An introduction to quintessence

Caldwell, Robert R.

doi:10.1590/s0103-97332000000200002

Cited by 47 publications

(21 citation statements)

References 26 publications

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“…All the above mentioned candidates for quintessence have interesting features that make them at some level compatible with the recent obervational facts (see, for example, [6,7,8,9]). Although most of these scenarios have been extensively explored in the recent literature, in the case of a Chaplygin gas-type dark energy, however, only few analysis have focused attention on its cosmological consequences.…”

Section: Introductionmentioning

confidence: 62%

Cosmological consequences of a Chaplygin gas dark energy

2003

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A combination of recent observational results has given rise to what is currently known as the dark energy problem. Although several possible candidates have been extensively discussed in the literature to date the nature of this dark energy component is not well understood at present. In this paper we investigate some cosmological implications of another dark energy candidate: an exotic fluid known as the Chaplygin gas, which is characterized by an equation of state p = −A/ρ, where A is a positive constant. By assuming a flat scenario driven by non-relativistic matter plus a Chaplygin gas dark energy we study the influence of such a component on the statistical properties of gravitational lenses. A comparison between the predicted age of the universe and the latest age estimates of globular clusters is also included and the results briefly discussed. In general, we find that the behavior of this class of models may be interpreted as an intermediary case between the standard and ΛCDM scenarios.

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Section: Introductionmentioning

confidence: 62%

Cosmological consequences of a Chaplygin gas dark energy

2003

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“…Since the consequences of a cosmological constant and a rolling scalar field (usually considered the best candidates) have already been extensively discussed in recent review papers [13], in the present work we emphasize only the main results related to the remaining dark energy candidates.…”

Section: Einsteinmentioning

confidence: 99%

Alternative dark energy models: an overview

Lima¹

2004

Braz. J. Phys.

131

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A large number of recent observational data strongly suggest that we live in a flat, accelerating Universe composed of ∼ 1/3 of matter (baryonic + dark) and ∼ 2/3 of an exotic component with large negative pressure, usually named Dark Energy or Quintessence. The basic set of experiments includes: observations from SNe Ia, CMB anisotropies, large scale structure, X-ray data from galaxy clusters, age estimates of globular clusters and old high redshift galaxies (OHRG's). It is now widely believed that such results provide the remaining piece of information connecting the inflationary flatness prediction (Ω T = 1) with astronomical observations. From a theoretical viewpoint, they have also stimulated the current interest for more general models containing an extra component describing this unknown dark energy, and simultaneously accounting for the present accelerating stage of the Universe. In this review we present a simplified picture of the main results and discuss briefly some difficulties underlying the emerging dark energy paradigm.

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“…Therefore, it is natural to start with cosmology, moving towards the local aspects of gravitation. The presently popular quintessence model features a slowly decaying scalar field associated with a phenomenological potential with a small energy density, of the order of today's value of the Hubble parameter H 0 ∼ 10 −42 GeV [6]. One known criticism to this model is that it is difficult to conciliate such small repulsive new force with the present efforts to solve the hierarchy problem for fundamental interactions [7].…”

Section: History and Trendsmentioning

confidence: 99%

Cosmology and gravitation

Maia¹

2004

Braz. J. Phys.

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This is a brief summary with comments on selected contributions to the Cosmology and Gravitation section at the 24 th Brazilian Meeting on Particle and Fields (ENFPC XXIV), held at Caxambu, from September 30 to October 4, 2003. History and TrendsThe earliest known publication on Einstein' During this period we have grown to approximately 150 researchers in that area, scattered through almost all states of Brazil. The present meeting counted with a total of 84 contributions in CGR alone, including two invited plenary talks, three parallel presentations, 20 short oral communications and 59 poster presentations. Here we present a sampled analysis of these contributions, assembled in just a few categories.There is a noticeable tendency towards cosmology, with 53 contributions, against a only 31 from topics in local gravitation, a clear demonstration of a new trend. This is hardly surprising, considering the present status of cosmology as a highly experimental and interdisciplinary part of physics, which has provided us with a vast and challenging collection of data waiting for explanations.Therefore, it is also no surprise that the two invited plenary talks on CGR were on the main experimental results of observational cosmology, the accelerated expansion and the cosmic background radiation (CMBR). After reviewing the present observational situation, it was pointed out that those results confirm previous measurements of the COBE satellite and more recent balloon and ground-based experiments, but evidenced a deficit of fluctuation power on the largest scales, and also a variation of the spectral index in the primordial perturbation. In his own conclusion, "these measurements have confirmed the parameters of the current 'concordance model' of the Universe, but with some intriguing pointers towards 'new physics' " [4].The second plenary talk by Jerome Martin (Inst. d'Astrophysique de Paris) Inflation and Precision Cosmology, reviewed the inflationary mechanism in cosmology and its consequences to the CMBR anisotropy and formation of large scale structures. The predictions of inflationary theoretical models were compared with the WMAP data, showing an agreement between them. The talk also included an interesting discussion on the trans-Planckian problem of inflation. That is, the fact that all the scales of astrophysical relevance today were, at the beginning of inflation, smaller than the Planck length. Finally, possible observational signatures, in particular in the CMBR anisotropies, leading to topological definitions were also discussed [5].These two talks have set the background for the great majority of the discussions on Cosmology during the meeting. Therefore, it is natural to start with cosmology, moving towards the local aspects of gravitation.

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An introduction to quintessence

Cited by 47 publications

References 26 publications

Cosmological consequences of a Chaplygin gas dark energy

Cosmological consequences of a Chaplygin gas dark energy

Alternative dark energy models: an overview

Cosmology and gravitation

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