Programmable Microwave Cluster States via Josephson Metamaterials

ORAL

Abstract

Cluster states are a key resource for continuous-variable quantum computing, enabling measurement-based protocols that can scale beyond qubit-based architectures. Here, we demonstrate the on-demand generation of multimode entangled microwave cluster states using a programmable Josephson Traveling-Wave Parametric Amplifier (JTWPA) operated in the three-wave mixing regime. By injecting a tailored set of pump tones with an arbitrary waveform generator, we engineer frequency-specific nonlinear couplings between multiple modes, allowing different graph topologies. Entanglement is verified via frequency-resolved heterodyne detection of quadrature nullifiers, confirming the target graph structures. Our scheme is reconfigurable via the pump spectrum and supports scalability by exploiting the wide bandwidth and spatial homogeneity of the JTWPA. This platform enables scalable measurement-based quantum information processing in the microwave domain, fully compatible with superconducting circuits.

*We would like to thank the team at VTT Technical Research Centre of Finland Ltd for providing the JTWPA: Debopam Datta, Wisa Förbom, Joonas Govenius, Robab Najafi Jabdaraghi, Janne Lehtinen, Jaani Nissilä, Mika Prunnila, Jorden Senior, Nils Tiencken, and Visa Vesterinen. This work is partially supported by the European project MiSS. MiSS is funded by the European Union through the Horizon Europe 2021-2027 Framework Programme, Grant agreement ID: 101135868. This work is partially supported by the European project MetSuperQ. The 23FUN08 MetSuperQ project has received funding from the European Partnership on Metrology, co-financed from the European Union's Horizon Europe Research and Innovation Programme and by the Participating States. This work is partially supported by the Italian project CalQuStates. The PRIN 2022 CalQuStates project received funding by the European Union – Next Generation EU Mission 4 Component 1 CUP E53D23002210006

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Publication: Alocco et al., "Programmable Microwave Cluster States via Josephson Metamaterials", 2025,
2507.22823, arXiv, https://arxiv.org/abs/2507.22823

Presenters

  • Alessandro Alocco

    • Department of Applied Science and Technology, Polytechnic University of Turin
    • Polytechnic University of Turin - INRiM

Authors

  • Alessandro Alocco

    • Department of Applied Science and Technology, Polytechnic University of Turin
    • Polytechnic University of Turin - INRiM

  • Andrea Celotto

    • Department of Applied Science and Technology, Polytechnic University of Turin
    • Polytechnic University of Turin - INRiM

  • Emanuele Palumbo

    • Department of Applied Science and Technology, Polytechnic University of Turin

  • Bernardo Galvano

    • Department of Engineering, University of Palermo
    • University of Palermo - INRiM

  • Patrizia Livreri

    • Department of Engineering, University of Palermo
    • University of Palermo

  • Luca Fasolo

    • Quantum Metrology and Nanotechnology Division, Istituto Nazionale di Ricerca Metrologica
    • INRiM

  • Luca Callegaro

    • Quantum Metrology and Nanotechnology Division, Istituto Nazionale di Ricerca Metrologica
    • INRiM

  • Emanuele Enrico

    • Quantum Metrology and Nanotechnology Division, Istituto Nazionale di Ricerca Metrologica
    • INRiM