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北美退伍军人节(Veterans Day),12 日无更新
arXiv 1503.03136cond-mat.supr-con
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超流$^3$ He B相的对称性保护涡旋束缚态

Symmetry protected vortex bound state in superfluid $^3$He B-phase

Yasumasa Tsutsumi, Takuto Kawakami, Ken Shiozaki, Masatoshi Sato, Kazushige Machida

摘要:

由自旋三重态$p$ -波库珀对形成的超流$^3$ He是一种典型的拓扑超流。在超流$^3$ He B相中,产生了几种按空间对称性分类的涡旋:$P_1$、$P_2$和$P_3$,其中$P_1$是反演对称,$P_2$是磁反射对称,$P_3$是磁$π$ -旋转对称.我们用Bogoliubov-de Gennes理论和准经典Eilenberger理论计算了涡旋束缚态,阐明了空间对称性对低能激发态的对称性保护。在对称性保护方面,$P_3$对称性起着关键作用,它给出了二重简并的Majorana零模。在具有$P_1$、$P_2$和$P_3$对称性的最对称$o$涡旋和具有$P_3$对称性的$w$涡旋中,束缚态具有对称性保护的简并Majorana零模.另一方面,在$v$涡旋中的零能量模式(其被认为在实际B相中实现)未被保护,并且因此通过破坏轴对称而变得有间隙。激发能隙可以作为临界速度的变化而观察到。我们还提出了一个实验装置,通过约束和磁场来产生具有Majorana零模的$o$涡旋。

英文摘要:

The superfluid $^3$He formed by spin-triplet $p$-wave Cooper pairs is a typical topological superfluid. In the superfluid $^3$He B-phase, several kinds of vortices classified by spatial symmetries $P_1$, $P_2$, and $P_3$ are produced, where $P_1$ is inversion symmetry, $P_2$ is magnetic reflection symmetry, and $P_3$ is magnetic $π$-rotation symmetry. We have calculated the vortex bound states by the Bogoliubov-de Gennes theory and the quasiclassical Eilenberger theory, and also clarified symmetry protection of the low energy excitations by the spatial symmetries. On the symmetry protection, $P_3$ symmetry plays a key role which gives two-fold degenerate Majorana zero modes. Then, the bound states in the most symmetric $o$ vortex with $P_1$, $P_2$, and $P_3$ symmetries and in $w$ vortex with $P_3$ symmetry have the symmetry protected degenerate Majorana zero modes. On the other hand, zero energy modes in $v$ vortex, which is believed to be realized in the actual B-phase, are not protected, and in consequence become gapped by breaking axial symmetry. The excitation gap may have been observed as the variation of critical velocity. We have also suggested an experimental setup to create $o$ vortex with Majorana zero modes by a confinement and a magnetic field.

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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