Exploring Energy Dissipation Mechanisms in Chaotic Floquet States of Driven Superconducting Qubits.

Chaos rising in driven superconducting circuits (SQCs) is highlighted recently as the origin of drive-induced adversities in quantum applications and has been the long-lasting theme in nonlinear physics. Despite such importances, experimental studies on chaotic dynamics of SQCs are in their infancy. Particularly for transmons, essential building block for superconducting quantum computers, experimental traces on their chaotic dynamics under strong drives have remained elusive except that several features relevant with chaos are lately elucidated. Here, we discover significant nonlinear dissipation of the resonator photons, whereby extracting enormously large energy dissipation (ED) rates from the transmons to baths. We explore energy dissipation (ED) mechanism from chaotic Floquat states of transmons through the bare frequency response of the dispersively coupled resonators, which appears when the transmon ground state falls into the chaotic layer. Our calculation based on Floquet-Markov formalism indicates that the observed ED rates far exceed the upper bound of Ohmic radiative loss mechanism but can be quantified based on combinations between dielectric and quasiparticle loss models. These findings reveal the dissipation-related properties of chaotic Floquet states in driven SQCs. This work deepens our fundamental understanding of driven nonlinear systems and may help us overcome challenges in superconducting quantum technologies originating from chaos.