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Flux-modulated tunable interaction regimes in two strongly nonlinear oscillators

J. D. Koenig1, G. Barbieri1, F. Fani Sani1, C. A. Potts1,2, M. Kounalakis1,3,*, and G. A. Steele1

  • *Contact author: marios.kounalakis@gmail.com
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Phys. Rev. Research 8, 013192 – Published 19 February, 2026

DOI: https://doi.org/10.1103/3pf2-8n9b

Abstract

The ability to efficiently simulate a variety of interacting quantum systems on a single device is an overarching goal for digital and analog quantum simulators. In circuit quantum electrodynamical systems, strongly nonlinear superconducting oscillators are typically realized using transmon qubits, featuring a wide range of tunable couplings that are mainly achieved via flux-dependent inductive elements. Such controllability is highly desirable both for digital quantum information processing and for analog quantum simulations of various physical phenomena, such as arbitrary spin-spin interactions. Furthermore, broad tunability facilitates the study of driven-dissipative oscillator dynamics in previously unexplored parameter regimes. In this work, we demonstrate the ability to selectively activate different dynamical regimes between two strongly nonlinear oscillators using parametric modulation. In particular, our scheme enables access to regimes that are dominated by photon hopping, two-mode squeezing, or cross-Kerr interactions. Finally, we observe level repulsion and attraction between Kerr-nonlinear oscillators in regimes where the nonlinearities exceed the coupling strengths and decay rates of the system. Our results could be used for realizing purely analog quantum simulators to study arbitrary spin systems as well as for exploring strongly nonlinear oscillator dynamics in previously unexplored interaction regimes.

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Phys. Rev. Research 8, 013192– Published 19 February, 2026
  • Received 10 November 2025
  • Accepted 19 January 2026
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