Experimental observation of dynamical blockade between transmon qubits via ZZ interaction engineering

• URL: http://arxiv.org/abs/2601.11714v1
• Date: Fri, 16 Jan 2026 19:02:00 GMT
• Title: Experimental observation of dynamical blockade between transmon qubits via ZZ interaction engineering
• Authors: Marco Riccardi, Aviv Glezer Moshe, Guido Menichetti, Riccardo Aiudi, Carlo Cosenza, Ashkan Abedi, Roberto Menta, Halima Giovanna Ahmad, Diego Nieri Orfatti, Francesco Cioni, Davide Massarotti, Francesco Tafuri, Vittorio Giovannetti, Marco Polini, Francesco Caravelli, Daniel Szombati,
• Abstract summary: We report the experimental realization of strong longitudinal (ZZ) coupling between two superconducting transmon qubits achieved solely through capacitive engineering.<n>We measure cross-Kerr inter-qubit interaction strengths ranging from 10 MHz up to 350 MHz, more than an order of magnitude larger than previously observed in similar capacitively coupled systems.
• Score: 0.4551401337908835
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We report the experimental realization of strong longitudinal (ZZ) coupling between two superconducting transmon qubits achieved solely through capacitive engineering. By systematically varying the qubit frequency detuning, we measure cross-Kerr inter-qubit interaction strengths ranging from 10 MHz up to 350 MHz, more than an order of magnitude larger than previously observed in similar capacitively coupled systems. In this configuration, the qubits enter a strong-interaction regime in which the excitation of one qubit inhibits that of its neighbor, demonstrating a dynamical blockade mediated entirely by the engineered ZZ coupling. Circuit quantization simulations accurately reproduce the experimental results, while perturbative models confirm the theoretical origin of the energy shift as a hybridization between the computational states and higher-excitation manifolds. We establish a robust and scalable method to access interaction-dominated physics in superconducting circuits, providing a pathway towards solid-state implementations of globally controlled quantum architectures and cooperative many-body dynamics.

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