On the Generation of X-Ray Photon Pairs: A Verification of the Unruh   Effect?
  We investigate the production of entangled X-ray photons by incoherent double Compton scattering (IDCS) which seems to be an interesting alternative to coherent double Compton scattering used in earlier work. Very recently it has been proposed to use the Unruh effect as a source for photon pairs (R.Sch\"utzhold et al.,Phys.Rev.Lett. 100, 091301 (2008)). We will discuss this mechanism in comparison with inverse IDCS. 
Friedhelm Bell