Dr. Halima Giovanna Ahmad

The first public 24-qubit superconducting quantum computing platform in Italy: a roadmap towards quantum utility

The roadmap towards quantum utility requires hardware platforms with a sufficient number of qubits, single- and two-qubit gate fidelities, and low readout errors. Among the most promising hardware, superconducting quantum platforms have earned considerable attention [1,2]. Their artificial nature favors the engineering of coherence [3], novel control and readout [4-5], and tunability [4,6-7], as well as coupling schemes for enhanced scalability [8,9]. In the frame of the Spoke 10 of the National Center for High-Performance Computing, Big Data and Quantum Computing Center (ICSC), we here report on preliminary results on the performances of a modular and scalable infrastructure up to a 24-transmon qubits Quantum Processing Unit (QPU). We will discuss the fundamental role played by calibration and gate pulses optimization procedures [10], as well as the impact of decoherence and noise, in the Noisy and Intermediate Scale Quantum (NISQ) era [11]. Within the final goal to provide a functional scalable infrastructure with up to 40 transmon qubits by the end of 2024, we here also report on the experimental validation of a novel Quantum Error Mitigation (QEM) algorithm on a 5-qubit superconducting QPU, which uses Fuzzy C-Means (FCM) clustering to identify and mitigate measurement error patterns in NISQ devices [11]. Such a technique may provide fundamental improvements on the output readout of quantum algorithms on devices with a larger number of qubits, thus allowing the field to implement more complex quantum algorithms. [1] Arute, F., et al., Nature 574, 505–510 (2019) [2] Kim, Y., et al., Nature 618, 500–505 (2023) [3] Siddiqi, I., Nat. Rev. Mater. 6, 875–891 (2021) [4] P. Krantz, et al., Appl. Phys. Rev. 1 June 2019; 6 (2): 021318 [5] L. Di Palma, Phys. Rev. Applied 19, 064025 (2023) [6] Casparis, L., et al., Nature Nanotech. 13, 915–919 (2018) [7] Ahmad H.G., et al., Phys. Rev. B 105, 214522 (2022) [8] Majer, J., et al., Nature 449, 443–447 (2007) [9] Yan F. et al, Phys. Rev. Applied 10, 054062 (2018) [10] Ahmad H.G., et al., Condensed Matter. 2023; 8(1):29. [11] Ahmad H.G., et al., Adv Quantum Technol. 2024, 2300400.