Detecting dark energy in orbit: The cosmological chameleon
- Service de Physique Theorique, CEA-Saclay, Gif/Yvette cedex, France F-91191 (France)
- Astro-Particle Theory and Cosmology Group, Department of Applied Mathematics, University of Sheffield, Sheffield S3 7RH (United Kingdom)
- DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge, CB3 OWA (United Kingdom)
- Institute for Strings, Cosmology, and Astroparticle Physics, Columbia University, New York, New York 10027 (United States)
We show that the chameleon scalar field can drive the current phase of cosmic acceleration for a large class of scalar potentials that are also consistent with local tests of gravity. These provide explicit realizations of a quintessence model where the quintessence scalar field couples directly to baryons and dark matter with gravitational strength. We analyze the cosmological evolution of the chameleon field and show the existence of an attractor solution with the chameleon following the minimum of its effective potential. For a wide range of initial conditions, spanning many orders of magnitude in initial chameleon energy density, the attractor is reached before nucleosynthesis. Surprisingly, the range of allowed initial conditions leading to a successful cosmology is wider than in normal quintessence. We discuss applications to the cyclic model of the universe and show how the chameleon mechanism weakens some of the constraints on cyclic potentials.
- OSTI ID:
- 20698227
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 70, Issue 12; Other Information: DOI: 10.1103/PhysRevD.70.123518; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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