Compactification and signature transition in Kaluza-Klein spinor cosmology

May, 2006
12 pages
Published in:
  • Annals Phys. 321 (2006) 2491-2503
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Abstract: (arXiv)
We study the classical and quantum cosmology of a 4+1-dimensional space-time with a non-zero cosmological constant coupled to a self interacting massive spinor field. We consider a spatially flat Robertson-Walker universe with the usual scale factor R(t)R(t) and an internal scale factor a(t)a(t) associated with the extra dimension. For a free spinor field the resulting equations admit exact solutions, whereas for a self interacting spinor field one should resort to a numerical method for exhibiting their behavior. These solutions give rise to a degenerate metric and exhibit signature transition from a Euclidean to a Lorentzian domain. Such transitions suggest a compactification mechanism for the internal and external scale factors such that aR1a\sim R^{-1} in the Lorentzian region. The corresponding quantum cosmology and the ensuing Wheeler-DeWitt equation have exact solutions in the mini-superspace when the spinor field is free, leading to wavepackets undergoing signature change. The question of stabilization of the extra dimension is also discussed.
Note:
  • 12 pages, 1 figure, to appear in Annals of Physics
  • 04.20.-q
  • 04.60.-m
  • 04.50.+h
  • Kaluza-Klein model
  • dimension: 5
  • cosmological constant
  • spinor: massive
  • signature: transition
  • quantum cosmology
  • Wheeler-DeWitt equation