We study quantum-information aspects of neutron--proton scattering in the spin-space $M$ -matrix framework. Four representative classes of input states are considered, namely diagonal mixed states, separable pure states, general two-qubit pure states, and a special Schmidt-like entangled subclass. For each class, ensemble-averaged output mutual information, reduced-state linear entropy, negativity, and geometric quantum discord are calculated in the relative momentum-- scattering angle plane. The results show that the outgoing spin correlations are governed jointly by scattering kinematics and by the structure of the incoming quantum ensemble. Input states with stronger intrinsic coherence or entanglement give larger maxima and higher minima in the mutual information, negativity, and geometric quantum discord. The enhanced regions of the mutual information and geometric discord depend on the input states, while the negativity maximum remains concentrated in the high-momentum backward-scattering region. These results extend earlier studies based on product-state entanglement power and provide an ensemble-based description of how spin correlations in neutron--proton scattering arise from the interplay between input-state structure and scattering dynamics.We study quantum-information aspects of neutron--proton scattering in the spin-space $M$-matrix framework. Four representative classes of input states are considered, namely diagonal mixed states, separable pure states, general two-qubit pure states, and a special Schmidt-like entangled subclass. For each class, ensemble-averaged output mutual information, reduced-state linear entropy, negativity, and geometric quantum discord are calculated in the relative momentum-- scattering angle plane. The results show that the outgoing spin correlations are governed jointly by scattering kinematics and by the structure of the incoming quantum ensemble. Input states with stronger intrinsic coherence or entanglement give larger maxima and higher minima in the mutual information, negativity, and geometric quantum discord. The enhanced regions of the mutual information and geometric discord depend on the input states, while the negativity maximum remains concentrated in the high-momentum backward-scattering region. These results extend earlier studies based on product-state entanglement power and provide an ensemble-based description of how spin correlations in neutron--proton scattering arise from the interplay between input-state structure and scattering dynamics.

nucl-thCross-listedarXiv:2608.30356Sep 1, 20261 citation

Quantum Discord of Certain Two-Qubit States

Jianming Zhou, Xiaoli Hu, Naihuan Jing

arXiv:2004.11668International Journal of Theoretical PhysicsNov 19, 201914 citations

Quantum correlations in two interacting atom ensembles

Yuyu Zhang, Chen Wang

The power-law scaling behaviours of the quantum discord and the scaled concurrence are presented in two coupled atom ensembles, which exhibit the Dicke-like quantum phase transition. In the super-excitation phase, the quantum discord reaches its maximum beyond the critical point and then decreases monotonically, which is ascribed to the double-degenerated ground state in the strong coupling limit. However, the scaled concurrence exhibits the maximum atomic quantum entanglement at the critical point. Moreover, we find that the persistence of the quantum discord is suppressed by different asymmetric effects in the super-excitation phase.The power-law scaling behaviours of the quantum discord and the scaled concurrence are presented in two coupled atom ensembles, which exhibit the Dicke-like quantum phase transition. In the super-excitation phase, the quantum discord reaches its maximum beyond the critical point and then decreases monotonically, which is ascribed to the double-degenerated ground state in the strong coupling limit. However, the scaled concurrence exhibits the maximum atomic quantum entanglement at the critical point. Moreover, we find that the persistence of the quantum discord is suppressed by different asymmetric effects in the super-excitation phase.

Journal of Physics B Atomic Molecular and Optical PhysicsApr 24, 20133 citations

Quantum discord of states arising from graphs

Supriyo Dutta, Bibhas Adhikari, Subhashish Banerjee

arXiv:1702.06360Quantum Information ProcessingJun 17, 20179 citations

Coherence of Quantum Ensemble as a Dual to Uncertainty for a Single Observable

Dmitry Anatolevich Kronberg

The coherence of an ensemble of quantum states is considered — a quantity having a similarity with the uncertainty of the quantum observable that arises from the entropic uncertainty relations. We give estimates for the coherence of the ensemble through the uncertainty of the dual observable and the weak uncertainty of the observable through the coherence of the ensemble. It is shown that this numerical characteristic is closely connected with the relative entropy of discord for the corresponding classical-quantum state.The coherence of an ensemble of quantum states is considered — a quantity having a similarity with the uncertainty of the quantum observable that arises from the entropic uncertainty relations. We give estimates for the coherence of the ensemble through the uncertainty of the dual observable and the weak uncertainty of the observable through the coherence of the ensemble. It is shown that this numerical characteristic is closely connected with the relative entropy of discord for the corresponding classical-quantum state.

Lobachevskii Journal of MathematicsOct 1, 20196 citations

QUANTUM DISCORD IN A SPIN SYSTEM WITH SYMMETRY BREAKING

Bruno Tomasello, Davide Rossini, Alioscia Hamma +1 more

WORLD SCIENTIFIC eBooksJun 25, 20130 citations

Quantum information in neutron-proton scattering from the

M

matrix

We study quantum-information aspects of neutron--proton scattering in the spin-space

M

-matrix framework. Four representative classes of input states are considered, namely diagonal mixed states, separable pure states, general two-qubit pure states, and a special Schmidt-like entangled subclass. For each class, ensemble-averaged output mutual information, reduced-state linear entropy, negativity, and geometric quantum discord are calculated in the relative momentum-- scattering angle plane. The results show that the outgoing spin correlations are governed jointly by scattering kinematics and by the structure of the incoming quantum ensemble. Input states with stronger intrinsic coherence or entanglement give larger maxima and higher minima in the mutual information, negativity, and geometric quantum discord. The enhanced regions of the mutual information and geometric discord depend on the input states, while the negativity maximum remains concentrated in the high-momentum backward-scattering region. These results extend earlier studies based on product-state entanglement power and provide an ensemble-based description of how spin correlations in neutron--proton scattering arise from the interplay between input-state structure and scattering dynamics.