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arxiv: 2506.15420 · v1 · pith:IWLNQ3NBnew · submitted 2025-06-18 · 🪐 quant-ph

Error-detected coherence metrology of a dual-rail encoded fixed-frequency multimode superconducting qubit

classification 🪐 quant-ph
keywords errordual-railfixed-frequencyarchitectureconversiondecoherenceencodingerror-detected
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Amplitude damping is a dominant source of error in high performance quantum processors. A promising approach in quantum error correction is erasure error conversion, where errors are converted into detectable leakage states. Dual-rail encoding has been shown as a candidate for the conversion of amplitude-damping errors; with unique sensitivities to noise and decoherence sources. Here we present a dual-rail encoding within a single fixed-frequency superconducting multimode transmon qubit. The three island, two junction device comprises two transmonlike modes with a detuning of 0.75-1 GHz, in a coaxial circuit QED architecture. We show the logical bit-flip and phase-flip error rates are more than one order of magnitude lower than the physical error rates, and demonstrate stability and repeatability of the architecture through an extended measurement of three such devices. Finally, we discuss how the error-detected subspace can be used for investigations into the fundamentals of noise and decoherence in fixed-frequency transmon qubits.

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Cited by 4 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Hardware-Efficient Erasure Qubits With Superconducting Transmon Qutrits

    quant-ph 2026-04 unverdicted novelty 7.0

    Transmon qutrits serve as erasure qubits achieving logical T1 over 500 μs with mid-circuit detection, ten times the physical qubit lifetime, plus low-error gates and heralded Bell states.

  2. QMaxCal: Path-Space Regularization for Open Quantum Control via Girsanov's Theorem

    quant-ph 2026-06 unverdicted novelty 6.0

    Derives KL_W and R_DV regularizers from Girsanov's theorem that reduce infidelity by up to 50% and improve robustness to noise mismatch on single- and multi-qubit benchmarks including an IBM Kingston calibration.

  3. The limits of erasure-based postselection for quantum error mitigation

    quant-ph 2026-06 unverdicted novelty 5.0

    Postselection on erasure qubits fully mitigates erasure noise in QFT for erasure-check error rates below 3% and enables dual-rail systems to exceed noise floors unreachable by single-rail at kiloquop scale.

  4. Crosstalk In Contemporary Quantum Devices

    quant-ph 2026-05 unverdicted novelty 1.0

    Review synthesizing crosstalk mechanisms, mitigation strategies, and security vulnerabilities across major quantum computing platforms from existing literature.