Volume 554, June 2013
|Number of page(s)||6|
|Section||Cosmology (including clusters of galaxies)|
|Published online||04 June 2013|
Can dark energy emerge from quantum effects in a compact extra dimension?
1 Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, 31062 Toulouse, France
2 Université Pierre et Marie Curie, UPMC, ENS, Laboratoire Kastler Brossel, 75252 Paris Cedex 05, France
3 CNRS, UMR 8552, 75252 Paris, France
4 Université de Toulouse, UPS-OMP, IRAP, 31400 Toulouse, France
5 CNRS, IRAP, 14, avenue Edouard Belin, 31400 Toulouse, France
Received: 8 January 2013
Accepted: 17 April 2013
The origin of the accelerated expansion of the universe is a major problem in both modern cosmology and theoretical physics. In quantum field theory, simple estimations of the vacuum contribution to the density energy of the Universe are known to lead to catastrophically high values compared to observations. A gravitational Casimir effect from an additional compact dimension of space is known to lead to an effective cosmological constant. Nevertheless, such a contribution by itself is usually not regarded as a plausible source for accelerating the expansion, given the constraints on such scenarios. Here, we propose that the Casimir vacuum contribution of the gravitational field actually provides a low positive value to the density energy of the universe. The key new ingredient is to assume that only modes with shorter wavelengths than the Hubble radius contribute to the vacuum energy. Such a contribution gives a positive energy density, has a naturally Lorentz invariant equation of state in the usual 4D spacetime, and can thus be interpreted as a cosmological constant. Its value agrees with observations for a radius of a fifth extra dimension given by 35 μm. The implied modification of the gravitational inverse square law is close but below existing limits from experiments testing gravity at short range.
Key words: gravitation / dark energy / cosmology: theory
© ESO, 2013
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.