Quantum Fisher information of N-level atoms under the influence of the thermal field and the Stark effect

This study investigates the quantum features of quantum entanglement (QE) in N-level atomic systems interacting with the thermal state subjected to varying Stark shift (SS) parameters. The N-level atomic system does not move in the presence of the SS interacting with the electromagnetic field. It is observed that a larger value of the SS parameter influences the quantum Fisher information (QFI) of 5-level atomic systems and increases the value of QFI of the 5-level atoms compared to 3- and 4-level atomic systems. The von Neumann entropy (VNE) also increases for the 5-level atoms at different values of the SS parameter. Hence, it is concluded that the SS enhances the VNE of a higher dimensional atomic system such as the 5-level atom. The QE of a higher dimensional atomic system such as the 5-level atom increases with the evolution of time at larger values of the SS parameter, and it also sustains as time progresses. The effect of the SS is more prominent on the 5-level atomic system. When an atom is in motion, in the presence of the SS interacting with the thermal state, the sudden death and birth of QE are observed. The SS environment is favorable for maintaining sudden death and birth of QE, so we can say in the case of a moving N-level atom interacting with the electromagnetic field, the SS supports the QE to maintain and sustain. Hence, non-moving and moving-N-level atomic systems interacting with the electromagnetic field in the presence of the SS are supportive of maintaining and sustaining the QE.