Theory of superconductivity of gravitation and the dark matter enigma
  In this article, the question of the nature of cold dark matter is approached from a new angle. By invoking the Cauchy problem of relativity it is shown how, under very precise astrophysical conditions, the Einstein general theory of relativity is formally equivalent to the Ginzburg-Landau theory of superconductivity. This fact lead us to suspect that the superconductivity of gravitation ought to be a real physical process occurring in the outskirts of galaxies. It is found that quantum mechanically gravity can achieve a type-II superconductor state characterised by the Gizburg-Landau parameter $\kappa=1.5$, and it is suggested that a probability flux of Cooper pairs (quantum gravitational geons charged with vacuum energy) are directly responsible for the flatness exhibited by the rotation curves in spiral galaxies, as well as the exotic behaviour observed in galactic cluster collisions. If this hypothesis proves correct, the whole phenomenon of dark matter may count, after all, as another triumph for Einstein's theory of gravity. The tension between gravitation and quantum mechanics is explored further by a subtle consideration of the Hamilton-Jacobi theory of the York-time action, providing additional motivation for the above line of reasoning. In particular, Penrose's estimate for the rate of collapse of the wavefunction is recovered, and connected to the instability of Misner space. 
Wenceslao Santiago-Germ\'an
physics.gen-ph gr-qc