Interaction between incoherent light beams propagating in excited atomic   hydrogen; applications in astrophysics
  While it is generally assumed that several light beams propagate independently in a refracting medium, the exception of laser beams may be extended to usual time-incoherent light provided that conditions of space-coherence are fulfilled. Very few molecules have convenient properties, the simplest one being atomic hydrogen in 2S and 2P states (called H* here).   The interaction increases the entropy of a set of beams without a permanent excitation of H*, a loss of energy by a beam having a high Planck's temperature producing a decrease of its frequency, and the thermal radiation getting energy.   Atomic hydrogen in its ground state is pumped to H* by Lyman alpha absorptions, producing a redshift of the light. The combination of the Lyman absorptions and the redshifts they produce, induce oscillations which generate a spectrum in which the lines deduce from each other by relative frequency shifts which are products of an integer by a constant z_b=0.062.   These purely physical results may be applied in astrophysics, searching where H* may appear. In particular, the computed spectra of the accreting neutron stars, remarkably identical to the spectra of the quasars, may explain that these stars seem never observed. The too high frequencies of the radio signals from the Pioneer probes may result from a transfer of energy from the solar light allowed by a cooling of the solar wind able to produce H*. A similar transfer to the CMB may explain its anisotropy bound to the ecliptic. 
Jacques Moret-Bailly