COMPLETE DETERMINATION OF ATOMIC STATES BY PHOTON MOMENTUM-TRANSFER

In this paper we present a theory which shows that the optical force o n atoms due to spontaneous processes depends upon the quantum state of the atom at the time it begins interacting with the optical field. Th e momentum is treated as a classical variable and the theory used to m odel the interaction between the atom and radiation is based on a quan tum electrodynamic technique. The formalism developed is quite general and, in principle, can be applied to the determination of initial ato mic states prepared by a variety of mechanisms. An example of an appli cation of the spontaneous force is presented which shows how it is pos sible to use the momentum absorbed by an atom from a coherent light fi eld to determine the density matrix of the atomic state created by a c ollision process. For completeness, the derivation of a stimulated for ce model is included where it is shown that the resulting force on ato ms also depends on their initial state.