Quantum-bias cosmology: Acceleration from holographic information capacity

摘要

I show that a generic quantum phenomenon can drive cosmic acceleration without the need for dark energy or modified gravity. When treating the universe as a quantum system, one typically focuses on the scale factor [of a Friedmann-Robertson-Walker (FRW) spacetime] and ignores many other degrees of freedom. However, the information capacity of the discarded variables will inevitably change as the universe expands, generating quantum bias (QB) in the Friedmann equations. If information could be stored in each Planck volume independently, this effect would give rise to a constant acceleration 10~(120) times larger than that observed, reproducing the usual cosmological constant problem. However, once information capacity is quantified according to the holographic principle, cosmic acceleration is far smaller and depends on the past behavior of the scale factor. I calculate this holographic quantum bias, derive the semiclassical Friedmann equations, and obtain their general solution for a spatially flat universe containing matter and radiation. Comparing these QB-CDM solutions (which include standard cold dark matter) to those of ΛCDM, the new theory is shown to be falsifiable, but nonetheless consistent with current observations. In general, realistic QB cosmologies undergo phantom acceleration (w_(eff) < ?1) at late times, predicting a big rip in the distant future.