Curator's Take
This article represents a fascinating convergence of particle physics and quantum information theory, demonstrating how Higgs boson decays can serve as a natural laboratory for studying quantum entanglement at the most fundamental level. The researchers show that even when accounting for complex higher-order corrections from quantum chromodynamics and electroweak interactions, the quantum correlations in these particle decays maintain their essential two-qutrit structure, making them viable probes for quantum tomography experiments. What makes this particularly exciting is that it opens up the possibility of using high-energy particle collisions at facilities like the Large Hadron Collider to study quantum information phenomena that are typically explored in controlled laboratory settings with individual atoms or photons. The work provides crucial theoretical groundwork for experimentalists who want to extract quantum information from particle physics data, potentially offering new ways to test our understanding of both the Standard Model and quantum mechanics itself.
— Mark Eatherly
Summary
Angular correlations in Higgs decays to electroweak gauge bosons, $h \to ZZ^*, WW^*$, provide a powerful probe of both new physics effects and quantum information observables. We present a systematic study of semi-leptonic decays $h \to V V^* \to \ell^+\ell^- q\bar{q}$ and $\ell^\pm ν_\ell q\bar{q}'$, including finite final state fermion masses, NLO QCD, and NLO electroweak corrections. We show that finite final state quark masses can induce effects that go beyond the two-qutrit description in more inclusive regimes, while remaining controllable with suitable kinematic selections. QCD corrections lead to modest percent-level shifts, whereas electroweak corrections can significantly modify the angular structure, particularly in the $h\to ZZ^*$ channels. We assess the impact of these effects on the reconstructed density matrix and entanglement measures, finding that, while they modify the angular observables, semi-leptonic channels retain an effective two-qutrit description.