Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits
Journal article, 2026
On-demand qubit-state initialization is a prerequisite for quantum computation. We demonstrate such a protocol in a device consisting of fixed-frequency transmon qubits pair-wise coupled via tunable couplers - an architecture that is also compatible with the surface code. We use tunable couplers to transfer any undesired qubit excitation to the readout resonator of the qubit, from which this excitation decays into the feedline. In total, the combination of multi-level qubit reset, leakage reduction, and coupler reset takes only 88 ns to complete. Our reset scheme is fast, unconditional, and achieves fidelities above 99%, thus enabling fixed-frequency qubit architectures as future implementations of fault-tolerant quantum computers.
Author
Liangyu Chen
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Simon Pettersson Fors
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
Zixian Yan
Chalmers, Microtechnology and Nanoscience (MC2)
Anaida Ali
Chalmers, Microtechnology and Nanoscience (MC2)
Tahereh Abad
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
Tangyou Huang
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Amr Osman
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Eleftherios Moschandreou
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Benjamin Lienhard
Princeton University
Sandoko Kosen
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Hang-Xi Li
Chalmers, Microtechnology and Nanoscience (MC2)
Daryoush Shiri
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Tong Liu
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Stefan Hill
Chalmers Next Labs AB
Abdullah-Al Amin
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Robert Rehammar
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Mamta Dahiya
Chalmers, Microtechnology and Nanoscience (MC2)
Andreas Nylander
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Marcus Rommel
Chalmers, Microtechnology and Nanoscience (MC2), Nanofabrication Laboratory
Anita Fadavi Roudsari
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Marco Caputo
Technical Research Centre of Finland (VTT)
Leif Gronberg
Technical Research Centre of Finland (VTT)
Joonas Govenius
Technical Research Centre of Finland (VTT)
Miroslav Dobsicek
Chalmers Next Labs AB
Michele Faucci Giannelli
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Anton Frisk Kockum
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
Jonas Bylander
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Giovanna Sammarco Tancredi
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
NPJ QUANTUM INFORMATION
2056-6387 (eISSN)
Vol. 12 1 135Green Fuel Stack
Knut and Alice Wallenberg Foundation (2023.0161), 2023-05-01 -- 2024-04-30.
Knut and Alice Wallenberg Foundation (2025.0183), 2025-03-01 -- 2026-03-30.
Subject Categories (SSIF 2025)
Other Physics Topics
DOI
10.1038/s41534-026-01356-2