Quantum discord and steering offer crucial insights into the non-classical nature of hyperon-antihyperon pairs, a massive two-qubit system produced in high energy electron-positron annihilation. This work theoretically investigates the generation and control of these quantum correlations by leveraging longitudinal and transverse polarization of lepton beams. By exploiting the joint spin density matrix of hyperon pairs, the sensitivity of quantum discord and steering to the beam polarization degree are numerically quantified. Our analysis reveals distinct angular regimes where beam polarization can enhance steering and discord. Hierarchy of different quantum correlations are examined under the case of polarized lepton beams by constructing a measure in the spirit of entanglement of formation. It is confirmed that quantum discord remain non-zero even in regions with vanishing entanglement corresponding to separable states, controlled via transversely polarized beams. As an experimentally tunable parameter, beam polarization offers an effective means to manipulate the quantum correlation of hyperon-antihyperon systems, thereby providing a practical route for preparing and probing quantum states in high-energy particle physics.
Quantum discord and steering offer crucial insights into the non-classical nature of hyperon-antihyperon pairs, a massive two-qubit system produced in high energy electron-positron annihilation. This work theoretically investigates the generation and control of these quantum correlations by leveraging longitudinal and transverse polarization of lepton beams. By exploiting the joint spin density matrix of hyperon pairs, the sensitivity of quantum discord and steering to the beam polarization degree are numerically quantified. Our analysis reveals distinct angular regimes where beam polarization can enhance steering and discord. Hierarchy of different quantum correlations are examined under the case of polarized lepton beams by constructing a measure in the spirit of entanglement of formation. It is confirmed that quantum discord remain non-zero even in regions with vanishing entanglement corresponding to separable states, controlled via transversely polarized beams. As an experimentally tunable parameter, beam polarization offers an effective means to manipulate the quantum correlation of hyperon-antihyperon systems, thereby providing a practical route for preparing and probing quantum states in high-energy particle physics.
Hyperon-antihyperon pairs produced from electron-positron annihilations provide a promising platform for exploring quantum-information properties in particle physics. In this work, we analyze quantum steering and quantum discord in hyperon-antihyperon systems produced from e + e − annihilations, based on the X -shaped spin density matrix reconstructed via quantum state tomography. We show that the behaviors of these correlations differ from those observed in elementary particle-antiparticle systems such as top quarks and τ leptons, owing to the polarization effects specific to hyperon decays. From the results, we examine the hierarchy of quantum correlations in hyperon-antihyperon systems, Bell nonlocality ⊂ steering ⊂ entanglement ⊂ discord . We also discuss the role of experimental loopholes and the impact of quantum decoherence in collider-based studies of quantum correlations.
The hyperon-antihyperon pairs produced in electron-positron annihilation as a massive two-qubit quantum system can be used to study the quantum correlations at high energies. This paper is theoretically dedicated to how polarization of lepton beams manipulates the Bell nonlocality and entanglement of hyperon pair systems. The response of the Clauser–Horne–Shimony–Holt parameter, concurrence, and negativity to the polarization degree of the beam is numerically calculated by exploiting the joint spin density matrix of hyperon-antihyperon pairs. Different influences of longitudinal and transverse polarization of beams on entanglement are found and compared. The results provide alternative perspectives for the decay of charmonium to hyperon pairs.
Abstract Hyperon-antihyperon pairs produced in high-energy electron-positron annihilation constitute a naturally spin-entangled system in the high-energy regime. Recently, a probabilistic amplification of entanglement, termed autodistillation, has been found in the daughter baryon-antibaryon pairs from hyperon decay and is constrained by an upper boundary. This work demonstrates that the quantum entanglement in this process may be accompanied by a decrease, constrained by a lower boundary, but it will not be completely lost. Thus, the entanglement of these systems undergoes redistribution within the phase space during the sequential decays of hyperons, highlighting the important role of hyperon polarization. By using the explicit spin density matrix of baryon pairs, it is also found that the quantumness of the system, characterized by quantum discord, always has the possibility to increase during decay processes, even when entanglement evaluated by concurrence and negativity does not increase.
Quantum discord, as introduced by Olliver and Zurek [Phys. Rev. Lett. 88, 017901 (2001)], is a measure of the discrepancy between two natural yet different quantum analogs of the classical mutual information. This notion characterizes and quantifies quantumness of correlations in bipartite states from a measurement perspective, and is fundamentally different from the various entanglement measures in the entanglement vs separability paradigm. The phenomenon of nonzero quantum discord is a manifestation of quantum correlations due to noncommutativity rather than due to entanglement, and has interesting and significant applications in revealing the advantage of certain quantum tasks. We will evaluate analytically the quantum discord for a large family of two-qubit states, and make a comparative study of the relationships between classical and quantum correlations in terms of the quantum discord. We furthermore compare the quantum discord with the entanglement of formation, and illustrate that the latter may be larger than the former, although for separable states, the entanglement of formation always vanishes and thus is less than the quantum discord.
Quantum coherence, a cornerstone of quantum mechanics, is of paramount importance for quantum information protocols. However, maintaining coherence in elementary particle systems presents significant challenges. In this work, we investigate quantum coherence and quantum correlations in the e + e − → Λ Λ ¯ processes at BESIII using experimentally feasible parameters, where Λ and Λ ¯ denote the spin- 1 / 2 hyperon and its antihyperon, respectively. We analyze the dependence of quantum coherence and quantum correlations on the scattering angle φ . Notably, these resources reach their maximum at φ = π / 2 . We demonstrate that classical correlations can significantly delay the decay of quantum correlations and coherence. This study underscores the importance of understanding the interplay between classical and quantum correlations in high-energy particle physics, particularly in the context of hyperon-antihyperon interactions explored in the BESIII experiment. Furthermore, we discuss the hierarchy of quantum resources (quantum steering, entanglement of formation, geometric quantum discord, and quantum coherence) in both Markovian and non-Markovian regimes. This result could have potential applications in quantum information processing and high-energy physics.
A bstract There has been an increasing interest in exploring quantities associated with quantum information at colliders. We perform a detailed analysis describing how to measure the quantum discord in the top anti-top quantum state at the Large Hadron Collider (LHC). While for pure states, quantum discord, entanglement, and Bell nonlocality all probe the same correlations, for mixed states they probe different aspects of quantum correlations. The quantum discord, in particular, is interesting because it aims to encapsulate all correlations between systems that cannot have a classical origin. We employ two complementary approaches for the study of the top anti-top system, namely the decay method and the kinematic method. We highlight subtleties associated with measuring discord for reconstructed quantum states at colliders. Usually quantum discord is difficult to compute due to an extremization that must be performed. We show, however, that for the tt t t ¯ system this extremization can be performed analytically and we provide closed-form formulas for the quantum discord. We demonstrate that with current LHC datasets, quantum discord can be observed at 3 . 6 – 5 . 7 σ , depending on the signal region, with the decay method and can be measured at a precision of 0 . 1 – 0 . 2% with the kinematic method. At the high luminosity LHC, the observation of quantum discord is expected to be > 5 σ using both the decay and kinematic methods and can be measured with a precision of 5% with the decay method and 0 . 05% with the kinematic method. Additionally, we identify the kinematic cuts at the LHC to isolate the tt t t ¯ state that is separable but has non-zero discord. By systematically investigating quantum discord for the first time through a detailed collider analysis, this work expands the toolkit for quantum information studies in particle physics and lays the groundwork for deeper insights into the quantum properties in high-energy collisions.