Decoherence Estimation of Superconducting Qubit

Decoherence of quantum bits arises primarily from the parasitic resistance within the qubit. This study presents the analysis of the decoherence process due to physical interactions between the qubit photons and parasitic resistance atoms, utilizing exclusively the Caldeira-Leggett electrical model, without relying on external Hamiltonians. The analysis shows a good agreement between the model of the electrical noise and the Johnson-Nyquist noise. The emission and absorption rates of the qubit's coherent loss, required for the Lindblad master equation that approximates the decoherence, are obtained. A numerical substitution in the analysis result yields a strong correlation with previous measurements. The present analysis enables also the derivation of the appropriate circuit characteristics for future simulations.