scholarly journals Natural inflation with a nonminimal coupling to gravity

2021 ◽  
Vol 2021 (03) ◽  
pp. 059
Author(s):  
Yakefu Reyimuaji ◽  
Xinyi Zhang
Keyword(s):  
2019 ◽  
Vol 790 ◽  
pp. 354-360 ◽  
Author(s):  
R. Casana ◽  
J.S. Rodrigues ◽  
F.E.P. dos Santos

2009 ◽  
Vol 18 (08) ◽  
pp. 1291-1301 ◽  
Author(s):  
M. R. SETARE ◽  
J. SADEGHI ◽  
A. R. AMANI

Motivated by the recent work of Zhang and Chen,1we generalize their work to the nonminimally coupled case. We consider a quintom model of dark energy with a single scalar field T given by a Lagrangian inspired by a tachyonic Lagrangian in string theory. We consider nonminimal coupling of the tachyon field to the scalar curvature, and then we reconstruct this model in the light of three forms of parametrization for dynamical dark energy.


2013 ◽  
Vol 22 (12) ◽  
pp. 1342014 ◽  
Author(s):  
XAVIER CALMET

In this paper, we discuss an effective theory for quantum gravity and discuss the bounds on the parameters of this effective action. In particular, we show that measurement in pulsars binary systems are unlikely to improve the bounds on the coefficients of the R2 and RμνRμν terms obtained from probes of Newton's potential performed on Earth. Furthermore, we argue that if the coefficients of these terms are induced by quantum gravity, they should be at most of order unity since R2 and RμνRμν are dimension four operators. The same applies to the nonminimal coupling of the Higgs boson to the Ricci scalar.


2011 ◽  
Vol 20 (13) ◽  
pp. 2543-2558 ◽  
Author(s):  
SAMUEL LEPE ◽  
JAVIER LORCA ◽  
FRANCISCO PEÑA ◽  
YERKO VÁSQUEZ

From a variational action with nonminimal coupling with a scalar field and classical scalar and fermionic interaction, cosmological field equations can be obtained. Imposing a Friedmann–Lemaître–Robertson–Walker (FLRW) metric, the equations lead directly to a cosmological model consisting of two interacting fluids, where the scalar field fluid is interpreted as dark energy and the fermionic field fluid is interpreted as dark matter. Several cases were studied analytically and numerically. An important feature of the non-minimal coupling is that it allows crossing the barrier from a quintessence to phantom behavior. The insensitivity of the solutions to one of the parameters of the model permits it to find an almost analytical solution for the cosmological constant type of universe.


2018 ◽  
Vol 27 (11) ◽  
pp. 1843009 ◽  
Author(s):  
Carlos A. R. Herdeiro ◽  
Eugen Radu

We obtain spinning boson star solutions and hairy black holes with synchronized hair in the Einstein–Klein–Gordon model, wherein the scalar field is massive, complex and with a nonminimal coupling to the Ricci scalar. The existence of these hairy black holes in this model provides yet another manifestation of the universality of the synchronization mechanism to endow spinning black holes with hair. We study the variation of the physical properties of the boson stars and hairy black holes with the coupling parameter between the scalar field and the curvature, showing that they are, qualitatively, identical to those in the minimally coupled case. By discussing the conformal transformation to the Einstein frame, we argue that the solutions herein provide new rotating boson star and hairy black hole solutions in the minimally coupled theory, with a particular potential, and that no spherically symmetric hairy black hole solutions exist in the nonminimally coupled theory, under a condition of conformal regularity.


2014 ◽  
Vol 29 (22) ◽  
pp. 1450112 ◽  
Author(s):  
R. Bufalo

Inspired in discussions presented lately regarding Lorentz-violating interaction terms in B. Charneski, M. Gomes, R. V. Maluf and A. J. da Silva, Phys. Rev. D86, 045003 (2012); R. Casana, M. M. Ferreira Jr., R. V. Maluf and F. E. P. dos Santos, Phys. Lett. B726, 815 (2013); R. Casana, M. M. Ferreira Jr., E. Passos, F. E. P. dos Santos and E. O. Silva, Phys. Rev. D87, 047701 (2013), we propose here a slightly different version for the coupling term. We will consider a modified quantum electrodynamics with violation of Lorentz symmetry defined in a (2+1)-dimensional space–time. We define the Lagrangian density with a Lorentz-violating interaction, where the space–time dimensionality is explicitly taken into account in its definition. The work encompasses an analysis of this model at both zero and finite-temperature, where very interesting features are known to occur due to the space–time dimensionality. With that in mind, we expect that the space–time dimensionality may provide new insights about the radiative generation of higher-derivative terms into the action, implying in a new Lorentz-violating electrodynamics, as well the nonminimal coupling may provide interesting implications on the thermodynamical quantities.


2019 ◽  
Vol 945 ◽  
pp. 114677 ◽  
Author(s):  
V.E. Mouchrek-Santos ◽  
Manoel M. Ferreira ◽  
Carlisson Miller
Keyword(s):  

1993 ◽  
Vol 10 (8) ◽  
pp. 507-509 ◽  
Author(s):  
Wenfu Wang ◽  
Caide Tao
Keyword(s):  

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