Stabilization of extra dimensions in higher-dimensional cosmological models


Stabilization of extra dimensions in higher-dimensional cosmological models

Günther, U.

We present an overview over research on higher-dimensional cosmological models carried out from 1997 till 2004. The basic starting point is the problem of stabilizing the sizes of the extra-dimensional factor spaces so that they are kept unobservable at low energies --- as indicated by current data from high-energy collider experiments and astrophysical observations. This problem is well known as the moduli stabilization problem in string theory and M-theory. Stabilizing the scale factors of the extra-dimensional factor spaces by some effective potentials (which are naturally induced via dimensional reduction of the higher-dimensional setups) fixes only the average sizes (moduli) but still allows for small (quantum) fluctuations around the minimum position (radion fluctuations). Once these fluctuations will depend on the coordinates of our external (uncompactified) space they will act as multicomponent scalar fields. Due to their Planck-scale-suppressed coupling to usual standard matter they may be considered as possible candidates for dark matter or UHECR (ultra-high energy cosmic rays).
In the talk, we comment on various dimensional reduction schemes, large extra dimensions (ADD-setups) as well as on orbifold compactification schemes of Randall-Sundrum type. We provide a brief summary about the obtained results published during the 8 years of active research in this field --- including discussions of effective static and dynamic perfect fluid scenarios, relations to reheating, transitions from radiation dominance to matter dominance, quintessence, UHECR, reaction channels with standard matter and possible creation of moduli excitations in ultra-strong background magnetic fields of magnetars. Finally, we give a brief overview about results on higher-dimensional f(R) theories as they are used in 4D as possible explanation for dynamically induced dark energy.

Keywords: string theory; M-theory; phenomenology; cosmology; extra dimensions; moduli stabilization; radion fluctuations; perfect fluids; UHECR; magnetars; f(R) gravity; dark matter; dark energy

  • Invited lecture (Conferences)
    Institutsseminar, 10.12.2008, Jena, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-12054
Publ.-Id: 12054