Primordial seeds of supermassive black holes
  Supermassive black holes exist in the centers of galaxies, including Milky
Way, but there is no compelling theory of their formation. Furthermore,
observations of quasars imply that supermassive black holes have already
existed at some very high redshifts, suggesting the possibility of their
primordial origin. In a class of well-motivated models, inflationary epoch
could include two or more periods of inflation dominated by different scalar
fields. The transition between such periods of inflation could enhance the
spectrum of density perturbations on some specific scale, which could lead to
formation of primordial black holes with a very narrow range of masses of the
order of 10^5 solar masses. These primordial black holes could have provided
the requisite seeds for the observed population of supermassive black holes.
