Saeed Haddadi

We comment on the recent analysis reported in [], where quantum coherence, entanglement, steering, and non-Markovian dynamics were investigated in the process e + e − → Λ Λ ¯ . While the mathematical framework employed in that work may be formally well defined, we argue that several physical assumptions underlying its interpretation require further clarification. In particular, the treatment of the produced hyperon-antihyperon pair as an open bipartite system evolving under correlated quantum channels does not appear to follow naturally from the physical properties of the process. Moreover, the operational meaning of quantum steering and non-Markovianity in this relativistic unstable-particle system remains unclear due to the absence of controllable local measurements, engineered environments, and experimentally accessible dynamical maps. We emphasize that quantum-information-inspired observables can provide useful characterizations of spin correlations in high-energy reactions when their operational interpretation and physical assumptions are carefully specified. Our purpose is therefore not to question the mathematical consistency of the analyzed formalism, but rather to clarify the physical limitations associated with its interpretation in the Λ Λ ¯ system.

Quantum Energy Teleportation (QET) is a protocol in which a remote measurement activates locally inaccessible ergotropy stored in the ground state of a many-body system by consuming preexisting entanglement and a classical communication channel. Nevertheless, the implementation of QET is severely impeded by the fundamental locality of gapped many-body systems, where the exponential clustering of ground-state correlations restricts energy extraction to microscopic scales. In this work we address this scalability challenge within the framework of the one-dimensional anisotropic XY model. We provide a rigorous characterization of a monolithic measurement-induced strategy, demonstrating that while bulk projective measurements can theoretically induce long-range couplings, the approach is rendered physically untenable by exponentially diverging thermodynamic costs and vanishing success probabilities. To circumvent this impasse, we propose and analyze a hierarchical quantum repeater architecture adapted for energy teleportation. By orchestrating heralded entanglement generation, iterative entanglement purification, and nested entanglement swapping, our protocol effectively counteracts the fidelity degradation inherent in noisy quantum channels. We establish that this architecture fundamentally alters the operational resource scaling from exponential to polynomial, providing a physically permissible pathway for ground-state ergotropy activation at arbitrary distances. The significance lies not in net energy gain but in establishing long-range QET as a viable protocol for remote quantum control and resource distribution.

We investigate the quantum correlations in an axially symmetric hybrid qubit–qutrit system subjected to different noisy environments. We first introduce a physical model and analyze its Hamiltonian structure, emphasizing the role of hybrid dimensionality and axial symmetry. The effects of decoherence are then examined under two local noise mechanisms, namely dephasing and phase-flip channels, acting on the qubit and qutrit subsystems in both symmetric and asymmetric configurations. Quantum correlations are quantified using negativity to capture entanglement and quantum discord based on linear entropy to characterize more general nonclassical correlations. Our results show that both thermal fluctuations and phase noise lead to a monotonic degradation of quantum correlations, with increasing temperature accelerating coherence loss and inducing entanglement sudden death at finite temperatures. While negativity vanishes abruptly under sufficiently strong noise, quantum discord persists beyond the entanglement threshold, revealing residual quantum correlations in mixed states. We further demonstrate that asymmetric noise configurations significantly enhance the robustness of both entanglement and discord by partially shielding coherence in the less affected subsystem. A comparative analysis reveals that phase-flip noise is more destructive than pure dephasing, leading to faster suppression of quantum correlations.

We study quantum coherence in top-antitop production at the LHC by comparing Standard Model predictions with CMS data across different kinematic regimes. Theory and experiment are statistically consistent in the near-threshold and boosted central regions, confirming that the spin-density framework captures the dominant helicity-interference structure. The intermediate-mass window shows a noticeable deviation, indicating enhanced sensitivity to radiative QCD effects. This work reinterprets measured spin-correlation data within a quantum-coherence framework, thereby introducing coherence as a complementary and experimentally grounded probe of the Standard Model spin structure and a potentially sensitive diagnostic of new-physics effects in the top-quark sector.

We reveal the noncyclic Pancharatnam phase—arising from the coherent system-meter interaction—as a fundamental criterion that governs the optimal performance of quantum compression channels in postselected metrology. This phase embodies a geometric connection that enables precise control over the parallel evolution of the meter state, thereby maximizing the quantum Fisher information per trial and achieving lossless compression channels. Remarkably, fine-tuning the postselection parameter just below this optimal phase incurs substantial information loss, whereas tuning it just above fully suppresses undesired parallel evolution, enhancing information retention beyond that achievable in postselected protocols lacking Pancharatnam phase effects. We further reveal that leveraging qudit-meter states can unlock a substantial additional enhancement. These findings establish the Pancharatnam phase as a geometric benchmark, guiding the design of high-precision quantum parameter estimation protocols.

Quantum Energy Teleportation (QET) constitutes a paradigm-shifting protocol that permits the activation of local vacuum energy through the consumption of pre-existing entanglement and classical communication. Nevertheless, the implementation of QET is severely impeded by the fundamental locality of gapped many-body systems, where the exponential clustering of ground-state correlations restricts energy extraction to microscopic scales. In this work, we address this scalability crisis within the framework of the one-dimensional anisotropic XY model. We initially provide a rigorous characterization of a monolithic measurement-induced strategy, demonstrating that while bulk projective measurements can theoretically induce long-range couplings, the approach is rendered physically untenable by exponentially diverging thermodynamic costs and vanishing success probabilities. To circumvent this impasse, we propose and analyze a hierarchical quantum repeater architecture adapted for energy teleportation. By orchestrating heralded entanglement generation, iterative entanglement purification, and nested entanglement swapping, our protocol effectively counteracts the fidelity degradation inherent in noisy quantum channels. We establish that this architecture fundamentally alters the operational resource scaling from exponential to polynomial. This proves, for the first time, the physical permissibility and computational tractability of activating vacuum energy at arbitrary distances. The significance lies not in net energy gain, but in establishing long-range QET as a viable protocol for remote quantum control and resource distribution.

We investigate the quantum correlations in an axially symmetric hybrid qubit-qutrit system subjected to different noisy environments. We first introduce a physical model and analyze its Hamiltonian structure, emphasizing the role of hybrid dimensionality and axial symmetry. The effects of decoherence are then examined under two local noise mechanisms, namely dephasing and phase-flip channels, acting on the qubit and qutrit subsystems in both symmetric and asymmetric configurations. Quantum correlations are quantified using negativity to capture entanglement and quantum discord based on linear entropy to characterize more general nonclassical correlations. Our results show that both thermal fluctuations and phase noise lead to a monotonic degradation of quantum correlations, with increasing temperature accelerating coherence loss and inducing entanglement sudden death at finite temperatures. While negativity vanishes abruptly under sufficiently strong noise, quantum discord persists beyond the entanglement threshold, revealing residual quantum correlations in mixed states. We further demonstrate that asymmetric noise configurations significantly enhance the robustness of both entanglement and discord by partially shielding coherence in the less affected subsystem. A comparative analysis reveals that phase-flip noise is more destructive than pure dephasing, leading to faster suppression of quantum correlations.