scholarly journals f(R,∇μ1R,…,∇μ1…∇μnR) theories of gravity in Einstein frame: A higher order modified Starobinsky inflation model in the Palatini approach

2019 ◽  
Vol 99 (8) ◽  
Author(s):  
R. R. Cuzinatto ◽  
C. A. M. de Melo ◽  
L. G. Medeiros ◽  
P. J. Pompeia
Keyword(s):  
Higher Order ◽  
Einstein Frame ◽  
Inflation Model ◽  
Theories Of Gravity

scholarly journals Improved gravitational-wave constraints on higher-order curvature theories of gravity

2021 ◽  
Vol 104 (2) ◽  
Author(s):  
Scott E. Perkins ◽  
Remya Nair ◽  
Hector O. Silva ◽  
Nicolás Yunes
Keyword(s):  
Gravitational Wave ◽  
Higher Order ◽  
Theories Of Gravity

scholarly journals FRAME TRANSFORMATIONS OF GRAVITATIONAL THEORIES

2013 ◽  
Vol 28 (12) ◽  
pp. 1350042 ◽  
Author(s):  
XAVIER CALMET ◽  
TING-CHENG YANG
Keyword(s):  
Gravitational Theory ◽  
Space Time ◽  
Einstein Frame ◽  
Jordan Frame ◽  
Quantum Field ◽  
Quantum Fields ◽  
Theoretical Level ◽  
Curved Space ◽  
Inflation Model ◽  
Gravitational Theories

We show how to map gravitational theories formulated in the Jordan frame to the Einstein frame at the quantum field theoretical level considering quantum fields in curved space–time. As an example, we consider gravitational theories in the Jordan frame of the type F(ϕ, R) = f(ϕ)R-V(ϕ) and perform the map to the Einstein frame. Our results can easily be extended to any gravitational theory. We consider the Higgs inflation model as an application of our results.

PERTURBATIONS FROM D-TERM INFLATION

2007 ◽  
Vol 22 (25n28) ◽  
pp. 2035-2038
Author(s):  
OSAMU SETO ◽  
JUN'ICHI YOKOYAMA
Keyword(s):  
Spectral Index ◽  
Cosmic String ◽  
Cosmic Strings ◽  
Unit Length ◽  
Higher Order ◽  
Inflation Model ◽  
Scalar Spectral Index ◽  
String Problem ◽  
Kähler Potential ◽  
Higher Order Corrections

We investigated a simple D-term inflation with taking account of higher order corrections in the Kähler potential. These terms may solve the cosmic string problem in D-term inflation model. The mass per unit length of cosmic strings formed after inflation can be suppressed enough. In addition, the change of the potential slope leads simultaneously a more tilted scalar spectral index ns ≃ 0.96 – 0.97 than that in the model without these corrections.

scholarly journals The gravitational energy-momentum pseudo-tensor of higher-order theories of gravity

2017 ◽  
Vol 529 (5) ◽  
pp. 1600376 ◽  
Author(s):  
Salvatore Capozziello ◽  
Maurizio Capriolo ◽  
Maria Transirico
Keyword(s):  
Higher Order ◽  
Gravitational Energy ◽  
Theories Of Gravity

scholarly journals Scalar–tensor theories of gravity: validity of the cosmic no-hair conjecture

2011 ◽  
Vol 89 (9) ◽  
pp. 937-940
Author(s):  
Sudeshna Mukerji ◽  
Nairwita Mazumder ◽  
Ritabrata Biswas ◽  
Subenoy Chakraborty
Keyword(s):  
Coupling Parameter ◽  
Matter Field ◽  
Einstein Frame ◽  
Energy Conditions ◽  
Jordan Frame ◽  
Scalar Tensor Theory ◽  
Bianchi Models ◽  
Tensor Theory ◽  
Theories Of Gravity ◽  
Theory Of Gravity

This paper deals with the cosmic no-hair conjecture for anisotropic Bianchi models in the scalar–tensor theory of gravity. Herein, we have considered both the Jordan frame and the Einstein frame to describe the scalar–tensor theory of gravity and examine the conjecture. In the Jordan frame, one should restrict both the coupling function of the scalar field and the coupling parameter, in addition to the usual energy conditions for the matter field, to maintain the validity of the cosmic no-hair conjecture, while in the Einstein frame, the restrictions are purely on the energy conditions.

scholarly journals GRAVITATIONAL CHERENKOV RADIATION FROM EXTENDED THEORIES OF GRAVITY

2012 ◽  
Vol 27 (23) ◽  
pp. 1250136 ◽  
Author(s):  
M. DE LAURENTIS ◽  
S. CAPOZZIELLO ◽  
G. BASINI
Keyword(s):  
Cherenkov Radiation ◽  
Higher Order ◽  
Ricci Scalar ◽  
Field Equations ◽  
Massless Spin ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Scalar Invariants ◽  
Extended Theories

We linearize the field equations for higher order theories of gravity that contain scalar invariants other than the Ricci scalar. We find that besides a massless spin-2 field (the standard graviton), the theory contains also spin-0 and spin-2 massive modes with the latter being, in general, ghost modes. The rate at which such particles would emit gravitational Cherenkov radiation is calculated for some interesting physical cases.

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