“…The analytical methods used in this paper are effective tools to analyze the longterm stability of the quantum system parameters, such as decoherence times of quantum dots [46], optical gains of laser diodes using quantum wires [47,48], and spontaneous currents in superconducting rings [49,50], and are not limited to the superconducting qubit system discussed here. The presence of fluctuations in T 1 , T R 2 and qubit frequency highlights the importance of recalibrating qubits frequently, as these fluctuations contribute to errors in quantum gate fidelities and quantum teleportation fidelities [51,52], and this study provides an approach for selecting the ideal working points of tunable superconducting Xmon qubits to avoid the unstable area. Basically, this emphasizes that in order to accurately evaluate the quality of a qubit, not only the exceptional coherence time, but also the long-term average value should be estimated.…”