In this paper, we develop the notion of the marginal and density atomic Wehrl entropies for a two-level atom interacting with the single mode field, i.e. the Jaynes–Cummings model. For this system we show that there are relationships between these quantities and both the information entropies and the von Neumann entropy.
The linear entropy, the von Neumann entropy and the atomic Wehrl entropy are frequently used to quantify entanglement in the quantum systems. These relations provide typical information on the entanglement in the Jaynes-Cummings model (JCM). In this Letter, we explain the origin of this analytically and derive a closed form for the atomic Wehrl entropy. Moreover, we show that it is more convenient to use the Bloch sphere radius for quantifying entanglement in the JCM instead of these entropic relations.
The concept of the classical-like Wehrl entropy is shown to be a very sensitive and informative measure describing the time evolution of a quantum system. Its applications to the Jaynes-Cummings model reveal relevant aspects of the field dynamics. The Wehrl entropy provides a compact one-parameter description giving, among other things, a clear signature for the splitting of the Q function. It gives also a clear indication of the phase randomization of the coherent electromagnetic field states during the interaction with a two-level atom.
Abstract In this paper we have studied the dynamical evolution of Shannon information entropies in position and momentum spaces for two classes of (nonstationary) atom-field entangled states, which are obtained via the Jaynes–Cummings model and its generalization. We have focused on the interaction between two- and Ξ-type three-level atoms with the single-mode quantized field. The three-dimensional plots of entropy densities in position and momentum spaces are presented versus corresponding coordinates and time, numerically. It is observed that for particular values of the parameters of the systems, the entropy squeezing in position space occurs. Finally, we have shown that the well-known BBM (Beckner, Bialynicki-Birola and Mycielsky) inequality, which is a stronger statement of the Heisenberg uncertainty relation, is properly satisfied.