Abstract
This letter deals with a number of criteria for separability/entanglement in the Jaynes-Cummings model of the interaction between a two-level atom and a single mode of photon radiation. A condition for the state separability of mixed states based on the difference in the distances between the photon distributions initially and at an arbitrary time is proposed. It is compared with two other measures of degree of separability, namely the radius of the Bloch sphere and the negative eigenvalue of the matrix derived from the reduction criterion. The case where the radiation is initially in a squeezed state is treated with details.