arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1111.4508cond-mat.str-el
收藏

有限温度动力学DMRG和自旋为1/2的链的Drude重量

Finite temperature dynamical DMRG and the Drude weight of spin-1/2 chains

C. Karrasch, J. H. Bardarson, J. E. Moore

摘要:

提出了一种利用密度矩阵重整化群研究有限温度T下一维系统含时关联函数的方法。如果净化统计算子的辅助自由度随物理哈密顿量而时间演化,但逆时间,则任何时间相关计算所固有的纠缠增长将显着减少。我们利用这一点来研究XXZ自旋为1/2的海森堡链的电流关联函数的长时间行为。这允许在中间到大T下直接提取Drude重量D。我们发现,D是非零的-因此运输是无耗散-无处不在的无间隙阶段。在低温下,我们通过与玻色化的比较,建立了D的上界。

英文摘要:

We propose an easily implemented approach to study time-dependent correlation functions of one dimensional systems at finite temperature T using the density matrix renormalization group. The entanglement growth inherent to any time-dependent calculation is significantly reduced if the auxiliary degrees of freedom which purify the statistical operator are time evolved with the physical Hamiltonian but reversed time. We exploit this to investigate the long time behavior of current correlation functions of the XXZ spin-1/2 Heisenberg chain. This allows a direct extraction of the Drude weight D at intermediate to large T. We find that D is nonzero -- and thus transport is dissipationless -- everywhere in the gapless phase. At low temperatures we establish an upper bound to D by comparing with bosonization.

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。

↑