Nontrival Cosmological Constant in Brane Worlds with Unorthodox Lagrangians

Abstract

In self-tuning brane-world models with extra dimensions, large contributions to the cosmological constant are absorbed into the curvature of extra dimensions and consistent with flat 4d geometry. In models with conventional Lagrangians fine-tuning is needed nevertheless to ensure a finite effective Planck mass. Here, we consider a class of models with non conventional Lagrangian in which known problems can be avoided. Unfortunately these models are found to suffer from tachyonic instabilities. An attempt to cure these instabilities leads to the prediction of a positive cosmological constant, which in turn needs a fine-tuning to be consistent with observations.

17 pages, 1 figure

References in corpus (6)

• Unparticle Physics
• General Axisymmetric Solutions and Self-Tuning in 6D Chiral Gauged Supergravity
• Football Shaped Extra Dimensions and the Absence of Self-Tuning
• Brane singularities and their avoidance
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• Self-tuning of the cosmological constant in brane-worlds with $P(X,\varphi )$
• General self-tuning solutions and no-go theorem
• Ambient cosmology and spacetime singularities
• Tuning the Cosmological Constant, Broken Scale Invariance, Unitarity
• Localizing branes with bifurcating bulks