# Generation, dynamical buildup and detection of bi- and mulipartite entangled states in cavity systems

## TL;DR

This paper explores methods to generate, enhance, and detect bipartite and multipartite entangled states in cavity quantum systems, including microcavities and driven emitter-cavity setups, highlighting new protocols and their robustness.

## Contribution

It introduces novel schemes for entanglement generation in cavity systems, optimizing correlations, phase matching, and dynamical buildup, advancing quantum optical entanglement control.

## Key findings

- Strong bipartite entanglement between polariton branches achieved.
- Multipartite entanglement among cavity modes demonstrated.
- Entanglement production is most effective during initial laser oscillations.

## Abstract

We inspect different quantum optical setups from the viewpoint of entanglement generation and detection. As a first step we consider a planar semiconductor microcavity and optimize the Bell-type correlations and their robustness against dephasing to create strong bipartite entanglement between polariton branches, which subsequently can be transfered to the emitted photons. In a second step, in order to create multipartite entangled light, we place the microcavity in an optical resonator driven by pump pulses with a frequency comb spectrum. For this system we show how phase matching of all comb modes can be achieved and will lead to indistinguishable scattering processes causing entanglement among every mode. Finally we demonstrate the buildup of entanglement in the dissipative dynamics of emitters coupled to a single cavity photon mode driven by an external laser. From a Floquet master equation approach we find that entanglement production predominates during the first few laser oscillation periods.