Modeling Superconducting Microwave Systems with DEC-QED: Performance and Applications*

DEC-QED is a gauge-invariant flux-based modeling approach to Josephson-junctions-based elements embedded in three-dimensional electromagnetic environments of arbitrary complexity. The system of Maxwell's equations coupled to nonlinear order parameter equations of the electronic condensate field of a superconductor is solved by defining coarse-grained flux fields living on the discrete edges of the tetrahedral discretization of the domain. This approach naturally captures the nonlinear response of induced supercurrents to applied fields, enabling accurate modeling of the dynamics in superconducting microwave systems. We analyze the performance of DEC-QED as a complete computational toolbox including a mesher on the modeling of currents and cross-talk in a test geometry. We also discuss the implementation of open boundary conditions for accurate computation of radiative contribution to T1 times of weakly anharmonic superconducting qubits.