Letter to the Editor
Lyra cosmology in D=n+4 dimensions: the interesting cases of n ≥ 6 and n ≤ 104
Rami Ahmad El-Nabulsi
; Department of Nuclear and Energy Engineering, Cheju National University, Ara-dong 1, Jeju 690-756, South Korea
Abstract
Exact solutions of the Einstein’s field equations in Lyra geometry in D = 4 + n dimensional spacetime with time-increasing G and decaying cosmic fluid and density are obtained and discussed in some details. We suggest the phenomenological dissipative law β 2 ∝ H/t for the square of the non-zero component of the displacement vector field φA. H is the Hubble parameter in the extra-dimensional spacetime metric. It has been observed that the cases n ≥ 6 are within the observational limit, the four-dimensional spacetime is in the stage of accelerated expansion, while the extra-dimensions are contracting in time.
Keywords
higher-dimensional cosmology; gravitational constant; Lyra geometry; effective pressure
Hrčak ID:
304576
URI
Publication date:
3.5.2009.
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