Effective action of a scalar field in a curved spacetime with a small inhomogeneity

1993 ◽  
Vol 48 (8) ◽  
pp. 3914-3917 ◽  
Author(s):  
Wung-Hong Huang
2015 ◽  
Vol 75 (11) ◽  
Author(s):  
J. M. Hoff da Silva ◽  
E. L. Mendonça ◽  
E. Scatena

2003 ◽  
Vol 18 (15) ◽  
pp. 1043-1051 ◽  
Author(s):  
L. R. ABRAMO ◽  
L. BRENIG ◽  
E. GUNZIG ◽  
ALBERTO SAA

We show that the action of Einstein's gravity with a scalar field coupled in a generic way to spacetime curvature is invariant under a particular set of conformal transformations. These transformations relate dual theories for which the effective couplings of the theory are scaled uniformly. In the simplest case, this class of dualities reduces to the S-duality of low-energy effective action of string theory.


2002 ◽  
Vol 66 (8) ◽  
Author(s):  
Alejandro Corichi ◽  
Jerónimo Cortez ◽  
Hernando Quevedo

2002 ◽  
Vol 22 (4) ◽  
pp. 757-770 ◽  
Author(s):  
Y. Kiem ◽  
S.-J. Rey ◽  
H.-T. Sato ◽  
J.-T. Yee

1993 ◽  
Vol 02 (04) ◽  
pp. 463-476 ◽  
Author(s):  
SALVATORE CAPOZZIELLO ◽  
RUGGIERO DE RITIS ◽  
PAOLO SCUDELLARO

We perform a systematic analysis of nonminimally coupled cosmologies in (n+1)-dimensional homogeneous and isotropic spacetimes, searching for Nöther’s symmetries and generalizing the results of our previous works. We obtain (i) the absence of symmetries when the spatial curvature constant k is nonzero and n=2, 3, but their existence for all the other n; (ii) the existence of such symmetries for every number of spatial dimensions (except n=1) when k=0. In this latter case, we are able to find a general transformation through which we recover the string-dilaton effective action in (n+1) dimensions and the major peculiarity of string cosmology: the scale factor duality. Furthermore, the symmetry fixes a relation among the coupling F(ϕ), the potential V(ϕ) of the scalar field ϕ, the number of spatial dimensions and the spatial curvature constant. When this is the case, it is possible to find a constant of motion and then get the general solution of the dynamics. Finally, in the framework of the so-called Induced Gravity Theories, we are able to obtain the Newton constant at the present time (t→∞) depending on the number of spatial dimensions and directly related to the constant of motion existing in such a model.


2021 ◽  
Author(s):  
Wen-Xiang Chen

In this article, it mainly discusses that when the scalar field equation presets boundary conditions, the effective action form of Hawking radiation is consistent with the effective action form of superradiation. From this I conclude that Hawking radiation may be a form of superradiation.


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