Superconducting Quantum Devices
– Superconducting qubits
Circuit design, diagnostic and calibration of single qubit and multi-qubit transmon devices for the implementation of hybrid classical/quantum and quantum algorithms. Experimental techniques for benchmarking coherence, control and readout fidelities (Rabi oscillations, Ramsey fringes, gate optimization techniques…) in the NISQ (Noisy Intermediate Scale Quantum) era. Two state of the art cryogenic and electronic setups to measure up to 25 and 40 superconducting qubits simultaneously.
References:
H. G. Ahmad, C. Jordan, R. van den B., D. Waardenburg, C. Zachariadis, P. Mastrovito, A. L. Georgiev, D. Montemurro, G. P. Pepe, M. Arthers, A. Bruno, F. Tafuri, O. Mukhanov, M. Arzeo, and D. Massarotti, Investigating the Individual Performances of Coupled Superconducting Transmon Qubits. Condensed Matter. 2023; 8(1):29.
H. G. Ahmad, R. Schiattarella, P. Mastrovito, A. Chiatto, A. Levochkina, M. Esposito, D. Montemurro, G. P. Pepe, A. Bruno, F. Tafuri, A. Vitiello, G. Acampora, D. Massarotti, Mitigating Errors on Superconducting Quantum Processors through Fuzzy Clustering, Adv Quantum Technol. 2024, 7, 2300400.
https://doi.org/10.1002/qute.202300400
– SFQ digital control and readout of superconducting qubits
Design, simulation and characterization of control and readout devices of superconducting qubits, based on single flux quantum (SFQ) digital logic. Integration of a quantum device with classical superconducting electronic chips.
References:
L. Di Palma, A. Miano, P. Mastrovito, D. Massarotti, M. Arzeo, G.P. Pepe, F. Tafuri, and O. Mukhanov, Discriminating the Phase of a Coherent Tone with a Flux-Switchable Superconducting Circuit, Phys. Rev. Applied 19, 064025 (2023)
– Josephson metamaterials for quantum microwave photonics
This research line aims at investigating superconducting quantum circuits, specifically, Josephson parametric amplifiers for quantum technologies applications raining from the low-noise readout of weak microwave signals to the generation and control of quantum states of the electromagnetic radiation in the microwave spectral range.
References:
A. Levochkina, H. Ahmad, P. Mastrovito, I. Chatterjee, G. Serpico, L. Di Palma, R. Ferroiuolo, R. Satariano, P. Darvehi, A. Ranadive, G. Cappelli, G. Le Gal, L. Planat, D. Montemurro, D. Massarotti, F. Tafuri, N. Roch, G. P. Pepe and M. Esposito “Investigating pump harmonics generation in a SNAIL-based traveling wave parametric amplifier”, Supercond. Sci. Technol. 37 115021 (2024)
A. Y. Levochkina, H.G. Ahmad, P. Mastrovito, I. Chatterjee, D. Massarotti, D. Montemurro, F. Tafuri, G.P. Pepe, M. Esposito, “Numerical simulations of Josephson Traveling Wave Parametric Amplifiers (JTWPAs): comparative study of open-source tools”, IEEE TAS, 34 3 (2024)
M. Esposito, A. Ranadive, L. Planat, S. Leger, D. Fraudet, V. Jouanny, O. Buisson, W. Guichard, C. Naud, J. Aumentado, F. Lecocq, N. Roch, “Observation of two-mode squeezing in a traveling wave parametric amplifier”, Physical Review Letter 128, 153603 (2022).
– Macroscopic Quantum Phenomena and Hybrid Quantum Devices
Realization and characterization of hybrid Josephson junctions and nanodevices, with barriers composed by different materials (ferromagnetic layers, semiconducting materials and nanowires, topological insulators), and HTc superconductors. Transport properties, electrodynamics in DC and microwave environment, proximity effect in unconventional regimes. Macroscopic quantum tunneling and energy level quantization in unconventional Josephson junctions.
References:
H. G. Ahmad, R. Satariano, R. Ferraiuolo, A. Vettoliere, C. Granata, D. Montemurro, G. Ausanio, L. Parlato, G. P. Pepe, F. Tafuri, D. Massarotti; Phase dynamics of tunnel Al-based ferromagnetic Josephson junctions. Appl. Phys. Lett. 3 June 2024; 124 (23): 232601.
https://doi.org/10.1063/5.0211006
H. G. Ahmad, M. Minutillo, R. Capecelatro, A. Pal, R. Caruso, G. Passarelli, M. G. Blamire, F. Tafuri, P. Lucignano and D. Massarotti, Coexistence and tuning of spin-singlet and triplet transport in spin-filter Josephson junctions. Commun Phys 5, 2 (2022).
https://doi.org/10.1038/s42005-021-00783-1
R. Caruso, D. Massarotti, G. Campagnano, A. Pal, H. G. Ahmad, P. Lucignano, M. Eschrig, M. G. Blamire, and F. Tafuri, Tuning of Magnetic Activity in Spin-Filter Josephson Junctions Towards Spin-Triplet Transport, Phys. Rev. Lett. 122, 047002 (2019),
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.047002
D. Massarotti, A. Pal, G. Rotoli, L. Longobardi, M. G. Blamire & F. Tafuri. Macroscopic quantum tunnelling in spin filter ferromagnetic Josephson junctions. Nat Commun 6, 7376 (2015).
https://doi.org/10.1038/ncomms8376
– Unconventional hybrid qubits and quantum devices for enhanced coherence and scalability
We propose alternative approaches to superconducting qubit technology, introducing qubit designs capable of eliminating the need for flux lines and/or enhance coherence. One innovation track will implement SIsFS junctions in a transmon geometry—ferrotransmons, or HTC Josephson junctions.
References:
R. Satariano, A. F. Volkov, H. G. Ahmad, L. Di Palma, R. Ferraiuolo, A. Vettoliere, C. Granata, D. Montemurro, L. Parlato, G.P. Pepe, F. Tafuri, G. Ausanio, D. Massarotti, Nanoscale spin ordering and spin screening effects in tunnel ferromagnetic Josephson junctions. Commun Mater 5, 67 (2024).
https://doi.org/10.1038/s43246-024-00497-1
A. Vettoliere, R. Satariano, R. Ferraiuolo, L. Di Palma, H. G. Ahmad, G. Ausanio, G. P. Pepe, F. Tafuri, D. Montemurro, C. Granata, L. Parlato, D. Massarotti; Aluminum-ferromagnetic Josephson tunnel junctions for high quality magnetic switching devices. Appl. Phys. Lett. 27 June 2022; 120 (26): 262601.
H. G. Ahmad, V. Brosco, A. Miano, L. Di Palma, M. Arzeo, D. Montemurro, P. Lucignano, G. P. Pepe, F. Tafuri, R. Fazio, and D. Massarotti, Hybrid ferromagnetic transmon qubit: Circuit design, feasibility, and detection protocols for magnetic fluctuations, Phys. Rev. B 105, 214522 (2022).
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.105.214522
V. Brosco, G. Serpico, V. Vinokur, N. Poccia, U. Vool, Superconducting Qubit Based on Twisted Cuprate Van der Waals Heterostructures, Phys. Rev. Lett. 132, 017003 (2024),
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.017003
– Superconducting nano/micro strip single photon detectors (SN(M)SPD)
State-of-the-art NbN superconducting nanostrip single photon detectors. Detection efficiency higher than 90% and dark count rate lower than 1 cps for profitability in quantum technology applications at the telecom wavelength 1550 nm. Design, fabrication and testing of superconducting microstrips based on MoSi and NbRe for single photon detection in the mid infrared domain.
References:
P. Ercolano, C. Cirillo, M. Ejrnaes, F. Chianese, D. Salvoni, C. Bruscino, R. Satariano, A. Cassinese, C. Attanasio, G.P. Pepe, L. Parlato, “Investigation of dark count rate in NbRe microstrips for single photon detection”, Superconductor Science and Technology vol. 36, art. n. 105011 (2023),
https://doi.org/10.1088/1361-6668/acf24a
M. Ejrnaes, C. Cirillo, D. Salvoni, F. Chianese, C. Bruscino, P. Ercolano, A. Cassinese, C. Attanasio, G. P. Pepe, L. Parlato, “Single photon detection in NbRe superconducting microstrips”, Applied Physics Letters vol. 121, art. n. 262601 (2022).
https://doi.org/10.1063/5.0131336
D. Salvoni, M. Ejrnaes, A. Gaggero, F. Mattioli, F. Martini, H. G. Ahmad, L. Di Palma, R. Satariano, X. Y. Yang, L. You, F. Tafuri, G. P. Pepe, D. Massarotti, D. Montemurro, L. Parlato, “Activation Energies in MoSi/Al Superconducting Nanowire Single-Photon Detectors”, Physical Review Applied vol. 18, art. n. 014006 (2022).
https://doi.org/10.1103/PhysRevApplied.18.014006
– Superconducting photon number resolving detectors
Array of superconducting nanostrips for photon number resolution. Light sources characterization reconstructing the photon number distribution with near unit fidelity. Unbiased generation of random numbers with photon number resolving detector employing the quantum properties of light.
References:
P. Ercolano, D. Salvoni, C. Bruscino, M. Di Giancamillo, C. Zhang, M. Ejrnaes, J. Huang, H. Li, L. You, L. Parlato, M. Martinelli, G. P. Pepe, “Superconducting PNR detector for photon sources characterization”, IEEE Transactions on Applied Superconductivity vol. 34, art. n. 2200105 (2024).
https://doi.org/10.1109/TASC.2024.3353709
P. Ercolano, C. Bruscino, D. Salvoni, C. Zhang, M. Ejrnaes, J. Huang, H. Li, L. You, L. Parlato, G. P. Pepe, “Time binning method for non-pulsed sources characterization with a superconducting photon number resolving detector”, IEEE Transactions on Quantum Engineering vol. 4, art. n. 4100609 (2023).
https://doi.org/10.1109/TQE.2023.3316797
– Quantum Metropolitan QKD Network
The network connects the Italian Quantum Backbone (IQB) node at the CNR Pozzuoli with the Meditech Competence Center, Campus S. Giovanni of the University of Naples, and the Department of Physics E. Panicni of the University of Naples Federico II, Monte S. Angelo. First permanent quantum communication infrastructure, entirely made with Italian technology, for the experimentation of new protocols to be used in telecommunications in an intrinsically inviolable way based on the principles of Quantum Mechanics. The connection between Naples and Matera QMANs, which terminates within the Centro di Geodesia Spaziale of the Italian Space Agency (ASI), is currently in progress: it will allow the integration between the terrestrial and the space segments proper of quantum communication.
The initiative, supported and coordinated by the Ministry of Industry and Made in Italy (MiMiT), has the following partners: Università degli Studi di Napoli Federico II, CNR-INO, INRiM, Leonardo, QTI srl, TIM, Telsy, ThinkQuantum, Cisco and Exprivia.
Superconducting strip photon detectors are used to enhance the performances of QKD protocols.
References:
G. Guarda, D. Ribezzo, D. Salvoni, C. Bruscino, P. Ercolano, M. Ejrnaes, L. Parlato, C. Zhang, H. Li, L. You, I. Vagniluca, C. De Lazzari, T. Occhipinti, G. P. Pepe, A. Zavatta, D. Bacco, “Decoy-state quantum key distribution over long-distance optical fiber”, Proceedings in SPIE Photonics West 2024, Quantum Computing, Communication, and Simulation 2024 vol. 12911, art. n. 129110D (2024).
https://doi.org/10.1117/12.3003698
C. Bruscino, P. Ercolano, D. Salvoni, M. Di Giancamillo, C. Zhang, M. Ejrnaes, H. Li, L. You, L. Parlato, M. Martinelli, G. P. Pepe, “High performance Superconducting Nanowire Single Photon Detectors for QKD applications”, IEEE Transactions on Applied Superconductivity vol. 34, art. n. 2200205 (2024).
https://doi.org/10.1109/TASC.2024.3355878
G. Guarda, D. Ribezzo, D. Salvoni, C. Bruscino, P. Ercolano, M. Ejrnaes, L. Parlato, C. Zhang, H. Li, L. You, I. Vagniluca, C. De Lazzari, T. Occhipinti, G. P. Pepe, A. Zavatta, D. Bacco, “BB84 decoy-state QKD protocol over long-distance optical fiber”, Proceedings in ICTON 2023, 23rd International Conference on Transparent Optical Networks, IEEE, p. 1-4 (2023).
https://doi.org/10.1109/ICTON59386.2023.10207397