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Physics 2000
Field theory model giving rise to "quintessential inflation" without the cosmological constant and other fine tuning problemsDOI: 10.1103/PhysRevD.63.025022 Abstract: A field theory is developed based on the idea that the effective action of yet unknown fundamental theory, at energy scale below M_{p} has the form of expansion in two measures: S=\intd^{4}x[\Phi L_{1}+\sqrt{-g}L_{2}] where the new measure \Phi is defined using the third-rank antisymmetric tensor. In the new variables (Einstein frame) all equations of motion take canonical GR form and therefore models are free of the well-known "defects" that distinguish the Brans-Dicke type theories from GR. All novelty is revealed only in an unusual structure of the effective potential U(\phi) and interactions which turns over intuitive ideas based on our experience in field theory. E.g. the greater \Lambda we admit in L_{2}, the smaller U(\phi) will be in the Einstein picture. Field theory models are suggested with explicitly broken global continuos symmetry which in the Einstein frame has the form \phi\to\phi+const. The symmetry restoration occurs as \phi\to\infty. A few models are presented where U is produced with the following shape: for \phi<-M_{p}, U has the form typical for inflation model, e. g. U=\lambda\phi^4 with \lambda\sim 10^{-14}; for\phi>-M_{p}, U has mainly exponential form U\sim e^{-a\phi/M_{p}} with variable a: a=14 for -M_{p}<\phi
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