B Vakili and H R Sepangi JCAP09(2005)008 doi:10.1088/1475-7516/2005/09/008
B Vakili1 and H R Sepangi1,2
Show affiliationsWe study the classical and quantum evolution of a universe in which the matter source is a massive Dirac spinor field and the universe is described by a Bianchi type I metric. We focus attention on those classical solutions that admit a degenerate metric in which the scale factors have smooth behaviour in the transition from a Euclidean to a Lorentzian domain and show that this transition happens when the cosmological constant, Λ, is negative. The resulting quantum cosmology and the corresponding Wheeler–DeWitt equation are also studied and closed form expressions for the wavefunctions of the universe are presented. We have shown that there is a close relationship between the quantum states and signature changing classical solutions, suggesting a mechanism for creation of a Lorentzian universe from a Euclidean region by a continuous change of signature. The quantum solutions also represent a quantization rule for the mass of the spinor field.
11.27.+d Extended classical solutions; cosmic strings, domain walls, texture
Issue 09 (September 2005)
Received 23 July 2005, accepted for publication 29 August 2005
Published 8 September 2005
B Vakili and H R Sepangi JCAP09(2005)008
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