Leakage at zero temperature from changes in chemical potential in Majorana qubits

Fuente: arXiv
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Main Authors: Goffage, M. C., Alase, A., Cassidy, M. C., Coppersmith, S. N.
Format: Preprint
Published: 2025
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author Goffage, M. C.
Alase, A.
Cassidy, M. C.
Coppersmith, S. N.
author_facet Goffage, M. C.
Alase, A.
Cassidy, M. C.
Coppersmith, S. N.
contents Building a fault-tolerant quantum computer requires physical qubits with exceptionally low error rates. Majorana-based tetron qubits are predicted to exhibit error rates that decrease exponentially with inverse temperature and length of each topological superconducting wire in the tetron. In contrast to this prediction, we show that errors arising from small variations in the chemical potential grow linearly with tetron length at zero temperature. These errors stem from leakage into excited quasiparticle states, which ultimately poison Majorana modes at opposite ends of the tetron, causing errors. We further demonstrate that the dynamics of this leakage is captured by the half Landau-Zener effect, which dictates its dependence on key system parameters such as the superconducting gap, chemical potential variations, and dynamic changes in the spatial profile of Majorana modes. These results motivate further investigations into the impact of leakage on qubit performance and potential mitigation strategies.
format Preprint
id arxiv_https___arxiv_org_abs_2504_17485
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Leakage at zero temperature from changes in chemical potential in Majorana qubits
Goffage, M. C.
Alase, A.
Cassidy, M. C.
Coppersmith, S. N.
Quantum Physics
Mesoscale and Nanoscale Physics
Building a fault-tolerant quantum computer requires physical qubits with exceptionally low error rates. Majorana-based tetron qubits are predicted to exhibit error rates that decrease exponentially with inverse temperature and length of each topological superconducting wire in the tetron. In contrast to this prediction, we show that errors arising from small variations in the chemical potential grow linearly with tetron length at zero temperature. These errors stem from leakage into excited quasiparticle states, which ultimately poison Majorana modes at opposite ends of the tetron, causing errors. We further demonstrate that the dynamics of this leakage is captured by the half Landau-Zener effect, which dictates its dependence on key system parameters such as the superconducting gap, chemical potential variations, and dynamic changes in the spatial profile of Majorana modes. These results motivate further investigations into the impact of leakage on qubit performance and potential mitigation strategies.
title Leakage at zero temperature from changes in chemical potential in Majorana qubits
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2504.17485