scholarly journals A NOTE ON DUALITIES IN EINSTEIN'S GRAVITY IN THE PRESENCE OF A NON-MINIMALLY COUPLED SCALAR FIELD

2003 ◽  
Vol 18 (15) ◽  
pp. 1043-1051 ◽  
Author(s):  
L. R. ABRAMO ◽  
L. BRENIG ◽  
E. GUNZIG ◽  
ALBERTO SAA
Keyword(s):  
Scalar Field ◽  
String Theory ◽  
Effective Action ◽  
Low Energy ◽  
Conformal Transformations ◽  
Spacetime Curvature

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.

scholarly journals GRAVITY ON NONCOMMUTATIVE D-BRANES

2003 ◽  
Vol 18 (07) ◽  
pp. 1051-1066 ◽  
Author(s):  
F. ARDALAN ◽  
H. ARFAEI ◽  
M. R. GAROUSI ◽  
A. GHODSI
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Low Energy ◽  
Bosonic String ◽  
First Order ◽  
Energy Scattering ◽  
Bosonic String Theory ◽  
Brane Action

The effective action for the low energy scattering of two gravitons with a D-brane in the presence of a constant antisymmetric B field in bosonic string theory is calculated and the modification to the standard D-brane action to first order in α′ is obtained.

scholarly journals INHOMOGENEOUS SCALAR FIELD SOLUTIONS AND INFLATION

1999 ◽  
Vol 08 (06) ◽  
pp. 705-718 ◽  
Author(s):  
S. E. PEREZ BERGLIAFFA ◽  
K. E. HIBBERD
Keyword(s):  
Scalar Field ◽  
String Theory ◽  
General Framework ◽  
Equations Of Motion ◽  
Energy Condition ◽  
Low Energy ◽  
Strong Energy Condition ◽  
Strong Energy

We present new exact cosmological inhomogeneous solutions for gravity coupled to a scalar field in a general framework specified by the parameter λ. The equations of motion (and consequently the solutions) in this framework correspond to either low-energy string theory or Weyl integrable spacetime according to the sign of λ. We show that different inflationary behaviors are possible, as suggested by the study of the violation of the strong energy condition. Finally, by the analysis of certain curvature scalars we found that some of the solutions may be nonsingular.

scholarly journals Phenomenological Hints from a Class of String Motivated Model Constructions

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Hans Peter Nilles
Keyword(s):  
Dark Matter ◽  
String Theory ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Compact Space ◽  
Effective Action ◽  
Specific Model ◽  
Low Energy ◽  
Grand Unification ◽  
Direct Dark Matter

We use string theory constructions towards the generalisation of the supersymmetric standard model of strong and electroweak interactions. Properties of the models depend crucially on the location of fields in extradimensional compact space. This allows us to extract some generic lessons for the phenomenological properties of the low energy effective action. Within this scheme we present a compelling model based on local grand unification and mirage mediation of supersymmetry breakdown. We analyse the properties of the specific model towards its possible tests at the LHC and the complementarity to direct dark matter searches.

scholarly journals Derive Lovelock gravity from string theory in cosmological background

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Peng Wang ◽  
Houwen Wu ◽  
Haitang Yang ◽  
Shuxuan Ying
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Strong Support ◽  
Effective Theory ◽  
Quadratic Term ◽  
Lovelock Gravity ◽  
Cosmological Background ◽  
Finite Term ◽  
Specific Dimension ◽  
Bonnet Term

Abstract It was proved more than three decades ago, that the first order α′ correction of string effective theory could be written as the Gauss-Bonnet term, which is the quadratic term of Lovelock gravity. In cosmological background, with an appropriate field redefinition, we reorganize the infinite α′ corrections of string effective action into a finite term expression for any specific dimension. This finite term expression matches Lovelock gravity exactly and thus fix the couplings of Lovelock gravity by the coefficients of string effective action. This result thus provides a strong support to string theory.

scholarly journals RECONSTRUCTING A STRING-INSPIRED NONMINIMALLY COUPLED QUINTOM MODEL

2009 ◽  
Vol 18 (08) ◽  
pp. 1291-1301 ◽  
Author(s):  
M. R. SETARE ◽  
J. SADEGHI ◽  
A. R. AMANI
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
String Theory ◽  
Scalar Curvature ◽  
Recent Work ◽  
Nonminimal Coupling ◽  
Tachyon Field ◽  
Dynamical Dark Energy

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.

scholarly journals On the low-energy effective action of N = 2 supersymmetric Yang-Mills theory

1999 ◽  
Vol 537 (1-3) ◽  
pp. 161-183 ◽  
Author(s):  
M. Chaichian ◽  
W.F. Chen ◽  
C. Montonen
Keyword(s):  
Effective Action ◽  
Low Energy ◽  
Yang Mills

scholarly journals Effective action for a quantum scalar field in warped spaces

2015 ◽  
Vol 75 (11) ◽  
Author(s):  
J. M. Hoff da Silva ◽  
E. L. Mendonça ◽  
E. Scatena
Keyword(s):  
Scalar Field ◽  
Effective Action

RENORMALIZATION GROUP EQUATION AND EFFECTIVE ACTION IN STRING THEORY

1989 ◽  
Vol 04 (10) ◽  
pp. 941-951 ◽  
Author(s):  
J. GAITE
Keyword(s):  
Renormalization Group ◽  
String Theory ◽  
Effective Action ◽  
Renormalization Group Equation ◽  
Group Equation ◽  
Generating Functional ◽  
S Matrix

The connection between the renormalization group for the σ-model effective action for the Polyakov string and the S-matrix generating functional for dual amplitudes is studied. A more general approach to the renormalization group equation for string theory is proposed.

scholarly journals FROM p-BRANES TO COSMOLOGY

1999 ◽  
Vol 14 (26) ◽  
pp. 4121-4142 ◽  
Author(s):  
H. LÜ ◽  
S. MUKHERJI ◽  
C. N. POPE
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Dimensional Reduction ◽  
Cosmological Models ◽  
Cosmological Solutions ◽  
M Theory ◽  
The Relationship

We study the relationship between static p-brane solitons and cosmological solutions of string theory or M theory. We discuss two different ways in which extremal p-branes can be generalized to nonextremal ones, and show how wide classes of recently discussed cosmological models can be mapped into nonextremal p-brane solutions of one of these two kinds. We also extend previous discussions of cosmological solutions to include some that make use of cosmological-type terms in the effective action that can arise from the generalized dimensional reduction of string theory or M theory.

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