On-demand transposition across light-matter interaction regimes in bosonic cQED

TL;DR

This paper demonstrates rapid, on-demand switching between different light-matter interaction regimes in bosonic cQED systems, enabling versatile quantum information processing without compromising cavity coherence.

Contribution

It introduces the first experimental implementation of fast interaction regime switching in bosonic cQED using flux-tunable transmons, enhancing quantum control capabilities.

Findings

Achieved nanosecond-scale frequency tunability of transmon-cavity system.

Enabled fast creation of cavity Fock states through resonant interactions.

Suppressed unwanted dynamics during idle periods.

Abstract

The diverse applications of light-matter interactions in science and technology stem from the qualitatively distinct ways these interactions manifest, prompting the development of physical platforms that can interchange between regimes on demand. Bosonic cQED employs the light field of high-Q superconducting cavities coupled to non-linear circuit elements, harnessing the rich dynamics of their interaction for quantum information processing. However, implementing fast switching of the interaction regime without deteriorating the cavity coherence is a significant challenge. We present the first experiment to achieve this feat, combining nanosecond-scale frequency tunability of a transmon coupled to a cavity with lifetime of hundreds of microseconds. Our implementation affords a range of new capabilities for quantum information processing; from fast creation of cavity Fock states using resonant interaction and interchanging tomography techniques at qualitatively distinct interaction regimes on the fly, to the suppression of unwanted cavity-transmon dynamics during idle evolution. By bringing flux tunability into the bosonic cQED toolkit, our work opens up a new paradigm to probe the full range of light-matter interaction dynamics within a single platform and provides valuable new pathways towards robust and versatile quantum information processing.