Exceeding the Parametric Drive Strength Threshold in Nonlinear Circuits
Abstract
Superconducting quantum circuits rely on strong drives to implement fast gates, high-fidelity readout, and state stabilization. However, these drives can induce uncontrolled excitations, so-called "ionization", that compromise the fidelity of these operations. While now well-characterized in the context of qubit readout, it remains unclear how general this limitation is across the more general setting of parametric control. Here, we demonstrate that a nonlinear coupler, exemplified by a transmon, undergoes ionization under strong parametric driving, leading to a breakdown of coherent control and thereby limiting the accessible gate speeds. Through experiments and numerical simulations, we associate this behavior with the emergence of drive-induced chaotic dynamics, which we characterize quantitatively using the instantaneous Floquet spectrum. Our results reveal that the Floquet spectrum provides a unifying framework for understanding strong-drive limitations across a wide range of operations on superconducting quantum circuits. This insight establishes fundamental constraints on parametric control and offers design principles for mitigating drive-induced decoherence in next-generation quantum processors.
Cite
@article{arxiv.2506.03456,
title = {Exceeding the Parametric Drive Strength Threshold in Nonlinear Circuits},
author = {Mingkang Xia and Cristóbal Lledó and Matthew Capocci and Jacob Repicky and Benjamin D'Anjou and Ian Mondragon-Shem and Ryan Kaufman and Jens Koch and Alexandre Blais and Michael Hatridge},
journal= {arXiv preprint arXiv:2506.03456},
year = {2025}
}