Abstract
We assume the space-time foam picture in which the vacuum is filled with a gas of virtual wormholes. It is shown that virtual wormholes form a finite (of the Planckian order) value of the energy density of zero-point fluctuations. However such a huge value is compensated by the contribution of virtual wormholes to the mean curvature and the observed value of the cosmological constant is close to zero. A nonvanishing value appears due to the polarization of vacuum in external classical fields. In the early Universe some virtual wormholes may form actual ones. We show that in the case of actual wormholes vacuum polarization effects are negligible while their contribution to the mean curvature is apt to form the observed dark energy phenomenon. Using the contribution of wormholes to dark matter and dark energy we find estimates for characteristic parameters of the gas of wormholes.
Highlights
As is well known modern astrophysics faces two key problems
We show that virtual wormholes form a finite value of the energy density of zero-point fluctuations
We show that the presence of the gas of virtual wormholes can be described by the topological bias exactly as it happens in the presence of actual wormholes [7, 9]
Summary
As is well known modern astrophysics (and, even more generally, theoretical physics) faces two key problems. The principle difference is that a virtual wormhole exists only for a very small period of time and at very small scales and does not necessarily obey to the Einstein equations It represents tunnelling event and the averaged null energy condition (ANEC) cannot forbid the origin of such an object. We show that virtual wormholes form a finite (of the Planckian order) value of the energy density of zero-point fluctuations Such a huge value is compensated by the contribution of virtual wormholes to the mean curvature and the observed value of the cosmological constant should be close to zero. We demonstrate that the cosmological constant is determined by the contribution of the energy density of zero-point fluctuations and by the contribution of virtual wormholes to the mean curvature.
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