相互作用量子点阵列中马约拉纳零模的非微观融合

Bradraj Pandey, Satoshi Okamoto, Elbio Dagotto
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引用次数: 0

摘要

最近有实验报告称量子点系统中的马约拉纳零模(Majorana zero modes,MZMs)处于 "甜蜜点",即电子跳跃th等于超导耦合Δ,受此启发,我们研究了与MZMs非微不足道的融合相对应的随时间变化的光谱学。 术语 "非微不足道 "指的是来自不同原始MZMs对的马约拉纳的融合,每个MZMs对都有明确的奇偶性。我们采用一种可通过实验获得的、与时间相关的实空间局部态密度(LDOS)方法来研究经典链和相互作用电子的 Y 形阵列中的非难 MZM 融合结果。在量子点链中,两对 MZM 最初是断开的,在融合之后,我们发现 LDOS 的电子和空穴分量出现了等高的峰值,这表明非微观融合进入了真空 I 和费米子 Ψ 频道,且权重相等。对于π交界量子点链,超导相在链的左右两侧具有相反的符号,在非微不足道的融合之后,我们观察到在链中心附近形成了奇异的双位点 MZM,并与另一个单位点 MZM 共存。此外,我们还研究了 Y 形几何中三个 MZM 的融合。在这种情况下,我们观察到融合后形成了另一种奇特的多位 MZM,其特性取决于 Y 形量子点阵列中心区域的连接和几何形状。
本文章由计算机程序翻译,如有差异,请以英文原文为准。

Nontrivial fusion of Majorana zero modes in interacting quantum-dot arrays

Nontrivial fusion of Majorana zero modes in interacting quantum-dot arrays
Motivated by recent experimental reports of Majorana zero modes (MZMs) in quantum-dot systems at the “sweet spot,” where the electronic hopping th is equal to the superconducting coupling Δ, we study the time-dependent spectroscopy corresponding to the nontrivial fusion of MZMs. The term “nontrivial” refers to the fusion of Majoranas from different original pairs of MZMs, each with well-defined parities. We employ an experimentally accessible time-dependent real-space local density-of-states (LDOS) method to investigate the nontrivial MZM fusion outcomes in canonical chains and in a Y-shaped array of interacting electrons. In the case of quantum-dot chains where two pairs of MZMs are initially disconnected, after fusion we find equal-height peaks in the electron and hole components of the LDOS, signaling nontrivial fusion into both the vacuum I and fermion Ψ channels with equal weight. For π-junction quantum-dot chains, where the superconducting phase has opposite signs on the left and right portions of the chain, after the nontrivial fusion we observed the formation of an exotic two-site MZM near the center of the chain, coexisting with another single-site MZM. Furthermore, we also studied the fusion of three MZMs in the Y-shaped geometry. In this case, after the fusion we observed the novel formation of another exotic multisite MZM, with properties depending on the connection and geometry of the central region of the Y-shaped quantum-dot array.
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