DYNAMICAL PROPERTIES OF A CLASSICAL-LIKE ENTROPY IN THE JAYNES-CUMMINGS MODEL

The concept of the classical-like Wehrl entropy is shown to be a very sensitive and informative measure describing the time evolution of a q uantum system. Its applications to the Jaynes-Cummings model reveal re levant aspects of the field dynamics. The Wehrl entropy provides a com pact one-parameter description giving, among other things, a clear sig nature for the splitting of the Q function. It gives also a clear indi cation of the phase randomization of the coherent electromagnetic fiel d states during the interaction with a two-level atom.