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

• URL: http://arxiv.org/abs/2507.08795v2
• Date: Thu, 04 Sep 2025 16:57:54 GMT
• Title: Distinct Lifetimes for $X$ and $Z$ Loop Measurements in a Majorana Tetron Device
• Abstract summary: We present a hardware realization and measurements of a tetron qubit device in a superconductor-semiconductor heterostructure.<n>The device architecture contains two parallel superconducting nanowires, which support four Majorana zero modes (MZMs) when tuned into the topological phase.<n>Two distinct readout interferometers are formed by connecting the superconducting structure to a series of quantum dots.
• Score: 18.14892474471491
• License: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Abstract: 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.

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