Can dark matter be polaritons? There is a new theory of dark matter were dark matter is a Bose Einstein condensate (BEC). Dark matter acts as if it was a soliton.
http://arxiv.org/pdf/0805.3827.pdf *BEC dark matter can explain collisions of galaxy clusters* <snip> we have reinterpreted cold dark matter as a Bose-Einstein condensate". So, "the ultra-light bosons forming the condensate share the same quantum wave function, so disturbance patterns are formed on astronomic scales in the form of large-scale waves". Read more at: http://phys.org/news/2014-07-reinterpreting-dark.html#jCp <End snip> Light and electrons could be entangled on a large scale to form a polariton BEC soliton much as they do in LENR. Polaritons are almost massless forming bosons. The charge of the polaritons could be delocalized to make polariton dark matter non interacting. In NiH reactor will be a great test bed to explore the polariton BEC in understanding dark matter cosmology more deeply.

