AI 中文总结
本研究通过门控反点测量双层石墨烯分母为偶数的FQH态准粒子电荷，观测到$e/4$等电荷，揭示其与非阿贝尔基态兼容，为准粒子局域用于拓扑量子计算提供依据。
AI 中文摘要
测量分母为偶数的分数量子霍尔（FQH）态所承载的准粒子电荷，对确定其基态拓扑结构至关重要。本研究采用双层石墨烯中由门控定义的反点，搭配额外仅控制反点势的门，来测量被困在该反点周围、分母为偶数的FQH态的准粒子电荷。我们在填充因子$\nu=-5/2$、$-1/2$和$3/2$处观测到局域电荷为$e/4$，这与分母为偶数的基态候选方案所预期的最小激发一致；在空穴共轭态$\nu=2/3$处观测到$e/3$。我们进一步表明，增强反点束缚态与延伸边缘态之间的耦合，会驱动两种 regime 之间的交叉，分别以最小激发的门控电压周期和约为该周期两倍的参数为特征。我们讨论了该交叉的两种可能解释：准粒子聚束以及不同反点输运 regime 之间的交叉。结合此前对女儿态的观测，本结果表明双层石墨烯中的分母为偶数的FQH态与非阿贝尔基态兼容，且其准粒子可局域在量子霍尔反点周围，这是拓扑量子计算的必要组成部分。
英文摘要
Measuring the charge of the quasiparticles hosted by even-denominator fractional quantum Hall (FQH) states is essential to identify the topology of their ground state. Here, we use a gate-defined antidot in bilayer graphene, with an additional gate to control only the antidot potential, to measure the charge of the quasiparticles trapped around it in even-denominator FQH states. We observe a localized charge of $e/4$ at $ν=-5/2$, $-1/2$, and $3/2$, consistent with the minimal excitation expected for leading candidate even-denominator ground states, and $e/3$ at the hole-conjugate state $ν=2/3$. We further show that increasing the coupling between the antidot-bound states and extended edge states drives a crossover between two regimes, characterized by the minimal-excitation gate-voltage period and approximately twice that period, respectively. We discuss two possible explanations for this crossover: quasiparticle bunching and a crossover between distinct antidot transport regimes. Our results, together with previous observations of the daughter states, show that the even-denominator FQH states in bilayer graphene are compatible with a non-Abelian ground state, and that their quasiparticles can be localized around a quantum Hall antidot, a necessary ingredient for topological quantum computation.
