Measurement of quantum correlations in top-quark pair production with the CMS detector.

This work investigates quantum correlations in top-quark pair production using dileptonic final states collected by the CMS experiment at the LHC. The analysis treats the $t\bar{t}$ system as an effective two-qubit state, allowing studies of entanglement, steerability, and related quantum effects through its spin density matrix. Using the full Run 2 dataset at 13 TeV, the measurement refines previous CMS results and extends them to new regions of phase space. Sensitivity studies of the observables $D$ and $\tilde{D}$ probe entanglement both at the production threshold and the boosted regime, the latter studied for the first time in the dileptonic channel at CMS. Preliminary results utilizing novel probes of quantum correlation observables based are also presented and represent a sensitive novel way to measure quantum correlations in the $t\bar{t}$ system.