Our results show that the diffusion constant of near-integrable diffusive spin chains is generically not perturbative in the integrability-breaking strength.
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影响因子：
8.6
作者：
Lake, B.;Tennant, D. A.;Frost, C. D.
通讯作者：
Frost, C. D.
影响因子：
3.7
作者：
Bastianello, Alvise;De Nardis, Jacopo;De Luca, Andrea
通讯作者：
De Luca, Andrea
影响因子：
8.6
作者：
Bastianello, Alvise;Borla, Umberto;Moroz, Sergej
通讯作者：
Moroz, Sergej
影响因子：
8.6
作者：
Bertini, Bruno;Essler, Fabian H. L.;Robinson, Neil J.
通讯作者：
Robinson, Neil J.
DOI：
10.1088/1742-5468/ac3658
发表时间：
2022-01-01
影响因子：
2.4
作者：
De Nardis, Jacopo;Doyon, Benjamin;Panfil, Milosz
通讯作者：
Panfil, Milosz