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  • Open Access

Measurement-Free Quantum Error Correction Optimized for Biased Noise

Katharina Brechtelsbauer1,*, Friederike Butt2,3, David F. Locher2,3, Santiago Higuera Quintero1, Sebastian Weber1, Markus Müller2,3, and Hans Peter Büchler1

  • *Contact author: brechtelsbauer@itp3.uni-stuttgart.de
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PRX Quantum 6, 040349 – Published 1 December, 2025

DOI: https://doi.org/10.1103/wsnf-prwl

Abstract

In this paper, we derive optimized measurement-free protocols for quantum error correction and the implementation of a universal gate set optimized for an error model that is noise biased. The noise bias is adapted for neutral-atom platforms, where two- and multi-qubit gates are realized with Rydberg interactions and are thus expected to be the dominant source of noise. Careful design of the gates allows us to further reduce the noise model to Pauli-Z errors. In addition, the presented circuits are robust to arbitrary single-qubit gate errors, and we demonstrate that the break-even point can be significantly improved compared to fully fault-tolerant measurement-free schemes. The obtained logical qubits with their suppressed error rates on logical gate operations can then be used as building blocks in a first step of error correction in order to push the effective error rates below the threshold of a fully fault-tolerant and scalable quantum error-correction scheme.

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Popular Summary

The ability to perform quantum error correction is a crucial requirement for large-scale quantum computing. However, the successful implementation of quantum error-correction protocols in hardware is challenging. Since each platform comes along with its own challenges, the codesign of quantum error-correction protocols and hardware is an important step toward fault-tolerant quantum computing. In our work we design hardware-specific protocols for neutral-atom platforms.

Neutral-atom platforms offer many useful features that make them promising candidates for quantum computing. One example is the possibility of implementing gates with a strong noise bias, where some error types are more likely to occur than others. A challenge of neutral atoms is slow measurements promoting the accumulation of idling errors.

In our work we account for slow measurements by considering so-called measurement-free quantum error correction, a technique that circumvents midcircuit measurements by implementing feedback with quantum gates. To simplify these measurement-free protocols, we make use of the noise bias assumed for neutral-atom platforms. This allows us to reduce the hardware requirements (e.g., the number of required qubits and gates) and, thus, to come up with schemes that are more realistic for realization in state-of-the-art experimental setups.

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PRX Quantum 6, 040349– Published 1 December, 2025
  • Received 23 May 2025
  • Revised 10 September 2025
  • Accepted 22 October 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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