Resolving non-perturbative renormalization of a microwave-dressed weakly anharmonic superconducting qubit

TL;DR

This paper develops a non-perturbative, non-Floquet theoretical framework to accurately describe microwave-dressed superconducting qubits in strong driving regimes, surpassing traditional perturbation approaches.

Contribution

It introduces a novel theoretical method that captures the dynamics of strongly driven transmon-resonator systems beyond existing approximations.

Findings

Interaction and mode properties are significantly renormalized under strong driving.

The new theory matches experimental results with high accuracy.

It provides insights for fast quantum gate implementation and qubit engineering.

Abstract

Microwave driving is a ubiquitous technique for superconducting qubits (SCQs), but the dressed states description based on the conventionally used perturbation theory cannot fully capture the dynamics in the strong driving limit. Comprehensive studies beyond these approximations applicable to transmon-based circuit quantum electrodynamics (QED) systems are unfortunately rare as the relevant works have been mainly limited to single-mode or two-state systems. In this work, we investigate a microwave-dressed transmon coupled to a single quantized mode over a wide range of driving parameters. We reveal that the interaction between the transmon and resonator as well as the properties of each mode is significantly renormalized in the strong driving limit. Unlike previous theoretical works, we establish a non-recursive, and non-Floquet theory beyond the perturbative regimes, which excellently quantifies the experiments. This work expands our fundamental understanding of dressed cavity QED-like systems beyond the conventional approximations. Our work will also contribute to fast quantum gate implementation, qubit parameter engineering, and fundamental studies on driven nonlinear systems.