REVIEW 12 cited by
Quantum information with top quarks in QCD
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
abstract
Top quarks represent unique high-energy systems since their spin correlations can be measured, thus allowing to study fundamental aspects of quantum mechanics with qubits at high-energy colliders. We present here the general framework of the quantum state of a top-antitop ($t\bar{t}$) quark pair produced through quantum chromodynamics (QCD) in a high-energy collider. We argue that, in general, the total quantum state that can be probed in a collider is given in terms of the production spin density matrix, which necessarily gives rise to a mixed state. We compute the quantum state of a $t\bar{t}$ pair produced from the most elementary QCD processes, finding the presence of entanglement and CHSH violation in different regions of phase space. We show that any realistic hadronic production of a $t\bar{t}$ pair is a statistical mixture of these elementary QCD processes. We focus on the experimentally relevant cases of proton-proton and proton-antiproton collisions, performed at the LHC and the Tevatron, analyzing the dependence of the quantum state with the energy of the collisions. We provide experimental observables for entanglement and CHSH-violation signatures. At the LHC, these signatures are given by the measurement of a single observable, which in the case of entanglement represents the violation of a Cauchy-Schwarz inequality. We extend the validity of the quantum tomography protocol for the $t\bar{t}$ pair proposed in the literature to more general quantum states, and for any production mechanism. Finally, we argue that a CHSH violation measured in a collider is only a weak form of violation of Bell's theorem, necessarily containing a number of loopholes.
Forward citations
Cited by 12 Pith papers
-
Qubit-qubit-qutrit quantum correlations in $H \to f \bar f V$
In h→τ^-τ^+ Z decays, the spin state is genuinely qubit-qubit-qutrit entangled almost everywhere, violates Bell inequalities throughout, and carries up to 1.95 bits of non-local magic.
-
Quantum detection of CP violation in the $t\bar{t}$ system: tomography
Polar-angle tomography reconstructs the ttbar production density matrix while b–lepton azimuthal sine modulations linearly probe CP-odd Wtb decay couplings, separating production from decay CP violation.
-
Quantum detection of CP violation in the $t\bar{t}$ system: production
CP-odd SMEFT top interactions appear as ΔB and antisymmetric C_A in the tt̄ production density matrix; direct markers beat most QI measures for CP sensitivity at LHC and FCC-ee.
-
Experimental prospects for quantum decoherence measurements at colliders
Hard final-state radiation measurably destroys the spin entanglement of fermion-antifermion pairs, and the effect should already be visible in LHC ttbar+jet and Belle II tau+tau-gamma data.
-
Quantum Tomography and Entanglement in Semi-Leptonic $h\to VV^*$ Decays at Higher Orders
Semi-leptonic h→VV* decays retain an effective two-qutrit quantum description under NLO QCD and electroweak corrections, unlike the fully leptonic h→4ℓ channel.
-
Extracting a Toponium Signal at the LHC with Spin and Quantum Information Tools
Spin and quantum-information observables add only marginal statistical power beyond kinematic variables for isolating toponium in near-threshold top-pair events, but improve interpretability.
-
Experimental characterization of the hierarchy of quantum correlations in top quark pairs
LHC top-quark data show quantum discord at >5σ, first evidence for steering at >3σ, no Bell correlations, and nonzero magic.
-
Parameter Inference from Final-State Entanglement in Higgs Decays
With a spin/color-weighted entanglement entropy built from Higgs branching ratios, the Standard Model Higgs and W masses sit near the global maximum, and the preferred coupling ratio is SM-like.
-
Entanglement, Yang-Mills, and the Scattering Matrix as an SU(N)-equivariant Kernel
SU(N) symmetry fixes the entangling power of 2→2 scattering: Yang-Mills adjoint scattering has a group-only entanglement maximum at 90° (3/4 for SU(2), ≈0.91 for SU(3)), and maximal-entanglement preservation selects t...
-
Spin versus Magic: Lessons from Gluon and Graviton Scattering
For 2 to 2 scattering of massless spin-1/2 to spin-2 particles, the averaged generated magic decreases monotonically with spin, with maxima well below the two-qubit upper bound.
-
Quantum spin correlations in $Z^\prime$-mediated $t\bar{t}$ production at future lepton colliders
Quantum spin observables of t-bar-t pairs at future lepton colliders can distinguish chiral U(1)_X Z′ charge assignments, and polarized e−e+ beams isolate left- vs right-handed lepton couplings.
-
Colliders are Testing neither Locality via Bell's Inequality nor Entanglement versus Non-Entanglement
Collider measurements of final-state momenta alone cannot certify Bell nonlocality or entanglement, because the measured angular distribution is itself a local hidden variable model.
Discussion (0). Sign in to comment.