# Interferometric Single-Shot Parity Measurement in an InAs-Al Hybrid Device

**Authors:** Morteza Aghaee, Alejandro Alcaraz Ramirez, Zulfi Alam, Rizwan Ali, Mariusz Andrzejczuk, Andrey Antipov, Mikhail Astafev, Amin Barzegar, Bela Bauer, Jonathan Becker, Alex Bocharov, Srini Boddapati, David Bohn, Jouri Bommer, Esben Bork Hansen, Leo Bourdet, Arnaud Bousquet, Samuel Boutin, Signe Brynold Markussen, Juan Carlos Estrada Saldaña  
**arXiv:** [2401.09549](https://arxiv.org/abs/2401.09549)  
**Date:** 2024-01-17  
**Summary page:** https://www.summarizepaper.com/fr/paper/2401.09549v2/

## Abstract

The fusion of non-Abelian anyons or topological defects is a fundamental operation in measurement-only topological quantum computation. In topological superconductors, this operation amounts to a determination of the shared fermion parity of Majorana zero modes. As a step towards this, we implement a single-shot interferometric measurement of fermion parity in an indium arsenide-aluminum heterostructure with a gate-defined nanowire. The interferometer is formed by tunnel-coupling the proximitized nanowire to quantum dots. The nanowire causes a state-dependent shift of these quantum dots' quantum capacitance of up to 1 fF. Our quantum capacitance measurements show flux $h/2e$-periodic bimodality with a signal-to-noise ratio of 1 in 3.7 $\mu\text{s}$ at optimal flux values. From the time traces of the quantum capacitance measurements, we extract a dwell time in the two associated states that is longer than 1 ms at in-plane magnetic fields of approximately 2 T. These results are consistent with a measurement of the fermion parity encoded in a pair of Majorana zero modes that are separated by approximately 3 \textmu m and subjected to a low rate of poisoning by non-equilibrium quasiparticles. The large capacitance shift and long poisoning time enable a minimum measurement error probability of $1\%$.