Revealing topological protection through unprotected operations in a Majorana parity qubit
Abstract
A recent experiment reported coherent parity oscillations between minimal Kitaev chains, demonstrating a Majorana parity qubit (arXiv:2607.09511). Operations on this qubit are controlled by coupling two Kitaev chains and are intrinsically unprotected against noise in the coupling strength. Here we show how the exponential protection in the underlying chains can nevertheless be revealed through unprotected qubit operations. To this end, we develop an analytical theory of quasistatic dephasing for two coupled N-site Kitaev chains at the sweet spot. In Rabi experiments, protection can be resolved by adapting the operating point with chain length: depending on the coupling architecture, it appears as an exponentially increasing optimized number of coherent oscillations or as a longer coherence time. Ramsey experiments show an exponentially increasing coherence time, provided the chains can be sufficiently decoupled. Our analytical theory takes into account the non-Gaussian splitting statistics of the Kitaev chains, allowing us to quantitatively predict the scaling with chain length. Moreover, we determine how residual noise and imperfections limit the range of chain lengths over which this scaling can be observed. Our results show how qubit dynamics can be used to probe Majorana protection in experimentally realistic devices.
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BibTeX
@misc{miles2026revealing,
title = {{Revealing topological protection through unprotected operations in a Majorana parity qubit}},
author = {Sebastian Miles and Juan Daniel Torres Luna and Francesco Zatelli and Nick van Loo and Antonio Lombardi and Vincent P. M. Sietses and Florian J. Bennebroek Evertsz' and Bart Roovers and Leo P. Kouwenhoven and Michael Wimmer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.17198},
eprint = {2610.17198},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.17198},
}
RIS
TY - UNPB
TI - Revealing topological protection through unprotected operations in a Majorana parity qubit
AU - Sebastian Miles
AU - Juan Daniel Torres Luna
AU - Francesco Zatelli
AU - Nick van Loo
AU - Antonio Lombardi
AU - Vincent P. M. Sietses
AU - Florian J. Bennebroek Evertsz'
AU - Bart Roovers
AU - Leo P. Kouwenhoven
AU - Michael Wimmer
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.17198
UR - https://arxiv.org/abs/2610.17198
AB - A recent experiment reported coherent parity oscillations between minimal Kitaev chains, demonstrating a Majorana parity qubit (arXiv:2607.09511). Operations on this qubit are controlled by coupling two Kitaev chains and are intrinsically unprotected against noise in the coupling strength. Here we show how the exponential protection in the underlying chains can nevertheless be revealed through unprotected qubit operations. To this end, we develop an analytical theory of quasistatic dephasing for two coupled N-site Kitaev chains at the sweet spot. In Rabi experiments, protection can be resolved by adapting the operating point with chain length: depending on the coupling architecture, it appears as an exponentially increasing optimized number of coherent oscillations or as a longer coherence time. Ramsey experiments show an exponentially increasing coherence time, provided the chains can be sufficiently decoupled. Our analytical theory takes into account the non-Gaussian splitting statistics of the Kitaev chains, allowing us to quantitatively predict the scaling with chain length. Moreover, we determine how residual noise and imperfections limit the range of chain lengths over which this scaling can be observed. Our results show how qubit dynamics can be used to probe Majorana protection in experimentally realistic devices.
ER -