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Results in Physics

Quantum coherence and phase-space nonclassicality in k -photon thermal-noisy nonlinear JCM with atomic motion

Shima Manzari-Tavakoli, Hamid Reza Baghshahi, Mohammad Javad Faghihi

Published May 9, 2025• 1 citation
Publisher

Abstract

In this paper, we study the quantum interaction between a moving two-level atom and a single-mode quantized field in an optical cavity with degenerate multi-photon transition, in the presence of intensity-dependent coupling and thermal effect. We introduce the appropriate Hamiltonian of the system, and we adopt the initial condition of subsystems, in which the atom is prepared in an arbitrary superposition of ground and excited states, and the field is considered in a thermal state. Consequently, we determine the density matrix of the entire system at any given time. We further assess some of the most important quantum properties, such as quantum coherence, sub-Poissonian statistics, and phase-space nonclassicality by means of negativity of the Wigner quasiprobability distribution function. We then investigate the impact of intensity-dependent nonlinearity, thermal noise, atomic motion, and multi-photon transition on these quantum properties. The numerical results show that the nonclassicality criteria can be significantly influenced and controlled by the effects discussed above. Interestingly, increasing the mean thermal photon number, which highlights the thermal effect, can, in some cases, enhance the nonclassicality features of the system.

DOI
10.1016/j.rinp.2025.108279

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The interaction between a ♢\diamondsuit♢-type four-level atom and a single-mode field in the presence of Kerr medium with intensity-dependent coupling involving multi-photon processes has been studied. Using the generalized (nonlinear) Jaynes-Cummings model, the exact analytical solution of the wave function for the considered system under particular condition, has been obtained when the atom is initially excited to the topmost level and the field is in a coherent state. Some physical properties of the atom-field entangled state such as linear entropy showing the entanglement degree, Mandel parameter, mean photon number and normal squeezing of the resultant state have been calculated. The effects of Kerr medium, detuning and the intensity-dependent coupling on the temporal behavior of the latter mentioned nonclassical properties have been investigated. It is shown that by appropriately choosing the evolved parameters in the interaction process, each of the above nonclassicality features, which are of special interest in quantum optics as well as quantum information processing, can be revealed.
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