## Abstract

Realizations of scale invariance are studied in the context of a gravitational theory where the action (in the first-order formalism) is of the form S = ∫L_{1}Φd^{4}cursive Greek chi + ∫L_{2}√-gd^{4}cursive Greek chi where Φ is a density built out of degrees of freedom, the "measure fields" independent of g_{μν} and matter fields appearing in L_{1}, L_{2}. If L_{1} contains the curvature, scalar potential V(φ) and kinetic term for φ, L_{2} another potential for φ, U(φ), then the true vacuum state has zero energy density, when theory is analyzed in the conformal Einstein frame (CEF), where the equations assume the Einstein form. Global scale invariance is realized when V(φ) = f_{1}e^{αφ} and U(φ) = f_{2}e^{2αφ}. In the CEF the scalar field potential energy V_{eff}(φ) has, in addition to a minimum at zero, a flat region for αφ → ∞, with nonzero vacuum energy, which is suitable for either a new inflationary scenario for the early universe or for a slowly rolling decaying Λ-scenario for the late universe, where the smallness of the vacuum energy can be understood as a kind of seesaw mechanism.

Original language | English |
---|---|

Pages (from-to) | 1043-1052 |

Number of pages | 10 |

Journal | Modern Physics Letters A |

Volume | 14 |

Issue number | 16 |

DOIs | |

State | Published - 30 May 1999 |

## ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Astronomy and Astrophysics
- Physics and Astronomy (all)