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arXiv 0902.4385cond-mat.str-el
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介观量子环中持续电流的大系统渐近性

The large system asymptotics of persistent currents in mesoscopic quantum rings

A. Gendiar, R. Krcmar, M. Weyrauch

摘要:

我们考虑一个充满无自旋电子的一维介观量子环,环中有一个磁通量穿过,该磁通量在零温度下携带持续电流。库仑相互作用和一个单一的现场杂质的相互作用产生的环的大小上的持续电流的非平凡的依赖。我们确定数值系统的渐近幂律高达32000个网站的各种杂质的强度和比较与预测从贝特Anglands解决方案结合玻色化。数值结果是用改进的泛函重整化群(fRG)方法得到的。我们应用密度矩阵重整化群(DMRG)和精确对角化方法对fRG计算进行基准测试。我们使用DMRG来研究低电子浓度下的持续电流,以便将我们的结果的有效性扩展到准连续系统。我们简要地评论的质量计算fRG基态能量与精确的DMRG数据进行比较。

英文摘要:

We consider a one-dimensional mesoscopic quantum ring filled with spinless electrons and threaded by a magnetic flux, which carries a persistent current at zero temperature. The interplay of Coulomb interactions and a single on-site impurity yields a non-trivial dependence of the persistent current on the size of the ring. We determine numerically the asymptotic power law for systems up to 32000 sites for various impurity strengths and compare with predictions from Bethe Ansatz solutions combined with Bosonization. The numerical results are obtained using an improved functional renormalization group (fRG) method. We apply the density matrix renormalization group (DMRG) and exact diagonalization methods to benchmark the fRG calculations. We use DMRG to study the persistent current at low electron concentrations in order to extend the validity of our results to quasi-continuous systems. We briefly comment on the quality of calculated fRG ground state energies by comparison with exact DMRG data.

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