One-photon wavepacket interacting with two separated atoms in a   one-dimensional waveguide: Influence of virtual photons
  We present a theoretical study of one photon wave-packet scattered by two atoms in one dimensional waveguide. We investigate the role of non rotating wave approximation terms to take into account correctly for the effects of the virtual photons that are exchanged between the atoms. These terms are shown to influence drastically the reflected and the transmitted fields, imposing strict constraints on their temporal envelopes. 
S. Derouault and M. A. Bouchene
quant-ph