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Title: K-chameleon and the coincidence problem

Abstract

In this paper we present a hybrid model of k-essence and chameleon, named as k-chameleon. In this model, due to the chameleon mechanism, the directly strong coupling between the k-chameleon field and matters (cold dark matters and baryons) is allowed. In the radiation-dominated epoch, the interaction between the k-chameleon field and background matters can be neglected; the behavior of the k-chameleon therefore is the same as that of the ordinary k-essence. After the onset of matter domination, the strong coupling between the k-chameleon and matters dramatically changes the result of the ordinary k-essence. We find that during the matter-dominated epoch, only two kinds of attractors may exist: one is the familiar K attractor and the other is a completely new, dubbed C attractor. Once the Universe is attracted into the C attractor, the fraction energy densities of the k-chameleon {omega}{sub {phi}} and dust matter {omega}{sub m} are fixed and comparable, and the Universe will undergo a power-law accelerated expansion. One can adjust the model so that the K attractor does not appear. Thus, the k-chameleon model provides a natural solution to the cosmological coincidence problem.

Authors:
;  [1];  [2]
  1. Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)
  2. (China) and CASPER, Department of Physics, Baylor University, Waco, Texas 76798-7316 (United States)
Publication Date:
OSTI Identifier:
20705990
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 71; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevD.71.043504; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ATTRACTORS; BARYONS; BASIC INTERACTIONS; ENERGY DENSITY; MATHEMATICAL SOLUTIONS; NONLUMINOUS MATTER; STRONG-COUPLING MODEL; UNIVERSE

Citation Formats

Wei Hao, Cai Ronggen, and Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080. K-chameleon and the coincidence problem. United States: N. p., 2005. Web. doi:10.1103/PhysRevD.71.043504.
Wei Hao, Cai Ronggen, & Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080. K-chameleon and the coincidence problem. United States. doi:10.1103/PhysRevD.71.043504.
Wei Hao, Cai Ronggen, and Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080. Tue . "K-chameleon and the coincidence problem". United States. doi:10.1103/PhysRevD.71.043504.
@article{osti_20705990,
title = {K-chameleon and the coincidence problem},
author = {Wei Hao and Cai Ronggen and Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080},
abstractNote = {In this paper we present a hybrid model of k-essence and chameleon, named as k-chameleon. In this model, due to the chameleon mechanism, the directly strong coupling between the k-chameleon field and matters (cold dark matters and baryons) is allowed. In the radiation-dominated epoch, the interaction between the k-chameleon field and background matters can be neglected; the behavior of the k-chameleon therefore is the same as that of the ordinary k-essence. After the onset of matter domination, the strong coupling between the k-chameleon and matters dramatically changes the result of the ordinary k-essence. We find that during the matter-dominated epoch, only two kinds of attractors may exist: one is the familiar K attractor and the other is a completely new, dubbed C attractor. Once the Universe is attracted into the C attractor, the fraction energy densities of the k-chameleon {omega}{sub {phi}} and dust matter {omega}{sub m} are fixed and comparable, and the Universe will undergo a power-law accelerated expansion. One can adjust the model so that the K attractor does not appear. Thus, the k-chameleon model provides a natural solution to the cosmological coincidence problem.},
doi = {10.1103/PhysRevD.71.043504},
journal = {Physical Review. D, Particles Fields},
number = 4,
volume = 71,
place = {United States},
year = {Tue Feb 15 00:00:00 EST 2005},
month = {Tue Feb 15 00:00:00 EST 2005}
}