Electromagnetic Feature Extraction in Superconducting Quantum Circuits: An Open-Source Finite-Element Workflow Using Palace

TL;DR

This paper introduces an open-source finite element workflow using Palace for electromagnetic feature extraction in superconducting quantum circuits, achieving high accuracy and scalability for circuit design and analysis.

Contribution

The paper presents a novel, automated, open-source workflow for electromagnetic analysis of superconducting circuits using Palace, enabling accurate and scalable design processes.

Findings

Resonator frequency predictions within 0.3% of measurements

External couplings predicted within 16% of cryogenic data

Workflow matches commercial tools in accuracy with open-source advantages

Abstract

Accurate electromagnetic (EM) feature extraction, including element characterization, eigenmodes, and field distributions, is essential for superconducting quantum circuit design. To streamline this process, we present a workflow built around Palace, an open-source, high-performance finite element method solver tailored for quantum applications. Starting from circuit layouts, the workflow automates mesh generation, multiple EM solver processing, and EM-to-Hamiltonian post-processing. We benchmark the workflow on a chip with bare resonators and qubits coupled with readout resonators, achieving resonator frequencies prediction within 0.3% and 3 out of 4 external couplings within 16% of cryogenic measurements. These results demonstrate open-source EM tools can match commercial accuracy while offering scalable, license-free analysis. Our Palace-based workflow provides an accessible and extensible foundation for rapid superconducting circuit development and materials-loss studies.