TY  - EJOUR
AU  - Besedin, Ilya
AU  - Kerschbaum, Michael
AU  - Knoll, Jonathan
AU  - Hesner, Ian
AU  - Bödeker, Lukas
AU  - Colmenarez, Luis
AU  - Hofele, Luca
AU  - Lacroix, Nathan
AU  - Hellings, Christoph
AU  - Swiadek, François
AU  - Flasby, Alexander
AU  - Panah, Mohsen Bahrami
AU  - Zanuz, Dante Colao
AU  - Müller, Markus
AU  - Wallraff, Andreas
TI  - Realizing Lattice Surgery on Two Distance-Three Repetition Codes with Superconducting Qubits
IS  - arXiv:2501.04612
M1  - FZJ-2025-01517
M1  - arXiv:2501.04612
PY  - 2025
N1  - 19 pages, 13 figures
AB  - Quantum error correction is needed for quantum computers to be capable of fault-tolerantly executing algorithms using hundreds of logical qubits. Recent experiments have demonstrated subthreshold error rates for state preservation of a single logical qubit. In addition, the realization of universal quantum computation requires the implementation of logical entangling gates. Lattice surgery offers a practical approach for implementing such gates, particularly in planar quantum processor layouts. In this work, we demonstrate lattice surgery between two distance-three repetition-code qubits by splitting a single distance-three surface-code qubit. Using a quantum circuit fault-tolerant to bit-flip errors, we achieve an improvement in the value of the decoded $ZZ$ logical two-qubit observable compared to a similar non-encoded circuit. By preparing the surface-code qubit in initial states parametrized by a varying polar angle, we evaluate the performance of the lattice surgery operation for non-cardinal states on the logical Bloch sphere and employ logical two-qubit tomography to reconstruct the Pauli transfer matrix of the operation. In this way, we demonstrate the functional building blocks needed for lattice surgery operations on larger-distance codes based on superconducting circuits.
LB  - PUB:(DE-HGF)25
UR  - https://juser.fz-juelich.de/record/1038532
ER  -