Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits

Liangyu Chen; Simon Pettersson Fors; Zixian Yan; Anaida Ali; Tahereh Abad; Tangyou Huang; Amr Osman; Eleftherios Moschandreou; Benjamin Lienhard; Sandoko Kosen; Hang Xi Li; Daryoush Shiri; Tong Liu; Stefan Hill; Abdullah Al Amin; Robert Rehammar; Mamta Dahiya; Andreas Nylander; Marcus Rommel; Anita Fadavi Roudsari; Marco Caputo; Leif Grönberg; Joonas Govenius; Miroslav Dobsicek; Michele Faucci Giannelli; Anton Frisk Kockum; Jonas Bylander; Giovanna Tancredi

doi:10.1038/s41534-026-01356-2

Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits

Liangyu Chen^*
, Simon Pettersson Fors
, Zixian Yan
, Anaida Ali
, Tahereh Abad
, Tangyou Huang
, Amr Osman
, Eleftherios Moschandreou
, Benjamin Lienhard
, Sandoko Kosen
, Hang Xi Li
, Daryoush Shiri
, Tong Liu
, Stefan Hill
, Abdullah Al Amin
, Robert Rehammar
, Mamta Dahiya
, Andreas Nylander
, Marcus Rommel
, Anita Fadavi Roudsari

Marco Caputo, Leif Grönberg, Joonas Govenius, Miroslav Dobsicek, Michele Faucci Giannelli, Anton Frisk Kockum, Jonas Bylander^*, Giovanna Tancredi^*

^*Corresponding author for this work

Chalmers University of Technology
Princeton University

Research output: Contribution to journal › Article › Scientific › peer-review

Abstract

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.

Original language	English
Article number	135
Journal	NPJ Quantum Information
Volume	12
DOIs	https://doi.org/10.1038/s41534-026-01356-2
Publication status	Published - Dec 2026
MoE publication type	A1 Journal article-refereed

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Chen, L., Fors, S. P., Yan, Z., Ali, A., Abad, T., Huang, T., Osman, A., Moschandreou, E., Lienhard, B., Kosen, S., Li, H. X., Shiri, D., Liu, T., Hill, S., Amin, A. A., Rehammar, R., Dahiya, M., Nylander, A., Rommel, M., ... Tancredi, G. (2026). Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits. NPJ Quantum Information, 12, Article 135. https://doi.org/10.1038/s41534-026-01356-2

@article{1cc9960872fb470ca4dfa6dfb66c7c7d,

title = "Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits",

abstract = "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 {\textemdash} 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 and Fors, \{Simon Pettersson\} and Zixian Yan and Anaida Ali and Tahereh Abad and Tangyou Huang and Amr Osman and Eleftherios Moschandreou and Benjamin Lienhard and Sandoko Kosen and Li, \{Hang Xi\} and Daryoush Shiri and Tong Liu and Stefan Hill and Amin, \{Abdullah Al\} and Robert Rehammar and Mamta Dahiya and Andreas Nylander and Marcus Rommel and Roudsari, \{Anita Fadavi\} and Marco Caputo and Leif Gr{\"o}nberg and Joonas Govenius and Miroslav Dobsicek and Giannelli, \{Michele Faucci\} and Kockum, \{Anton Frisk\} and Jonas Bylander and Giovanna Tancredi",

year = "2026",

month = dec,

doi = "10.1038/s41534-026-01356-2",

language = "English",

volume = "12",

journal = "NPJ Quantum Information",

issn = "2056-6387",

publisher = "Springer Nature",

}

Chen, L, Fors, SP, Yan, Z, Ali, A, Abad, T, Huang, T, Osman, A, Moschandreou, E, Lienhard, B, Kosen, S, Li, HX, Shiri, D, Liu, T, Hill, S, Amin, AA, Rehammar, R, Dahiya, M, Nylander, A, Rommel, M, Roudsari, AF, Caputo, M, Grönberg, L, Govenius, J, Dobsicek, M, Giannelli, MF, Kockum, AF, Bylander, J & Tancredi, G 2026, 'Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits', NPJ Quantum Information, vol. 12, 135. https://doi.org/10.1038/s41534-026-01356-2

TY - JOUR

T1 - Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits

AU - Chen, Liangyu

AU - Fors, Simon Pettersson

AU - Yan, Zixian

AU - Ali, Anaida

AU - Abad, Tahereh

AU - Huang, Tangyou

AU - Osman, Amr

AU - Moschandreou, Eleftherios

AU - Lienhard, Benjamin

AU - Kosen, Sandoko

AU - Li, Hang Xi

AU - Shiri, Daryoush

AU - Liu, Tong

AU - Hill, Stefan

AU - Amin, Abdullah Al

AU - Rehammar, Robert

AU - Dahiya, Mamta

AU - Nylander, Andreas

AU - Rommel, Marcus

AU - Roudsari, Anita Fadavi

AU - Caputo, Marco

AU - Grönberg, Leif

AU - Govenius, Joonas

AU - Dobsicek, Miroslav

AU - Giannelli, Michele Faucci

AU - Kockum, Anton Frisk

AU - Bylander, Jonas

AU - Tancredi, Giovanna

PY - 2026/12

Y1 - 2026/12

N2 - 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.

AB - 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.

UR - https://www.scopus.com/pages/publications/105047323908

U2 - 10.1038/s41534-026-01356-2

DO - 10.1038/s41534-026-01356-2

M3 - Article

AN - SCOPUS:105047323908

SN - 2056-6387

VL - 12

JO - NPJ Quantum Information

JF - NPJ Quantum Information

M1 - 135

ER -

Fast, unconditional reset and leakage reduction in fixed-frequency transmon qubits

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