Phenomenological Model of Temperature-Dependent Coherence and Nonlocality in Quantum Systems:

Andrey Anatoljevich Grib, Waldyr A. Rodrigues

Chakir Fikri

Abstract The conceptual tension between quantum nonlocality and relativistic causality motivates scenarios in which Lorentz invariance is an emergent rather than fundamental symmetry. Within such scenarios, optical propagation may retain a weak dependence on properties of an underlying quantum substrate, including the coherence of nearby quantum systems. We introduce a phenomenological model in which optical propagation depends weakly on the quantum coherence of a nearby ancillary control system. To test this hypothesis, we propose a quantum-controlled Mach–Zehnder interferometric (MZI) protocol comparing coherent and incoherent ancillary states having identical populations. Standard quantum mechanics predicts identical photon-counting statistics in both configurations, whereas the proposed phenomenological model predicts additional stochastic phase fluctuations leading to an excess phase-noise variance in the coherent-control configuration. We derive the corresponding statistical sensitivity, discuss possible implementations based on state-of-the-art fiber MZIs, and estimate illustrative experimental bounds on the coherence–propagation coupling parameter.

Abner Shimony

S. Bhuvaneswari, R. Muthuganesan, R. Radha

We investigate the behaviors of thermal entanglement, quantum correlation beyond entanglement namely, measurement-induced nonlocality (MIN) and coherence in a nickel radical molecular magnet (Et3NH)[Ni(hfac)2L], whose spin-spin interactions are well described by the Heisenberg model. Using experimentally estimated coupling parameters, we compute the thermal state of the system and analyze the dependence of quantum resources on temperature and magnetic field. The results indicate that the quantum resources of the nickel-radical molecular magnet persist even at room temperature. We show that while negativity (the entanglement measure) rapidly vanishes with increasing temperature and magnetic field, measurement-induced nonlocality and quantum coherence remain comparatively more stable and persist in regions where entanglement is absent. These results highlight the significance of nonclassical correlations beyond entanglement in thermally activated spin systems and suggest that such molecular magnets could serve as viable platforms for quantum information processing in realistic conditions.

N.A. Gromov, Костяков Игорь Владимирович, Куратов Василий Васильевич

Huai-Xin Lu, Yingde Li

This paper studies the dynamics of nonlocality for a bosonic entangled coherent state in a phase damping model. The density operator of the system is solved by using a superoperator method. The dynamics of nonlocality for the bosonic entangled coherent state is uncovered by the Bell operator based on the pseudospin operator of a light field. The dynamics of the nonlocality for this state has also been studied by other Bell operators. The result of the numerical calculations of the Bell function shows that the quantum nonlocality heavily depends on the chosen Bell operator.