Broken selection rule in the quantum Rabi model

Understand

Understanding the interaction between light and matter is very relevant for fundamental studies of quantum electrodynamics and for the development of quantum technologies.

• The quantum Rabi model captures the physics of a single atom interacting with a single photon at all regimes of coupling strength.
• We report the spectroscopic observation of a resonant transition that breaks a selection rule in the quantum Rabi model, implemented using an $LC$ resonator and an artificial atom, a superconducting qubit.
• The eigenstates of the system consist of a superposition of bare qubit-resonator states with a relative sign.