In this paper, we examine two crucial aspects of quantum information processing: the dynamics of entanglement in atom-field interactions and the fidelity of quantum teleportation under nonlinear effects. We analyze entanglement and quantum entropic uncertainty in a system of two-level atoms coupled to a Fock-state cavity field, taking into account the effects of the Kerr medium and the Stark shift. Our findings reveal phenomena such as entanglement, sudden death, and revival, with these occurrences becoming more frequent at higher Kerr and Stark parameters. Furthermore, we investigate the dynamics of average fidelity in a quantum teleportation protocol, focusing on the roles of the input state angle θ and the nonlinear coupling strength χ1. Fideism exhibits periodic behavior, achieving optimal values in specific parameter settings, particularly when θ = π. These insights significantly enhance our understanding of quantum entanglement control and high-fidelity teleportation, which are essential for advancing quantum communication, cryptography, and measurement protocols.
In this paper, we examine two crucial aspects of quantum information processing: the dynamics of entanglement in atom-field interactions and the fidelity of quantum teleportation under nonlinear effects. We analyze entanglement and quantum entropic uncertainty in a system of two-level atoms coupled to a Fock-state cavity field, taking into account the effects of the Kerr medium and the Stark shift. Our findings reveal phenomena such as entanglement, sudden death, and revival, with these occurrences becoming more frequent at higher Kerr and Stark parameters. Furthermore, we investigate the dynamics of average fidelity in a quantum teleportation protocol, focusing on the roles of the input state angle θ and the nonlinear coupling strength χ1. Fideism exhibits periodic behavior, achieving optimal values in specific parameter settings, particularly when θ = π. These insights significantly enhance our understanding of quantum entanglement control and high-fidelity teleportation, which are essential for advancing quantum communication, cryptography, and measurement protocols.
In this paper, we investigate the dynamics of two two-level atoms interacting with a two-mode field inside an optical cavity, in presence of a nonlinear Kerr-like medium as well as the Stark shift. We derive the exact analytical solution of the time-dependent Schrödinger equation that provides a comprehensive framework for analyzing the system's quantum properties. To characterize the nonclassical features of the radiation field, we examine photon number distribution, second-order correlation function 𝑔2(0), squeezing properties, and Mandel's 𝑄𝑀 parameter. These properties reveal significant insights into the quantum statistical behaviour of the field and its deviation from classicality under different interaction regimes. In addition, we quantify the atom-atom entanglement using linear entropy which captures the mixedness of the atomic subsystem and elucidates the interplay between atom-atom interactions. The results highlight the crucial role of nonlinear interactions and the Stark shift in shaping the quantum correlations and nonclassical phenomena of the system.
This study investigates the quantum dynamics of three-level Stark-shifted atomic systems under the influence of a Nonlinear Kerr Medium (NLKM), focusing on the interplay between Quantum Fisher Information (QFI), Von Neumann Entropy (VNE), and photon-mediated interactions. By analyzing the temporal evolution of QFI (quantifying parameter estimation precision) and VNE (measuring quantum entanglement (QE), we demonstrate how Kerr nonlinearity (χ), Stark shifts (β), phase (ϕ), and photon numbers govern system behavior. Key findings reveal that lower χ values (e.g., [Formula: see text]) induce oscillatory QFI decay and rapid VNE growth, driven by atomic motion and NLKM interactions, with QFI peaks inversely correlated to VNE dips. Higher [Formula: see text] stabilizes both metrics, suppressing decoherence and entanglement fluctuations. Elevated photon numbers enhance stability by strengthening field-atom correlations, reducing oscillation amplitudes (particularly at low χ), and mitigating quantum fluctuations. The Stark effect (SE) amplifies energy-level shifts, while phase adjustments introduce asymmetries in quantum interference. These results highlight the system's tunability via [Formula: see text], and photon density. They position it as a versatile platform for quantum metrology and information processing, where precision, entanglement stability, and photon-mediated coherence are critical. Kerr interactions suppress long-time coherence and entanglement, while when [Formula: see text], Stark shifts can induce mild, transient quantum correlations. These dynamics are essential for controlling entanglement in cavity QED systems, especially when precise metrological performance is desired.
An entangled state, as an essential tool in quantum information processing, may be generated through the interaction between light and matter in cavity quantum electrodynamics. In this paper, we study the interaction between two two-level atoms and a two-mode field in an optical cavity enclosed by a medium with Kerr nonlinearity in the presence of a detuning parameter and Stark effect. It is assumed that the atom–field coupling and third-order susceptibility of the Kerr medium depend on the intensity of the light. In order to investigate the dynamics of the introduced system, we obtain the exact analytical form of the state vector of the considered atom–field system under initial conditions which may be prepared for the atoms (in a coherent superposition of their ground and upper states) and the fields (in a standard coherent state). Then, in order to evaluate the degree of entanglement between the subsystems, we investigate the dynamics of the entanglement by employing the entanglement of formation. Finally, we analyze in detail the influences of the Stark shift, the deformed Kerr medium, the intensity-dependent coupling, and also the detuning parameter on the behavior of this measure for different subsystems. The numerical results show that the amount of entanglement between the different subsystems can be controlled by choosing the evolved parameters appropriately.
We explore the dynamics of Quantum Fisher Information (QFI) and Von Neumann Entropy (VNE) in three-level stationary and moving Stark-shifted atomic systems influenced by a Nonlinear Kerr Medium (NLKM). QFI, which measures coherence and sensitivity to parameter changes, decreases over time due to decoherence, with slower decay at higher nonlinearity values. VNE, an indicator of quantum entanglement, increases over time, with stronger growth observed at lower nonlinearity valueThe Stark effect, caused by an external electric field, introduces energy level shifts that result in oscillatory behavior in both QFI and VNE. Stronger electric fields amplify these oscillations, enhancing sensitivity and entanglement dynamics. The system's phase significantly impacts its behavior, with symmetric patterns emerging at zero phase and more complex dynamics occurring at other phase values. In moving systems, atomic motion interacts with NLKM and Stark effects to produce periodic modulations in QFI and VNE. Lower nonlinearity values lead to pronounced oscillations, reflecting stronger quantum interactions, while higher values stabilize coherence. Peaks in QFI often align with dips in VNE, indicating a trade-off between precision and entanglement. Transient spikes in VNE highlight moments of enhanced quantum entanglement, while high QFI values signify robust coherence, critical for precision measurements. This study demonstrates the tunability of quantum systems through external field strength, nonlinearity, and phase, providing a framework for optimizing quantum sensing and exploring the fundamental dynamics of coherence and entanglement in quantum systems.
The possibility of teleporting a single-qubit system in an atomic system that interacts with a deformed cavity mode is being discussed. The average fidelity is used to investigate the quality of the teleported information in either ideal or deformed cavity. The quantum Fisher information is used as an estimator for the weight and phase angle parameters of the initial input state. The study shows that maximizing/minimizing the estimation degree and fidelity depends on the initial state settings of the atomic system, dipole–dipole coupling, and the estimated parameters. To maximize the information in the presence of a deformed cavity, one has to set large values of the atomic coupling dipole subsystem and reduce the deformation parameter.
The nonlinearity effect on the various formed quantum correlations between two atoms interacting locally with a bimodal cavity is explored in this work. The local quantum Fisher information, local quantum uncertainty, and negativity are used to investigate the quantum correlation’s sensitivity to the cavity modes characteristics. It is demonstrated that when the ratio of the Stark shift of the two modes increases, the atomic quantum correlations rise. During the time intervals of sudden death negativity entanglement, the three two-atom correlation quantifiers reveal that the two-atom system can contain local Fisher information and local uncertainty correlations. The Stark shift may be utilized to amplify the produced atomic correlation, while the Kerr-like medium can be used to suppress it. The regularity, the amount of generated atomic correlations, and their immunity to the Stark shift as well as the Kerr-like medium non-linearities are improved when the mean photon number is increased. As a result, the cavity modes’ nonlinear parameters might be utilized as a controller to optimize atomic quantum correlations.