Quantum error correction (QEC) is essential for achieving fault-tolerant quantum computing. While superconducting qubits are among the most promising candidates for scalable QEC, their limited nearest-neighbor connectivity presents significant challenges for implementing a wide range of error correction codes. In this work, we experimentally demonstrate a quantum error detection scheme that employs a dynamically reassigned ancillary qubit on a chain of three linearly connected transmon qubits. We show that this scheme achieves performance comparable to conventional static-ancilla circuits. Additionally, the approach facilitates efficient quantum state preparation, which we demonstrate with tomography of arbitrary logical states. Our results provide a flexible method for implementing QEC codes under connectivity constraints and highlight a promising path toward scalable quantum architectures.
@article{arxiv.2506.20529,
title = {Realization of a Quantum Error Detection Code with a Dynamically Reassigned Ancillary Qubit},
author = {Alena S. Kazmina and Artyom M. Polyanskiy and Elena Yu. Egorova and Nikolay N. Abramov and Daria A. Kalacheva and Viktor B. Lubsanov and Aleksey N. Bolgar and Ilya A. Simakov},
journal= {arXiv preprint arXiv:2506.20529},
year = {2025}
}