Cavity cat states in driven microwave cavities from the interaction of cavity modes to rotational states of molecules

Schrödinger cat states are important, yet hard-to-prepare resources in fields such as quantum information and sensing. We find that coupling rotational states of a polar molecule to a driven microwave cavity generates robust Schrödinger cat states. Above a critical driving threshold, enhanced photon populations push the molecule-cavity system into strong coupling, where the eigenstates are molecule-cavity cat states, as demonstrated by exact diagonalization and a Schrieffer-Wolff transformation. Our results suggest that internal molecular rotations are an alternative to fabricated nonlinearities for cavity quantum state engineering.