Systematic Characterization of Transmon Qubit Stability with Thermal Cycling

Abstract

The temporal stability and reproducibility of qubit parameters are critical for the long-term operation and maintenance of superconducting quantum processors. In this work, we present a comprehensive longitudinal characterization of 27 frequency-tunable transmon qubits spanning over one year across four thermal cycles. Our results establish a distinct hierarchy of stability for superconducting hardware. We find that the intrinsic device parameters determining the qubit frequency and the baseline energy relaxation times ($T_1$) exhibit high robustness against thermal stress, characterized by frequency deviations typically confined within 0.5\% and non-degraded coherence baselines. In stark contrast, the environmental variables, specifically the background magnetic flux offsets and the microscopic landscape of two-level system (TLS) defects, undergo a significant stochastic reconfiguration after each cycle. By employing frequency-dependent relaxation spectroscopy and a quantitative metric, the $T_1$ Spectral Topography Fidelity, we demonstrate that thermal cycling acts as a ``hard reset'' for the local defect environment. This process introduces a level of spectral randomization equivalent to thousands of hours of continuous low-temperature evolution. These findings confirm that while the fabrication quality is preserved, the specific noise realization is statistically distinct for each thermal cycle, necessitating automated recalibration strategies for large-scale quantum systems.

7 pages, 4 figures

References in corpus (27)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• A Quantum Engineer's Guide to Superconducting Qubits
• Superconducting Qubits: Current State of Play
• Strong quantum computational advantage using a superconducting quantum processor
• Suppressing quantum errors by scaling a surface code logical qubit
• New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds
• Towards understanding two-level-systems in amorphous solids -- Insights from quantum circuits
• Transmon qubit with relaxation time exceeding 0.5 milliseconds
• Surface participation and dielectric loss in superconducting qubits
• Fluctuations of Energy-Relaxation Times in Superconducting Qubits
• Decoherence benchmarking of superconducting qubits
• Materials loss measurements using superconducting microwave resonators
• Genuine 12-qubit entanglement on a superconducting quantum processor
• Microwave response of vortices in superconducting thin films of Re and Al
• Measuring the Capabilities of Quantum Computers
• Interacting two-level defects as sources of fluctuating high-frequency noise in superconducting circuits
• Lifetime and Coherence of Two-Level Defects in a Josephson Junction
• Generalized Tunneling Model for TLS in amorphous materials and its predictions for their dephasing and the noise in superconducting microresonators
• Two-level systems in superconducting quantum devices due to trapped quasiparticles
• Squeezed hole spin qubits in Ge quantum dots with ultrafast gates at low power
• Bulk and surface loss in superconducting transmon qubits
• TLS Dynamics in a Superconducting Qubit Due to Background Ionizing Radiation
• Quantum Sensors for Microscopic Tunneling Systems
• Mitigating Losses of Superconducting Qubits Strongly Coupled to Defect Modes
• Multiplexing Superconducting Qubit Circuit for Single Microwave Photon Generation
• Significance of an external magnetic field on two-phonon processes in gated lateral semiconductor quantum dots
• Telegraph flux noise induced beating Ramsey fringe in transmon qubits