PRODUCTION OF DIRAC PARTICLES DUE TO RICCION COUPLING

It has been noted that at high energy the Ricci scalar is manifested i n two different ways, as a matter field as well as a geometrical field (which is its usual nature even at low energy). Here, using the mater ial aspect of the Ricci scalar, its interaction with Dirac spinors is considered in four-dimensional curved spacetime. We find that a large number of fermion-antifermion pairs can be produced by the exponential expansion of the early universe.