DEC-QED: A flux-based 3D electrodynamic modeling approach to superconducting circuits and materials

  1. Dzung N. Pham,
  2. Wentao Fan,
  3. Michael G. Scheer,
  4. and Hakan E. Tureci
Modeling the behavior of superconducting electronic circuits containing Josephson junctions is crucial for the design of superconducting information processors and devices. In this
paper, we introduce DEC-QED, a computational approach for modeling the electrodynamics of superconducting electronic circuits containing Josephson junctions in arbitrary three-dimensional electromagnetic environments. DEC-QED captures the non-linear response and induced currents of BCS superconductors and accurately captures phenomena such as the Meissner effect, flux quantization and Josephson effects. Using a finite-element construction based on Discrete Exterior Calculus (DEC), DEC-QED can accurately simulate transient and long-time dynamics in superconductors. The expression of the entire electrodynamic problem in terms of the gauge-invariant flux field and charges makes the resulting classical field theory suitable for second quantization.

Computational modeling of decay and hybridization in superconducting circuits

  1. Michael G. Scheer,
  2. and Maxwell B. Block
We present a circuit theoretic technique for computing the complex frequencies and eigenmodes of superconducting circuits with radiative loss. We show that the transmon loss rates obtained
by our method agree with the established approximation C/Re[Y] away from resonance and do not diverge near resonance. Additionally, we demonstrate that a system of two resonators coupled to a common Purcell filter exhibits a pattern of hybridization that cannot be explained by a hierarchy of couplings and detunings. This is due to the significant influence of radiative loss on the mode couplings. As a result, it is necessary to include radiative boundary conditions even in simulations of coherent dynamics. Our simulation technique is useful for designing complex circuit quantum electrodynamic systems.