Abstract
We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero) and the coincidence problem (why Λ is comparable to the matter density now).
Highlights
The cosmological constant problem is one of the most challenging problems in theoretical physics today
In this paper we present a new approach to the cosmological constant problem, based on the chameleon scalar idea
In this paper we have given an alternative to a simple cosmological constant based on chameleon scalars
Summary
The cosmological constant problem is one of the most challenging problems in theoretical physics today. The potential has a minimum which we set exactly at V = 0 Within this model, we will find that the value for the scalar field potential is approximately constant near concentrations of matter (with density greater than a minimum density), and the fact that the value of this potential is so small and comparable with the density of matter arises from the condition of minimization of the effective potential (1.1).. We will find that the value for the scalar field potential is approximately constant near concentrations of matter (with density greater than a minimum density), and the fact that the value of this potential is so small and comparable with the density of matter arises from the condition of minimization of the effective potential (1.1).1 In this way we translate both the issue of the smallness of the cosmological constant and the coincidence problem (ρ ∼ ρDM) into just choosing the shape of the potential, which we argue is quite natural.
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