Detuning and decoherence effects on atomic entanglement and coherence induced by nonlinear atom–field interactions

Abstract

This study investigates the intricate dynamics of entanglement, coherence, and purity in a two-atom-field interaction system under varying conditions including decoherence, field structure, detuning, and nonlinearity. By analyzing eight distinct scenarios involving coherent and even coherent field states, with and without detuning, in the presence or absence of Kerr type nonlinearity and phase decoherence, the study reveals how each factor individually and in combination governs the preservation or degradation of fundamental quantum properties. Under ideal conditions without decoherence, the system exhibits rich and structured quantum dynamics characterized by sustained entanglement, persistent coherence, and high purity. However, even minimal phase decoherence substantially deteriorates these features, highlighting the inherent fragility of quantum correlations. The field structure especially the photon number distribution in coherent and even coherent states adds complexity that enhances nonclassical effects but simultaneously increases susceptibility to environmental noise. Detuning disrupts atom field resonance, diminishing quantum coherence and entanglement, while Kerr type nonlinearity introduces irregular revival patterns that heighten the system’s sensitivity to decoherence. Additionally, small initial field intensity results in weak and fragmented quantum behavior, even in the absence of phase decoherence. Furthermore, introducing nonlinear atom field coupling particularly of the Kerr like form significantly alters the quantum dynamics. Even under resonant conditions, concurrence, first-order coherence, and purity are highly sensitive to both detuning and decoherence.