@article{294,
  abstract     = {We developed a method to calculate two-photon processes in quantum mechanics that replaces the infinite summation over the intermediate states by a perturbation expansion. This latter consists of a series of commutators that involve position, momentum, and Hamiltonian quantum operators. We analyzed several single- and many-particle cases for which a closed-form solution to the perturbation expansion exists, as well as more complicated cases for which a solution is found by convergence. Throughout the article, Rayleigh and Raman scattering are taken as examples of two-photon processes. The present method provides a clear distinction between the Thomson scattering, regarded as classical scattering, and quantum contributions. Such a distinction lets us derive general results concerning light scattering. Finally, possible extensions to the developed formalism are discussed.},
  author       = {Fratini, Filippo and Safari, Laleh and Amaro, Pedro and Santos, José},
  journal      = {Physical Review A - Atomic, Molecular, and Optical Physics},
  number       = {4},
  publisher    = {American Physical Society},
  title        = {{Two-photon processes based on quantum commutators}},
  doi          = {10.1103/PhysRevA.97.043842},
  volume       = {97},
  year         = {2018},
}