Quantum channel for light based on integrals of motion
  A method based on integrals of motion for collective processes has been introduced to achieve physical schemes in which one of the systems is insensitive to interaction. Decoherence-free quantum channels that allow sending any state of light, particulary the Fock states, through an absorbing medium are considered as an example. 
V.N. Gorbachev, A.I. Trubilko