Polarization and spin correlations play an important role in precision physics and searches for Beyond Standard Model physics. Recently, there has been interest in using them to study quantum information phenomena, particularly quantum entanglement, at high energies. In this talk, I present some of these ideas, focusing on top quarks and weak vector bosons. In the first part, I will demonstrate that entanglement can be studied in the semileptonic channel of top quark pair production. Although inferring the hadronic top quark is challenging, this problem is overcome by using an optimal polarimeter, which relies on the kinematics of the top quark decay. I will also introduce a formalism that incorporates non-kinematical information available at the event level to enhance the sensitivity of the polarimeter to the hadronic top quark spin and show that the results can be improved by up to 40%. In the second part, I will provide a phenomenological study of next-to-leading-order effects on angular coefficients and quantum observables in diboson production. I will show that some of these effects can be large and, in some cases, disturb the properties of the density matrix. I will then present possible ways to mitigate such effects.
