Generation and Read-Out of Many-Body Bell Correlations with a Probe Qubit

As demand for quantum technologies increases, so does the need to generate and classify nonclassical correlations in complex many-body systems. We introduce a simple and versatile method for creating and certifying entanglement and many-body Bell correlations. This method relies on a single qubit interacting with an N-qubit system. We demonstrate that (i) such pairwise interaction is sufficient to induce many-body quantum correlations, and (ii) the qubit can serve as a probe to extract all information about these correlations. Thus, single-qubit measurements reveal multipartite entanglement and N-body Bell correlations, enabling the rapid and efficient certification of nonclassicality in complex systems.