Optimizing fictitious states for Bell inequality violation in bipartite qubit systems with applications to the $t\overline{t}$ system

Journal Article · 07 June 2024 · Physical Review. D.

DOI: https://doi.org/10.1103/PhysRevD.109.116005 · OSTI ID:2474159

Cheng, Kun ; Han, Tao ; Low, Matthew

There is a significant interest in testing quantum entanglement and Bell inequality violation in high-energy experiments. Since the analyses in high-energy experiments are performed with events statistically averaged over phase space, the states used to determine observables depend on the choice of coordinates through an event-dependent basis and are thus not genuine quantum states, but rather “fictitious states.” We find that the basis which diagonalizes the spin-spin correlations is optimal for constructing fictitious states to test the violation of Bell’s inequality. This result is applied directly to the bipartite qubit system of a top and antitop produced at a hadron collider. We show that the beam axis is the optimal basis choice near the $t\overline{t}$ threshold production for measuring Bell inequality violation, while at high transverse momentum the basis that aligns along the momentum direction of the top is optimal. Published by the American Physical Society 2024

• Research Organization: Univ. of Pittsburgh, PA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• Grant/Contract Number: SC0007914
• OSTI ID: 2474159
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 11 Vol. 109; ISSN PRVDAQ; ISSN 2470-0010
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English