منابع مشابه
Embeddings for 4D Einstein equations with a cosmological constant
There are many ways of embedding a 4D spacetime in a given higher-dimensional manifold while, satisfying the field equations. In this work we extend and generalize a recent paper by Mashhoon and Wesson (Gen. Rel. Gravit. 39, 1403(2007)) by showing different ways of embedding a solution of the 4D Einstein equations, in vacuum with a cosmological constant, in a Ricci-flat, as well as in an anti-d...
متن کاملDuality and the cosmological constant
A dynamical theory is studied in which a scalar field φ in Einstein-Minkowski space is coupled to the four-velocity Nμ of a preferred inertial observer in that space. As a consistent requirement on this coupling we study a principle of duality invariance of the dynamical mass-term of φ at some universal length in the smalldistance regime. In the large-distance regime duality breaking can be int...
متن کاملQuintessence and the cosmological constant
The idea of quintessence originates from an attempt to understand the smallness of the “cosmological constant” or dark energy in terms of the large age of the universe [1]. As a characteristic consequence, the amount of dark energy may be of the same order of magnitude as radiation or dark matter during a long period of the cosmological history, including the present epoch. Today, the inhomogen...
متن کاملWormholes and the Cosmological Constant*
We review Coleman’s wormhole mechanism for the vanishing of the cosmological constant. We show that in a minisuperspace model wormhole-connected universes dominate the path integral. We also provide evidence that the Euclidean path integral over geometries with spherical topology is unstable with respect to formation of infinitely many wormhole-connected 4-spheres. Consistency is restored by su...
متن کاملThe cosmological constant
We discuss issues related with the cosmological constant problem in the light of recent observations which tend to indicate that the expansion of the universe is presently undergoing an acceleration. Models of fundamental physics which address these issues are discussed.
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ژورنال
عنوان ژورنال: Nuclear Physics B
سال: 2000
ISSN: 0550-3213
DOI: 10.1016/s0550-3213(00)00188-7