Improving readout of a superconducting qubit using the path signature method*

One major challenge in quantum computing is to implement fast, high-accuracy quantum state readout. For superconducting circuits, this problem reduces to a time series classification problem [1]. We propose that using path signature methods to extract features can enhance existing techniques for quantum state discrimination [2]. We demonstrate the superior performance of our proposed approach over conventional methods in distinguishing three different quantum states on real experimental data from a superconducting transmon qubit.

[1] J Heinsoo, C Andersen, A Remm, S Krinner, T Walter, Y Salathé, S Gasparinetti, J Besse, A Potočnik, A Wallraff, C Eichler. Phys. Rev. Applied 10, 034040 

[2] J Morrill, A Fermanian, P Kidger, T Lyons. arXiv preprint arXiv:2006.00873, 2020