Bouncing and accelerating solutions in nonlocal stringy models

Aref’eva, I. Ya.; Joukovskaya, Liudmila; Vernov, S. Yu.

doi:10.1088/1126-6708/2007/07/087

Cited by 84 publications

(72 citation statements)

References 98 publications

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“…where c 7 is another integration constant. From (19), we can notice that for having a TEGR (or GR) background we must have that c 3 = c 2 in the exponential form and c 7 = 0 in the linear form. The Noether vector has the following form…”

Section: A Finding Noether's Symmetriesmentioning

confidence: 99%

Constraining generalized non-local cosmology from Noether symmetries

2017

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We study a generalized non-local theory of gravity which, in specific limits, can become either the curvature non-local or teleparallel non-local theory. Using the Noether symmetry approach, we find that the coupling functions coming from the non-local terms are constrained to be either exponential or linear in form. It is well known that in some non-local theories, a certain kind of exponential non-local couplings is needed in order to achieve a renormalizable theory. In this paper, we explicitly show that this kind of coupling does not need to be introduced by hand, instead, it appears naturally from the symmetries of the Lagrangian in flat Friedmann–Robertson–Walker cosmology. Finally, we find de Sitter and power-law cosmological solutions for different non-local theories. The symmetries for the generalized non-local theory are also found and some cosmological solutions are also achieved using the full theory.

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Section: A Finding Noether's Symmetriesmentioning

confidence: 99%

Constraining generalized non-local cosmology from Noether symmetries

2017

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“…[4,6,19,7,52,38,39]). String field theory and p-adic string theory models have played significant role in motivation and construction of such models.…”

Section: Discussionmentioning

confidence: 99%

On Nonlocal Modified Gravity and Its Cosmological Solutions

Dimitrijevic

Драгович

Stanković

et al. 2016

Springer Proceedings in Mathematics &Amp; Statistics

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During hundred years of General Relativity (GR), many significant gravitational phenomena have been predicted and discovered. General Relativity is still the best theory of gravity. Nevertheless, some (quantum) theoretical and (astrophysical and cosmological) phenomenological difficulties of modern gravity have been motivation to search more general theory of gravity than GR. As a result, many modifications of GR have been considered. One of promising recent investigations is Nonlocal Modified Gravity. In this article we present a brief review of some nonlocal gravity models with their cosmological solutions, in which nonlocality is expressed by an analytic function of the d'Alembert-Beltrami operator . Some new results are also presented.

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“…[36]. Finally, taking into account (80) and (85) one can write the scale factor in the Jordan frame as Fig.…”

Section: Back To Jordan Framementioning

confidence: 99%

“…The model with reciprocal exponential coupling functions can be turned to a Higgs-like one. Scalar models with Higgs potentials inspired by string field theories have been studied recently in [17,35,36]. We also present exact solutions in elliptic functions for this case of the coupling functions.…”

Section: Introductionmentioning

confidence: 99%

Elliptic solutions of generalized Brans–Dicke gravity with a non-universal coupling

2014

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We study a model of the generalized BransDicke gravity presented in both the Jordan and in the Einstein frames, which are conformally related. We show that the scalar field equations in the Einstein frame are reduced to the geodesics equations on the target space of the nonlinear sigma model. The analytical solutions in elliptical functions are obtained when the conformal couplings are given by reciprocal exponential functions. The behavior of the scale factor in the Jordan frame is studied using numerical computations. For certain parameters the solutions can describe an accelerated expansion. We also derive an analytical approximation in exponential functions.

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Bouncing and accelerating solutions in nonlocal stringy models

Cited by 84 publications

References 98 publications

Constraining generalized non-local cosmology from Noether symmetries

Constraining generalized non-local cosmology from Noether symmetries

On Nonlocal Modified Gravity and Its Cosmological Solutions

Elliptic solutions of generalized Brans–Dicke gravity with a non-universal coupling

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