Modeling the effects of 1/f dephasing noise on a coherently driven qubit

Accurately describing the impact of highly non-Markovian 1/f dephasing noise on superconducting qubits via simple modelling tools is challenging even if the noise is treated as being classical.  Typical approaches are to either perform a brute-force numerical average over many noise realizations, or use ad-hoc time-local master equations whose validity is often not clear.  In this talk, we use a generalized cumulant expansion to rigorously derive an effective time-local Lindblad style master equation that describes the evolution of a driven qubit subject to classical 1/f dephasing noise.  We find that the effective dissipation in this master equation is explicitly time-dependent, and also has a form that depends both on the driving as well as the noise spectral density.  Our analysis reveals that over a large set of experimentally relevant parameters, our effective description leads to evolution that can be substantially more accurate than other more commonly used approximation techniques.