We calculate the Casimir-Polder intermolecular potential using an effective
Hamiltonian recently introduced. We show that the potential can be expressed in
terms of the dynamical polarizabilities of the two atoms and the equal-time
spatial correlation of the electric field in the vacuum state. This gives
support to an interesting physical model recently proposed in the literature,
where the potential is obtained from the classical interaction between the
instantaneous atomic dipoles induced and correlated by the vacuum fluctuations.
Also, the results obtained suggest a more general validity of this intuitive
model, for example when external boundaries or thermal fields are present.Comment: 7 page