This paper investigates the evolution of global quantum discord (GQD) and quantum Fisher information (QFI) of the interaction of multiple two-level atomic systems (TLS) with a single thermal field mode and a non-linear Kerr medium (NLKM) considering the cases of intrinsic decoherence and its absence. Results indicate that increasing the number of atomic systems (N) while maintaining the NLKM parameter constant ? leads to higher GQD and QFI values for both intrinsic intrinsic decoherence cases. With rising ?, the GQD values decrease but the oscillation rate of the GQD increases. The presence of intrinsic decoherence does not significantly reduce the GQD quasi-static value compared to the no-decoherence scenario for certain ? values. At the same time, a different trend is observed for higher ? values. The average QFI value rises with reduced oscillation amplitudes for higher ? values and larger N subsystems. Unlike the GQD, higher ? values aid in maintaining average QFI in the presence of intrinsic decoherence. For moving TLS, changing ? does not alter the oscillation periods of the GQD and QFI. The GQD values decrease with increased ? in the moving system case, while the QFI improves with higher ? values. Additionally, higher average thermal photons within the system suppress the GQD and QFI values and decrease oscillation amplitudes for both quantifiers.
This paper investigates the evolution of global quantum discord (GQD) and quantum Fisher information (QFI) of the interaction of multiple two-level atomic systems (TLS) with a single thermal field mode and a non-linear Kerr medium (NLKM) considering the cases of intrinsic decoherence and its absence. Results indicate that increasing the number of atomic systems (N) while maintaining the NLKM parameter constant ? leads to higher GQD and QFI values for both intrinsic intrinsic decoherence cases. With rising ?, the GQD values decrease but the oscillation rate of the GQD increases. The presence of intrinsic decoherence does not significantly reduce the GQD quasi-static value compared to the no-decoherence scenario for certain ? values. At the same time, a different trend is observed for higher ? values. The average QFI value rises with reduced oscillation amplitudes for higher ? values and larger N subsystems. Unlike the GQD, higher ? values aid in maintaining average QFI in the presence of intrinsic decoherence. For moving TLS, changing ? does not alter the oscillation periods of the GQD and QFI. The GQD values decrease with increased ? in the moving system case, while the QFI improves with higher ? values. Additionally, higher average thermal photons within the system suppress the GQD and QFI values and decrease oscillation amplitudes for both quantifiers.
In this paper, we explore the dynamics of the global quantum discord (GQD) and quantum Fisher information (QFI) of a multipartite two-level stationary and moving atomic system under the Stark shift effect. The system interacts with a thermal field with a different number of average thermal photons. For a fixed Stark parameter value, the GQD magnitudes increase as the system size (N) increases for both static and moving atomic systems. However, in the instance of a stationary atomic system and lower Stark parameter values, the QFI preserves a constant magnitude for different N values. When atomic motion is taken, the quantifier dynamics exhibit periodic oscillations. Additionally, increasing the Stark parameter led to a suppression in the magnitude of both GQD and QFI. With in the sight of intrinsic decoherence (ID), the quantifiers show a damping in their oscillations. Interestingly, the atomic motion assists to mitigate the damping effects caused by ID. Moreover, if the average thermal photons are increased, the magnitude of the GQD and QFI are decreased.
In this paper, we investigate the interplay between quantum correlations, quantified by global quantum discord (GQD), and quantum Fisher information (QFI) within a multipartite two-level system interacting with a single-mode Fock field. Our model incorporates Kerr-like nonlinearity, parametric amplification, and intrinsic decoherence. By varying the photon-number cutoff, system dimensionality, and parametric amplification strength under different magnitudes of the Kerr effect, we analyze how these factors influence correlation dynamics and parameter estimation precision. We observe a threshold-like behavior in the photon number during the transition from a decoherence-dominated regime to a coherence-enhanced regime. These results show a balance between the amplification strength and Kerr effects, and reveal that GQD and QFI exhibit different levels of robustness. These findings provide valuable insights for optimizing nonlinear atom-field configurations in quantum information and quantum metrology applications.
Abstract Dynamical evolution of global quantum discord (GQD) and von Neumann entropy (VNE) is studied for N two-level atomic system (TLS) (two, three and four TLS). The system interacts with the single mode Fock field and the cavity is filled with the non-linear Kerr medium (NLKM). It is seen that for large values of the Kerr parameter, the GQD and VNE show periodic behavior which leads to the sudden death and birth of the quantum entanglement (QE). It is found that the oscillations of the GQD is suppressed for the initial mixed state. The VNE has non-zero values of quantum interference throughout the dynamics of the system for initial mixed states. It is also found that the multipartite systems show sustained response to the QE during the time evolution. Moreover, the GQD and VNE are notably affected in the presence of the NLKM and affected for the entire range of Kerr values as we increase the number of photons in the cavity. Furthermore, for both initial pure and mixed states, the periodic behavior of the GQD and VNE is almost the same for the case of moving TLS. The sudden death and birth of QE is more prominent for moving TLS case. The atomic motion is favorable to sustain the QE in the atomic systems in a NLKM.
In this work, we study the dynamics of global quantum discord and quantum Fisher information in a multipartite system of two-level atoms interacting with a coherent field. The model includes parametric amplification, Kerr-type nonlinearity, and intrinsic decoherence to examine how these effects control quantum correlations and parameter-estimation sensitivity. The results show that, without intrinsic decoherence, both quantities exhibit rapid oscillations with clear collapse and revival behavior. Strong Kerr nonlinearity and strong parametric amplification enhance global quantum discord, while quantum Fisher information becomes maximum under a suitable balance of Kerr nonlinearity and amplification strength. Increasing the number of atoms generally strengthens global quantum discord but does not always improve quantum Fisher information. Intrinsic decoherence damps the oscillations and drives the system toward steady-state behavior.
In this paper, we have proposed the numerical calculations to study the quantum entanglement (QE) of moving two-level atom interacting with a coherent and the thermal field influenced by intrinsic decoherence (ID), Kerr medium (non-linear) and the Stark effect. The wave function of the complete system interacting with a coherent and the thermal field is calculated numerically affected by ID, Kerr (non-linear) and Stark effects. It has been seen that the Stark, Kerr, ID and the thermal environment have a significant effect during the time evolution of the quantum system. Quantum Fisher information (QFI) and QE decrease as the value of the ID parameter is increased in the thermal field without the atomic movement. It is seen that QFI and von Neumann entropy (VNE) show an opposite and periodic response in the presence of atomic motion. The non-linear Kerr medium has a more prominent and significant effect on the QE as the value of the Kerr parameter is decreased. At smaller values of the non-linear Kerr parameter, the VNE increases, however, QFI decreases, so QFI and VNE have a monotonic connection with one another. As the value of the Kerr parameter is increased, the effect of non-linear Kerr doesn’t stay critical on both QFI and QE. However, a periodic response of QE is seen because of the atomic movement which becomes modest under natural impacts. Moreover, it has been seen that QFI and QE rot soon at the smaller values of the Stark parameter. However, as the value of the Stark parameter is increased, the QFI and QE show periodic response even when the atomic movement is absent.
We have investigated numerically the dynamics of quantum Fisher information (QFI) and quantum entanglement (QE) of a two moving two-level atomic systems interacting with a coherent and thermal field in the presence of intrinsic decoherence (ID) and Kerr (non-linear medium) and Stark effects. The state of the entire system interacting with coherent and thermal fields is evaluated numerically under the influence of ID and Kerr (nonlinear) and Stark effects. QFI and von Neumann entropy (VNE) decrease in the presence of ID when the atomic motion is neglected. QFI and QE show an opposite response during its time evolution in the presence of a thermal environment. QFI is found to be more susceptible to ID as compared to QE in the presence of a thermal environment. The decay of QE is further damped at greater time-scales, which confirms the fact that ID heavily influences the system’s dynamics in a thermal environment. However, a periodic behavior of entanglement is observed due to atomic motion, which becomes modest under environmental effects. It is found that a non-linear Kerr medium has a prominent effect on the VNE but not on the QFI. Furthermore, it has been observed that QFI and QE decay soon under the influence of the Stark effect in the absence of atomic motion. The periodic response of QFI and VNE is observed for both the non-linear Kerr medium and the Stark effect in the presence of atomic motion. It is observed that the Stark, Kerr, ID, and thermal environment have significant effects during the time evolution of the quantum system.