Axions as quintessence in string theory

Panda, Sudhakar; Sumitomo, Yoske; Trivedi, Sandip P.

doi:10.1103/physrevd.83.083506

Cited by 113 publications

(138 citation statements)

References 49 publications

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“…The energy density of this model of dark energy can be calculated analytically using the Friedmann equations which has been used in our analysis. At this point, it is worth pointing out that the recently constructed axionic quintessence model in string theory [28] can be described by this parametrization for certain range of parameters.…”

Section: Ss Parametrizationmentioning

confidence: 88%

Post-Planck dark energy constraints

et al. 2015

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Abstract. We constrain plausible dark energy models, parametrized by multiple candidate equation of state, using the recently published Cosmic Microwave Background (CMB) temperature anisotropy data from Planck together with the WMAP-9 low-ℓ polarization data and data from low redshift surveys. To circumvent the limitations of any particular equation of state towards describing all existing dark energy models, we work with three different equation of state covering a broader class of dark energy models and, hence, provide more robust and generic constraints on the dark energy properties. We show that a clear tension exists between dark energy constraints from CMB and non-CMB observations when one allows for dark energy models having both phantom and non-phantom behavior; while CMB is more favorable to phantom models, the low-z data prefers model with behavior close to a Cosmological Constant. Further, we reconstruct the equation of state of dark energy as a function of redshift using the results from combined CMB and non-CMB data and find that Cosmological Constant lies outside the 1σ band for multiple dark energy models allowing phantom behavior. A considerable fine tuning is needed to keep models with strict non-phantom history inside 2σ allowed range. This result might motivate one to construct phantom models of dark energy, which is achievable in the presence of higher derivative operators as in string theory. However, disallowing phantom behavior, based only on strong theoretical prior, leads to both CMB and non-CMB datasets agree on the nature of dark energy, with the mean equation of state being very close to the Cosmological Constant. Finally, to illustrate the impact of additional dark energy parameters on other cosmological parameters, we provide the cosmological parameter constraints for the "Standard Model of Cosmology" including an evolving dark energy component, for the different dark energy models.

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Section: Ss Parametrizationmentioning

confidence: 88%

Post-Planck dark energy constraints

et al. 2015

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“…Applications to cosmic acceleration go under the name K-essence , and were first considered within the context of cosmological inflation [155,156]. There have also been efforts to embed quintessence in some more fundamental theory; for example supersymmetry [157][158][159][160][161] or string theory [162][163][164][165][166][167][168][169][170].…”

Section: (23)mentioning

confidence: 99%

Beyond the cosmological standard model

et al. 2015

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After a decade and a half of research motivated by the accelerating universe, theory and experiment have a reached a certain level of maturity. The development of theoretical models beyond Λ or smooth dark energy, often called modified gravity, has led to broader insights into a path forward, and a host of observational and experimental tests have been developed. In this review we present the current state of the field and describe a framework for anticipating developments in the next decade. We identify the guiding principles for rigorous and consistent modifications of the standard model, and discuss the prospects for empirical tests.We begin by reviewing recent attempts to consistently modify Einstein gravity in the infrared, focusing on the notion that additional degrees of freedom introduced by the modification must "screen" themselves from local tests of gravity. We categorize screening mechanisms into three broad classes: mechanisms which become active in regions of high Newtonian potential, those in which first derivatives of the field become important, and those for which second derivatives of the field are important. Examples of the first class, such as f (R) gravity, employ the familiar chameleon or symmetron mechanisms, whereas examples of the last class are galileon and massive gravity theories, employing the Vainshtein mechanism. In each case, we describe the theories as effective theories and discuss prospects for completion in a more fundamental theory. We describe experimental tests of each class of theories, summarizing laboratory and solar system tests and describing in some detail astrophysical and cosmological tests. Finally, we discuss prospects for future tests which will be sensitive to different signatures of new physics in the gravitational sector.The review is structured so that those parts that are more relevant to theorists vs. observers/experimentalists are clearly indicated, in the hope that this will serve as a useful reference for both audiences, as well as helping those interested in bridging the gap between them.

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“…Quintessence may be realized using axions [232], dilatons [233], in QCD [234], in Higgs potential [235], or in unparticle theories [236].…”

Section: Quintessence Phantom and Quintommentioning

confidence: 99%