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arXiv 1709.02740cond-mat.mes-hallcond-mat.str-el
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与杂质自旋耦合的相互作用量子自旋霍尔约瑟夫森结中的$\mathbb{Z}_4$赝费米子

$\mathbb{Z}_4$ Parafermions in an interacting quantum spin Hall Josephson junction coupled to an impurity spin

Yuval Vinkler-Aviv, Piet W. Brouwer, Felix von Oppen

摘要:

$\mathbb{Z}_4$赝费米子可以在强相互作用的量子自旋霍尔约瑟夫森结或与杂质自旋强耦合的自旋霍尔约瑟夫森结中实现。在本文中,我们研究了一个具有这两种特征的系统,但具有弱(排斥)相互作用和弱耦合自旋。我们发现,对于一个强各向异性交换相互作用,在低温下,系统进入一个强耦合极限,其中它主机两个$\mathbb{Z}_4$ parafermion,表征四倍简并的基态。我们明确地构建parafermion运营商,并表明,他们促进分数$e/2$电荷隧道结。有效低能谱对超导相位差的依赖性揭示了超导电流的$8π$周期性。

英文摘要:

$\mathbb{Z}_4$ parafermions can be realized in a strongly interacting quantum spin Hall Josephson junction or in a spin Hall Josephson junction strongly coupled to an impurity spin. In this paper we study a system that has both features, but with weak (repulsive) interactions and a weakly coupled spin. We show that for a strongly anisotropic exchange interaction, at low temperatures the system enters a strong coupling limit in which it hosts two $\mathbb{Z}_4$ parafermions, characterizing a fourfold degeneracy of the ground state. We construct the parafermion operators explicitly, and show that they facilitate fractional $e/2$ charge tunneling across the junction. The dependence of the effective low-energy spectrum on the superconducting phase difference reveals an $8π$ periodicity of the supercurrent.

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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