# Quantum Rabi oscillations in coherent and in mesoscopic Schr\"odinger "cat" field states

## TL;DR

This paper investigates Rabi oscillations in mesoscopic quantum states, demonstrating the creation of Schrödinger cat states with high photon numbers and analyzing their quantum coherence and decoherence dynamics.

## Contribution

It reports the first experimental realization of mesoscopic Schrödinger cat states with tens of photons using Rydberg atoms and superconducting cavities, advancing quantum state control.

## Key findings

- Successful generation of cat states with ~ tens of photons
- Observation of quantum coherence and decoherence in these states
- Measurement of Wigner functions revealing quantum superpositions

## Abstract

The simple resonant Rabi oscillation of a two-level system in a single-mode coherent field reveals complex features at the mesoscopic scale, with oscillation collapses and revivals. Using slow circular Rydberg atoms interacting with a superconducting microwave cavity, we explore this phenomenon in an unprecedented range of interaction times and photon numbers. We demonstrate the efficient production of `cat' states, quantum superposition of coherent components with nearly opposite phases and sizes in the range of few tens of photons. We measure cuts of their Wigner functions revealing their quantum coherence and observe their fast decoherence. This experiment opens promising perspectives for the rapid generation and manipulation of non-classical states in cavity and circuit Quantum Electrodynamics.