Hardware-Efficient Erasure Qubits With Superconducting Transmon Qutrits

Quantum Physics [Submitted on 9 Apr 2026] Hardware-Efficient Erasure Qubits With Superconducting Transmon Qutrits Bao-Jie Liu, Ying-Ying Wang, Yu-Xin Wang, Manthan Badbaria, Shruti Puri, Chen Wang Quantum error correction using erasure qubits offers higher fault-tolerant thresholds and improved scaling by converting dominant physical errors into detectable erasures. In superconducting circuits, erasure qubits can be constructed using the dual-rail approach, which, however, requires additional qubit-count overhead and tailored coupling elements. Here, we demonstrate a hardware-efficient scheme that operates transmon qutrits as erasure qubits, which is compatible with standard superconducting circuit-QED hardware. The logical states \ket{0_\text{L}}$\ket{0_\text{L}}$ and \ket{1_\text{L}}$\ket{1_\text{L}}$ are represented by the ground and second excited states, while the dominant relaxation errors can be detected via an ancilla qubit using a microwave-activated two-qutrit SWAP gate. We demonstrate a logical qubit T_1 lifetime exceeding 500\,\mu\mathrm{s}, post-selected with repeated mid-circuit erasure detection, which is ten times longer than the T_1 time of the transmon physical qubit. Coherence times beyond 300\,\mu\mathrm{s} are achieved using dynamical decoupling. Single-qubit gate operations reach average Clifford gate infidelity on the order of 10^{-4}. We further demonstrate dual-purposing an ancilla qubit for both erasure detection and parity checking, showing heralded generation of Bell states between erasure qubits. These results suggest that mainstream architectures of transmon qubit arrays may already be capable of implementing erasure-based QEC strategies for hardware-efficient fault-tolerant quantum computing. Comments: 9+9pages Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.08672 [quant-ph]   (or arXiv:2604.08672v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.08672 Focus to learn more Submission history From: Bao-Jie Liu [view email] [v1] Thu, 9 Apr 2026 18:01:53 UTC (7,993 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)