Experimental characterization of the hierarchy of quantum correlations in top quark pairs

Abstract

Recent results from the Large Hadron Collider have demonstrated quantum entanglement of top quark-antiquark pairs using the spin degrees of freedom. Based on the doubly differential measurement of the spin density matrix of the top quark and antiquark performed by the CMS collaboration in the helicity and beam bases, we evaluate a set of quantum observables, including discord, steerability, Bell correlation, and magic. These observables allow for a quantitative characterization of the quantum correlations present in a top quark-antiquark system, thus enabling an interpretation of collider data in terms of quantum states and their properties. Discord is observed to be greater than zero with a significance of more than 5 standard deviations ($\sigma$) in several regions of phase space, some of which correspond to separable quantum states. Evidence for steerability is established for the first time in a high-energy system, with a significance of more than 3$\sigma$. No Bell correlation is observed within the currently probed phase space, in agreement with the theoretical prediction. These results experimentally corroborate the hierarchy of quantum correlations in top quarks with discord being the most basic form of quantum correlation, followed by entanglement, steerability, and Bell correlation. The significance of nonzero magic, which is a complementary observable to the quantum correlation hierarchy, is found to exceed 5$\sigma$ in several regions of phase space.

arXiv comment11 pages, 4 figures

References in corpus (51)

• Polynomial-Time Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer
• An Introduction to PYTHIA 8.2
• Separability Criterion for Density Matrices
• Quantum Mechanics helps in searching for a needle in a haystack
• Introducing Quantum Discord
• A New Method for Combining NLO QCD with Shower Monte Carlo Algorithms
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• Bell nonlocality
• Steering, Entanglement, Nonlocality, and the EPR Paradox
• Separability criterion and inseparable mixed states with positive partial transposition
• A Positive-Weight Next-to-Leading-Order Monte Carlo for Heavy Flavour Hadroproduction
• Quantum Steering
• Quantum discord for general two--qubit states: Analytical progress
• Stabilizer Rényi entropy
• Top quark pair production and decay at hadron colliders
• Entanglement and quantum tomography with top quarks at the LHC
• Optimal measurements to access classical correlations of two-qubit states
• Top quark spin correlations at hadron colliders: Predictions at next-to-leading order QCD
• QCD-corrected spin analysing power of jets in decays of polarized top quarks
• Tracing CP violation in the production of top quark pairs by multiple TeV proton-proton collisions
• Quantum information with top quarks in QCD
• Quantum tops at the LHC: from entanglement to Bell inequalities
• Einstein-Podolsky-Rosen steering and the steering ellipsoid
• Observation of quantum entanglement in top-quark pairs using the ATLAS detector
• Improved tests of entanglement and Bell inequalities with LHC tops
• Quantum discord and steering in top quarks at the LHC
• Conformal field theories are magical
• Many-body magic via Pauli-Markov chains -- from criticality to gauge theories
• Quantum Chaos is Quantum
• Magic-state resource theory for the ground state of the transverse-field Ising model
• Constraining new physics in entangled two-qubit systems: top-quark, tau-lepton and photon pairs
• Observation of quantum entanglement in top quark pair production in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Signatures of Higgs Bosons in the Top Quark Decay Channel at Hadron Colliders
• A set of top quark spin correlation and polarization observables for the LHC: Standard Model predictions and new physics contributions
• Necessary and sufficient condition for steerability of two-qubit states by the geometry of steering outcomes
• Single T gate in a Clifford circuit drives transition to universal entanglement spectrum statistics
• A New Twist on Top Quark Spin Correlations
• Measurement of EPR-type flavour entanglement in Upsilon(4S)->B0 B0bar decays
• Quantum entanglement and top spin correlations in SMEFT at higher orders
• When the Machine Chimes the Bell: Entanglement and Bell Inequalities with Boosted $t\bar{t}$
• Stabilizer entropy dynamics after a quantum quench
• Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using lepton+jets events from proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Optimizing Fictitious States for Bell Inequality Violation in Bipartite Qubit Systems
• Quantum Information meets High-Energy Physics: Input to the update of the European Strategy for Particle Physics
• Magic-induced computational separation in entanglement theory
• Optimizing Entanglement and Bell Inequality Violation in Top Anti-Top Events
• Stabilizer entropy of quantum tetrahedra
• Doped stabilizer states in many-body physics and where to find them
• Necessary conditions for steerability of two qubits, from consideration of local operations
• From top quarks to enhanced quantum key distribution: A Framework for Optimal Predictability of Quantum Observables
• Characterization of the quantum state of top quark pairs produced in proton-proton collisions at $\sqrt{s}$ = 13 TeV using the beam and helicity bases