The Ghost (Phantom) Universe: A Model in which the Universe is Flat, Quantum Ghost Matter and Vacuum Dominated and Accelerating
We propose a modification of the Standard Hot Big Bang Cosmology (SHBBC), in which the Universe is flat, quantum matter dominated, and accelerating. The total energy density of the Universe is taken to be the sum of two terms: the quantum contributions from vacuum and plus an additional quantum (ghost) term (with negative pressure) which is responsible of the dominant driver of expansion at a late epoch of the Universe. When the new term dominates, the scalar factor varies as R ∝ t 4 3 (Accelerating Flat Ghost Universe). The quantum energy density required to close the Ghost Universe is found to be much smaller than in SHBBC, so that quantum matter can be sufficient to provide a flat geometry. Quantum matter particles interactions are interpreted as a quantum fifth force and it is found to vary as F (r) ∝ r 1 2 . The Universe we live in is dynamic, in other word the space-time is expanding. It is it full of all kinds of exotic objects. Edwin Hubble discovered this in the 1920s. When Hubble looked at galaxies outside of our own, he saw that they were all racing away from us. That might suggest there was an initial explosion that we sat at the center of. But it would be unreasonable to assume that our galaxy is the center of the universe! So, instead, we deduce that the fabric of space-time, the sheet in which all these galaxies sit, is itself expanding. What causes the universe to expand? That’s actually two different interesting questions.