Efficient computation of relaxation rates, mode hybridization, and surface losses in nonlinear superconducting quantum systems using DEC-QED*

DEC-QED is a recently developed computational method based on coarse-grained and hybridized field+charge degrees of freedom for simulating three-dimensional superconducting quantum devices [1]. We build on this method to develop an electrohydrodynamical spectral theory for the superconducting condensate field and its electromagnetic environment. This theory can efficiently and reliably quantify important performance metrics of superconducting quantum processors, such as relaxation rates, mode hybridization, and surface dielectric losses. To accurately account for radiative losses, we introduce a transparent boundary technique that correctly captures leakage from the finite system. The entire electrohydrodynamical problem is adapted to the DEC-QED formulation, making it suitable for the design and optimization of multiscale superconducting devices [2]. We demonstrate the approach by applying it to realistic superconducting device geometries.

[1] D. N. Pham, W. Fan, M. G. Scheer, and H. E. Tureci, Phys. Rev. A 107, 053704 (2023)

[2] D. N. Pham, R. D. Li, and H. E. Tureci, arXiv:2309.03435