Erasure Detection in a Superconducting Dual-Rail Qubit with Long-Lived 3D Cavities
ORAL
Abstract
A central challenge in quantum computing is suppressing errors that accumulate during operations and idle times. While full-scale fault-tolerant error correction remains beyond reach, substantial progress can be achieved through architectures combining error mitigation with efficient error detection. Erasure qubits have emerged as a promising approach, where the hardware is designed such that the dominant error can be detected in a way that is quantum non-demolition (QND) on the logical state. The dual-rail qubit offers a powerful realization of an erasure qubit and has been proposed and demonstrated across several platforms, including circuit QED [1,2].
In this work, we realize a superconducting dual-rail erasure qubit optimized for use as a quantum memory. Long-lived quantum memories can play an important role in fault-tolerant quantum algorithms, alleviating temporal and overhead constraints in large-scale computations [3]. Our dual-rail qubit is encoded in two modes of a high-Q 3D TESLA-type cavity [4], with a weakly dispersively coupled transmon ancilla providing the required nonlinearity for logical state preparation and measurement [5]. We demonstrate a mid-circuit erasure-detection protocol that periodically detects leakage from the logical subspace to the $\ket{00}$ state, and present results towards the enhancement of the erasure-detected logical coherence lifetime of our dual-rail qubit.
[1] J. D. Teoh et al., Proceedings of the National Academy of Sciences 120, e2221736120 (2023).
[2] K. S. Chou et al., Nature Physics 20, 1454 (2024).
[3] ´E. Gouzien et al., Phys. Rev. Lett. 127, 140503 (2021).
[4] A. Romanenko et al., Phys. Rev. Lett. 119, 264801 (2017).
[5] O. Milul et al., PRX Quantum 4, 030336 (2023).
In this work, we realize a superconducting dual-rail erasure qubit optimized for use as a quantum memory. Long-lived quantum memories can play an important role in fault-tolerant quantum algorithms, alleviating temporal and overhead constraints in large-scale computations [3]. Our dual-rail qubit is encoded in two modes of a high-Q 3D TESLA-type cavity [4], with a weakly dispersively coupled transmon ancilla providing the required nonlinearity for logical state preparation and measurement [5]. We demonstrate a mid-circuit erasure-detection protocol that periodically detects leakage from the logical subspace to the $\ket{00}$ state, and present results towards the enhancement of the erasure-detected logical coherence lifetime of our dual-rail qubit.
[1] J. D. Teoh et al., Proceedings of the National Academy of Sciences 120, e2221736120 (2023).
[2] K. S. Chou et al., Nature Physics 20, 1454 (2024).
[3] ´E. Gouzien et al., Phys. Rev. Lett. 127, 140503 (2021).
[4] A. Romanenko et al., Phys. Rev. Lett. 119, 264801 (2017).
[5] O. Milul et al., PRX Quantum 4, 030336 (2023).
*We acknowledge financial support from the European Research Council Starting Investigator Grant QCIRC 101040179 and the Minerva Stiftung with funding from the Federal German Ministry for Education and Research
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Presenters
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Tali Shemma
- Weizmann Institute of Science
- Princeton University