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arXiv 0811.1956cond-mat.str-el
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有限磁场和中温下反铁磁S=1/2链的自旋动力学

Spin-Dynamics of the antiferromagnetic S=1/2-Chain at finite magnetic Fields and intermediate Temperatures

S. Grossjohann, W. Brenig

摘要:

本文研究了有限温度和有限磁场下反铁磁自旋1/2海森堡链的动力学结构因子。使用基于随机级数展开和最大熵方法的量子蒙特卡罗方法,我们评估从消失的磁场的纵向和横向动态结构因子达到和超过铁磁饱和的阈值$B_c$,以及高和中等温度。我们研究了场诱导的谱重的重新分布对比纵向与横向激励。在饱和以下的有限领域的无公度低能量模式被发现符合零温度贝特安奈。从横向自旋动力学的角度分析了$B_c$上方的场致铁磁体和$B_c$下方的Luttinger液体之间的交叉。评估和规则,我们评估的质量的分析延续,并表现出良好的最大熵结果的一致性。

英文摘要:

We present a study of the dynamic structure factor of the antiferromagnetic spin-1/2 Heisenberg chain at finite temperatures and finite magnetic fields. Using Quantum-Monte-Carlo based on the stochastic series expansion and Maximum-Entropy methods we evaluate the longitudinal and the transverse dynamic structure factor from vanishing magnetic fields up to and above the threshold $B_c$ for ferromagnetic saturation, as well as for high and for intermediate temperatures. We study the field-induced redistribution of spectral weight contrasting longitudinal versus transverse excitations. At finite fields below saturation incommensurate low-energy modes are found consistent with zero temperature Bethe-Ansatz. The crossover between the field induced ferromagnet above $B_c$ and the Luttinger liquid below $B_c$ is analyzed in terms of the transverse spin-dynamics. Evaluating sum-rules we assess the quality of the analytic continuation and demonstrate excellent consistency of the Maximum-Entropy results.

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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