Challenging the Cosmological Constant

Abstract

We outline a dynamical dark energy scenario whose signatures may be simultaneously tested by astronomical observations and laboratory experiments. The dark energy is a field with slightly sub-gravitational couplings to matter, a logarithmic self-interaction potential with a scale tuned to $\sim 10^{-3}\mathrm{eV}$, as is usual in quintessence models, and an effective mass $m_{\varphi }$ influenced by the environmental energy density. Its forces may be suppressed just below the current bounds by the chameleon-like mimicry, whereby only outer layers of mass distributions, of thickness $1/m_{\varphi }$, give off appreciable long range forces. After inflation and reheating, the field is relativistic, and attains a Planckian expectation value before Hubble friction freezes it. This can make gravity in space slightly stronger than on Earth. During the matter era, interactions with nonrelativistic matter dig a minimum close to the Planck scale. However, due to its sub-gravitational matter couplings the field will linger away from this minimum until the matter energy density dips below $\sim 10^{-12}{\mathrm{eV}}^4$. Then it starts to roll to the minimum, driving a period of cosmic acceleration. Among the signatures of this scenario may be dark energy equation of state $w\ne -1$, stronger gravity in dilute mediums, that may influence BBN and appear as an excess of dark matter, and sub-millimeter corrections to Newton's law, close to the present laboratory limits.

13 pages, 1 .eps figure, added references and comments

References in corpus (7)

• Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale
• Particle Physics Implications of a Recent Test of the Gravitational Inverse Square Law
• Neutrino Dark Energy -- Revisiting the Stability Issue
• Cosmological Evolution of Interacting Dark Energy Models with Mass Varying Neutrinos
• Toward a Unified Description of Dark Energy and Dark Matter from the Abnormally Weighting Energy Hypothesis
• Cosmological Moduli Dynamics
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Cited by in corpus (6)

• Environmental Dependence of Masses and Coupling Constants
• f(R) Gravity and Chameleon Theories
• How (Not) to Palatini
• Supernova Brightening from Chameleon-Photon Mixing
• Unified picture for Dirac neutrinos, dark matter, dark energy and matter-antimatter asymmetry
• The Abnormally Weighting Energy Hypothesis: the Missing Link between Dark Matter and Dark Energy