Compact stars in massive scalar-tensor theory with extended dilaton potential

2019 ◽  
Author(s):  
Kalin V. Staykov ◽  
Daniela D. Doneva ◽  
Dimitar Popchev ◽  
Stoytcho S. Yazadjiev
Keyword(s):  
Compact Stars ◽  
Scalar Tensor Theory ◽  
Massive Scalar ◽  
Tensor Theory

scholarly journals Orbital and epicyclic frequencies in massive scalar-tensor theory with self-interaction

2019 ◽  
Vol 364 (10) ◽  
Author(s):  
Kalin V. Staykov ◽  
Daniela D. Doneva ◽  
Stoytcho S. Yazadjiev
Keyword(s):  
Scalar Tensor Theory ◽  
Massive Scalar ◽  
Tensor Theory

scholarly journals The dimensional reduction of linearized spin-2 theories invariant under transverse diffeomorphisms

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
D. Dalmazi ◽  
R. R. Lino dos Santos
Keyword(s):  
Dimensional Reduction ◽  
Curvature Vector ◽  
Scalar Tensor Theory ◽  
Massive Scalar ◽  
Tensor Theory ◽  
Tensor Models ◽  
Einstein Spaces ◽  
Non Local ◽  
Pure Tensor ◽  
Local Connection

AbstractHere we perform the Kaluza–Klein dimensional reduction from $$D+1$$ D + 1 to D dimensions of massless Lagrangians described by a symmetric rank-2 tensor and invariant under transverse differmorphisms (TDiff). They include the linearized Einstein–Hilbert theory, linearized unimodular gravity and scalar tensor models. We obtain simple expressions in terms of gauge invariant field combinations and show that unitarity is preserved in all cases. After fixing a gauge, the reduced model becomes a massive scalar tensor theory. We show that the diffeomorphism (Diff) symmetry, instead of TDiff, is a general feature of the massless sector of consistent massive scalar tensor models. We discuss some subtleties when eliminating Stückelberg fields directly at action level as gauge conditions. A non local connection between the massless sector of the scalar tensor theory and the pure tensor TDiff model leads to a parametrization of the non conserved source which naturally separates spin-0 and spin-2 contributions in the pure tensor theory. The case of curved backgrounds is also investigated. If we truncate the non minimal couplings to linear terms in the curvature, vector and scalar constraints require Einstein spaces as in the Diff and WTDiff (Weyl plus Diff) cases. We prove that our linearized massive scalar tensor models admit those curved background extensions.

scholarly journals Models of Compact Stars in the Bimetric Scalar-Tensor Theory of Gravitation

Particles ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 203-211 ◽  
Author(s):  
Levon Grigorian ◽  
Hrant Khachatryan ◽  
Aram Saharian
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Coupling Function ◽  
Compact Stars ◽  
Spherically Symmetric ◽  
Scalar Tensor Theory ◽  
Metric Tensor ◽  
Tensor Theory ◽  
Theory Of Gravitation ◽  
The Masses

We investigate static spherically-symmetric configurations of gravitating masses in the bimetric scalar-tensor theory of gravitation. In the gravitational sector, the theory contains the metric tensor, a scalar field and a background metric as an absolute variable of the theory. The analysis is presented for the simplest version of the theory with a constant coupling function and a zero cosmological function. We show that, depending on the value of the theory parameter, the masses for superdense compact configurations can be essentially larger compared to the configurations in general relativity.

scholarly journals Field Independent Cosmic Evolution

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Nayem Sk ◽  
Abhik Kumar Sanyal
Keyword(s):  
Higher Order ◽  
Noether Symmetry ◽  
Scalar Tensor Theory ◽  
Anisotropic Model ◽  
Tachyonic Field ◽  
Tensor Theory ◽  
Cosmic Evolution ◽  
Field Independent ◽  
Conserved Current ◽  
Theory Of Gravity

It has been shown earlier that Noether symmetry does not admit a form of corresponding to an action in which is coupled to scalar-tensor theory of gravity or even for pure theory of gravity taking anisotropic model into account. Here, we prove that theory of gravity does not admit Noether symmetry even if it is coupled to tachyonic field and considering a gauge in addition. To handle such a theory, a general conserved current has been constructed under a condition which decouples higher-order curvature part from the field part. This condition, in principle, solves for the scale-factor independently. Thus, cosmological evolution remains independent of the form of the chosen field, whether it is a scalar or a tachyon.

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