A Compact Broadband Purcell Filter for Superconducting Quantum Circuits in a 3D Flip-Chip Architecture

Researchers have developed a compact broadband Purcell filter for superconducting quantum circuits, addressing a long-standing trade-off between qubit readout fidelity and decay rates. The filter, implemented on a 3D flip-chip platform, features a four-pole design that provides a flat 1 GHz passband centered at 7.68 GHz, achieving an attenuation of more than 45 dB¹. This innovation enables strong coupling between the readout resonator and the feedline while minimizing qubit decay through the Purcell effect. By overcoming this limitation, the filter paves the way for faster and more accurate qubit readout in quantum computing applications. The use of a 3D flip-chip architecture allows for increased design flexibility and compactness, making it an attractive solution for integrating Purcell filters in quantum circuits. This breakthrough matters because it has the potential to significantly improve the performance and reliability of quantum computing systems, enabling practitioners to develop more complex and powerful quantum applications.