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キーワード:
General Relativity and Quantum Cosmology, gr-qc,High Energy Physics - Theory, hep-th
要旨:
A spacetime condensation phenomenon underlies the emergence of a macroscopic
universe in causal dynamical triangulations, where the time extension of the
condensate is strictly smaller than the total time. It has been known for some
time that the volumes of spatial slices in the bulk of the macroscopic universe
follow a time evolution which resembles that of a sphere, and their effective
dynamics is well described by a minisuperspace reduction of the general
relativistic action. More recently, it has been suggested that the same
minusuperspace model can also provide an understanding of the condensation
phenomenon itself, thus explaining the presence of an extended droplet of
spacetime connected to a stalk of minimal spatial extension. We show here that
a minisuperspace model based on the general relativistic action fails in that
respect for the (2+1)-dimensional case, while a successful condensation is
obtained from a minisuperspace model of Horava-Lifshitz gravity.
