Ultrastrong coupling between light and matter has, in the past decade, transitioned from a
theoretical idea to an experimental reality. It is a new regime of quantum light–matter …

In quantum electrodynamics, the choice of gauge influences the form of light–matter
interactions. However, gauge invariance implies that all physical results should be …

The interaction between light and matter remains a central topic in modern physics despite
decades of intensive research. Coupling an isolated emitter to a single mode of the …

Recent technological developments have made it increasingly easy to access the non-
perturbative regimes of cavity quantum electrodynamics known as ultrastrong or deep strong …

Vacuum fluctuations fundamentally affect an atom by inducing a finite excited state lifetime
along with a Lamb shift of its transition frequency. Here we report the reverse effect …

Microwave optomechanical circuits have been demonstrated to be powerful tools for both
exploring fundamental physics of macroscopic mechanical oscillators, as well as being …

We report experimental and theoretical results on the extremely large Lamb shift in a
multimode circuit quantum electrodynamics (QED) system in the deep-strong coupling …

Light-matter interaction, and the understanding of the fundamental physics behind, is the
scenario of emerging quantum technologies. Solid state devices allow the exploration of …

The progression of materials science has led us down a path of rich discovery in the realm of
nanophotonics. Recent strides in metamaterials and plasmonics research have allowed for …