Real-time adaptive tracking of fluctuating relaxation rates in superconducting qubits

Fuente: arXiv
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Main Authors: Berritta, Fabrizio, Benestad, Jacob, Krzywda, Jan A., Krause, Oswin, Marciniak, Malthe A., Krøjer, Svend, Warren, Christopher W., Hogedal, Emil, Nylander, Andreas, Ahmad, Irshad, Osman, Amr, Biznárová, Janka, Rommel, Marcus, Roudsari, Anita Fadavi, Bylander, Jonas, Tancredi, Giovanna, Danon, Jeroen, Hastrup, Jacob, Kuemmeth, Ferdinand, Kjaergaard, Morten
Format: Preprint
Published: 2025
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author Berritta, Fabrizio
Benestad, Jacob
Krzywda, Jan A.
Krause, Oswin
Marciniak, Malthe A.
Krøjer, Svend
Warren, Christopher W.
Hogedal, Emil
Nylander, Andreas
Ahmad, Irshad
Osman, Amr
Biznárová, Janka
Rommel, Marcus
Roudsari, Anita Fadavi
Bylander, Jonas
Tancredi, Giovanna
Danon, Jeroen
Hastrup, Jacob
Kuemmeth, Ferdinand
Kjaergaard, Morten
author_facet Berritta, Fabrizio
Benestad, Jacob
Krzywda, Jan A.
Krause, Oswin
Marciniak, Malthe A.
Krøjer, Svend
Warren, Christopher W.
Hogedal, Emil
Nylander, Andreas
Ahmad, Irshad
Osman, Amr
Biznárová, Janka
Rommel, Marcus
Roudsari, Anita Fadavi
Bylander, Jonas
Tancredi, Giovanna
Danon, Jeroen
Hastrup, Jacob
Kuemmeth, Ferdinand
Kjaergaard, Morten
contents The fidelity of operations on a solid-state quantum processor is fundamentally bounded by environmental decoherence. Characterizing environmental fluctuations is challenging because the acquisition time of nonadaptive experimental protocols limits temporal precision and can average out rapid features of the underlying dynamics. Here, we overcome this temporal-resolution limit by two orders of magnitude using a field-programmable gate-array (FPGA) powered classical controller that adaptively and continuously tracks the relaxation-time fluctuations of two fixed-frequency superconducting transmon qubits, which exhibit average relaxation times of approximately 0.17 ms and occasionally exceed 0.5 ms. We report events in which the relaxation time switches by nearly an order of magnitude over timescales of just tens of milliseconds, rather than minutes or hours as previously reported. Our real-time Bayesian estimation protocol estimates relaxation times within a few milliseconds, close to the decoherence timescale itself. Our statistical analysis further suggests that some of these fast fluctuations arise from two-level systems switching at rates up to 10 Hz, four orders of magnitude faster than earlier reports. These results redefine the timescales relevant for calibration in superconducting quantum processing units, establish a reference for rapid relaxation-rate characterization in device screening, and improve our understanding of fast relaxation dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09576
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Real-time adaptive tracking of fluctuating relaxation rates in superconducting qubits
Berritta, Fabrizio
Benestad, Jacob
Krzywda, Jan A.
Krause, Oswin
Marciniak, Malthe A.
Krøjer, Svend
Warren, Christopher W.
Hogedal, Emil
Nylander, Andreas
Ahmad, Irshad
Osman, Amr
Biznárová, Janka
Rommel, Marcus
Roudsari, Anita Fadavi
Bylander, Jonas
Tancredi, Giovanna
Danon, Jeroen
Hastrup, Jacob
Kuemmeth, Ferdinand
Kjaergaard, Morten
Quantum Physics
Mesoscale and Nanoscale Physics
The fidelity of operations on a solid-state quantum processor is fundamentally bounded by environmental decoherence. Characterizing environmental fluctuations is challenging because the acquisition time of nonadaptive experimental protocols limits temporal precision and can average out rapid features of the underlying dynamics. Here, we overcome this temporal-resolution limit by two orders of magnitude using a field-programmable gate-array (FPGA) powered classical controller that adaptively and continuously tracks the relaxation-time fluctuations of two fixed-frequency superconducting transmon qubits, which exhibit average relaxation times of approximately 0.17 ms and occasionally exceed 0.5 ms. We report events in which the relaxation time switches by nearly an order of magnitude over timescales of just tens of milliseconds, rather than minutes or hours as previously reported. Our real-time Bayesian estimation protocol estimates relaxation times within a few milliseconds, close to the decoherence timescale itself. Our statistical analysis further suggests that some of these fast fluctuations arise from two-level systems switching at rates up to 10 Hz, four orders of magnitude faster than earlier reports. These results redefine the timescales relevant for calibration in superconducting quantum processing units, establish a reference for rapid relaxation-rate characterization in device screening, and improve our understanding of fast relaxation dynamics.
title Real-time adaptive tracking of fluctuating relaxation rates in superconducting qubits
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2506.09576