In this note, it is shown that a nonvanishing spatial curvature can generate primordial matter in the post-inflation era. This matter does not depend on the curvature parameter and is described by a stiff equation of state. It can have the properties of spin matter, consisting of particles with a spin quantum number (spin) s = 1/2. Such a matter can be plausibly identified with quark matter at the early stage of the evolution of the universe.
Categories: gr-qc quant-ph