标题： $X$和$Z$回路测量在马约拉纳四极子器件中的不同寿命 显示英文标题

标题： Distinct Lifetimes for $X$ and $Z$ Loop Measurements in a Majorana Tetron Device

摘要： 我们展示了一种在超导-半导体异质结构中四极子量子位器件的硬件实现和测量结果。 该器件结构包含两条并行的超导纳米线，当调整到拓扑相时，它们支持四个马约拉纳零模（MZMs），以及一个平凡的超导骨架。 通过将超导结构连接到一系列量子点，形成了两个不同的读出干涉仪。 我们对两个环路进行了单次干涉测量，以测量费米子宇称，旨在实现四极子的泡利-$X$和$Z$测量。 进行重复的单次测量得到了两个广泛分离的时间尺度$\tau_X = 14.5\pm 0.3 \, \mathrm{\mu s}$和$\tau_Z = 12.4\pm 0.4\, \mathrm{ms}$，这些时间尺度出现在$X$和$Z$测量环路中，我们将其分别归因于线内宇称切换和外部准粒子污染。 我们分别估计了$\mathrm{err}^X_a=16\%$和$\mathrm{err}^Z_a=0.5\%$对$X$和$Z$基于测量的操作的分配误差。 显示英文摘要

摘要： We present a hardware realization and measurements of a tetron qubit device in a superconductor-semiconductor heterostructure. The device architecture contains two parallel superconducting nanowires, which support four Majorana zero modes (MZMs) when tuned into the topological phase, and a trivial superconducting backbone. Two distinct readout interferometers are formed by connecting the superconducting structure to a series of quantum dots. We perform single-shot interferometric measurements of the fermion parity for the two loops, designed to implement Pauli-$X$ and $Z$ measurements of the tetron. Performing repeated single-shot measurements yields two widely separated time scales $\tau_X = 14.5\pm 0.3 \, \mathrm{\mu s}$ and $\tau_Z = 12.4\pm 0.4\, \mathrm{ms}$ for parity switches observed in the $X$ and $Z$ measurement loops, which we attribute to intra-wire parity switches and external quasiparticle poisoning, respectively. We estimate assignment errors of $\mathrm{err}^X_a=16\%$ and $\mathrm{err}^Z_a=0.5\%$ for $X$ and $Z$ measurement-based operations, respectively.