Simulation of magnetic field and current density profile for flux-tunable superconducting qubit devices

We adopt a finite-element method [1] to solve the Maxwell-London equations to simulate magnetic field and current distributions in superconducting qubit devices. Taking into account both externally applied magnetic fields and supercurrents allows us to compute the total magnetic flux through any circuit loop. This is relevant, in particular, for flux-tunable qubits where the field generated by a flux-bias line current or external electromagnet tunes the qubit frequency. Our simulation may help inform the layout design for flux-tunable qubit devices, and mitigate flux crosstalk in large-scale superconducting circuits [2].

[1] Via et al. J. Appl. Phys., 113, 093905 (2013)

[2] Dai et al. PRX Quantum, 2, 040313 (2021)