The Effect of Intrinsic Spin on Neutron Stars in the Einstein-Cartan Theory of Gravity

1973 ◽  
Vol 185 ◽  
pp. 631 ◽  
Author(s):  
David G. Kerlick
Keyword(s):  
Neutron Stars ◽  
Theory Of Gravity ◽  
Cartan Theory

A formulation of Newton–Cartan gravity and quantum mechanics using D-differentiation

2019 ◽  
Vol 16 (04) ◽  
pp. 1950057
Author(s):  
D. J. Hurley ◽  
M. A. Vandyck
Keyword(s):  
Quantum Mechanics ◽  
Relativistic Quantum ◽  
Relativistic Quantum Mechanics ◽  
Classical Gravity ◽  
Theory Of Gravity ◽  
Cartan Theory

The Newton–Cartan theory of gravity is expressed in the language of [Formula: see text]-differentiation. A characteristic of this approach is that the same framework accommodates, together with classical gravity, also non-relativistic Quantum Mechanics (coupled to gravity), both in its standard Schrödingerian form and in that of de Broglie and Bohm.

scholarly journals Torsional oscillations of neutron stars in scalar-tensor theory of gravity

2014 ◽  
Vol 90 (12) ◽  
Author(s):  
Hector O. Silva ◽  
Hajime Sotani ◽  
Emanuele Berti ◽  
Michael Horbatsch
Keyword(s):  
Neutron Stars ◽  
Scalar Tensor Theory ◽  
Torsional Oscillations ◽  
Tensor Theory ◽  
Theory Of Gravity

scholarly journals Coalescence of binary neutron stars in a scalar-tensor theory of gravity

2014 ◽  
Vol 89 (8) ◽  
Author(s):  
Masaru Shibata ◽  
Keisuke Taniguchi ◽  
Hirotada Okawa ◽  
Alessandra Buonanno
Keyword(s):  
Neutron Stars ◽  
Scalar Tensor Theory ◽  
Tensor Theory ◽  
Theory Of Gravity ◽  
Binary Neutron Stars

scholarly journals Neutron stars in $$f(\mathtt {R,L_m})$$ gravity with realistic equations of state: joint-constrains with GW170817, massive pulsars, and the PSR J0030+0451 mass-radius from NICER data

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
R. V. Lobato ◽  
G. A. Carvalho ◽  
C. A. Bertulani
Keyword(s):  
Neutron Stars ◽  
Equations Of State ◽  
Matter Density ◽  
Hydrostatic Equilibrium ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Equilibrium Equations ◽  
Wave Event ◽  
Theory Of Gravity ◽  
First Time

AbstractIn this work, we investigate neutron stars (NS) in $$f(\mathtt {R,L_m})$$ f ( R , L m ) theory of gravity for the case $$f(\mathtt {R,L_m})= \mathtt {R}+ \mathtt {L_m}+ \sigma \mathtt {R}\mathtt {L_m}$$ f ( R , L m ) = R + L m + σ R L m , where $$\mathtt {R}$$ R is the Ricci scalar and $$\mathtt {L_m}$$ L m the Lagrangian matter density. In the term $$\sigma \mathtt {R}\mathtt {L_m}$$ σ R L m , $$\sigma $$ σ represents the coupling between the gravitational and particles fields. For the first time the hydrostatic equilibrium equations in the theory are solved considering realistic equations of state and NS masses and radii obtained are subject to joint constrains from massive pulsars, the gravitational wave event GW170817 and from the PSR J0030+0451 mass-radius from NASA’s Neutron Star Interior Composition Explorer (NICER) data. We show that in this theory of gravity, the mass-radius results can accommodate massive pulsars, while the general theory of relativity can hardly do it. The theory also can explain the observed NS within the radius region constrained by the GW170817 and PSR J0030+0451 observations for masses around $$1.4~M_{\odot }$$ 1.4 M ⊙ .

scholarly journals Phantom dark energy from scalar-torsion coupling

2020 ◽  
pp. 2050331
Author(s):  
Nikodem J. Popławski
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Lagrangian Density ◽  
Kinetic Term ◽  
Equivalent Formulation ◽  
Phantom Dark Energy ◽  
General Relativistic ◽  
Theory Of Gravity ◽  
Cartan Theory

We show that a scalar field without a kinetic term in the Lagrangian density, coupled to the covariant divergence of the torsion vector in the Einstein–Cartan theory of gravity, becomes kinetic in its general-relativistic equivalent formulation. The resulting kinetic term is negative: such a scalar field could be a source of phantom dark energy.

scholarly journals Superdense Stellar Configurations in the Bimetric Scalar-Tensor Theory of Gravity

2018 ◽  
pp. 327-337
Author(s):  
L. Sh. Grigorian ◽  
H. F. Khachatryan ◽  
A. A. Saharian
Keyword(s):  
General Relativity ◽  
Scalar Field ◽  
Neutron Stars ◽  
White Dwarfs ◽  
Coupling Parameter ◽  
Spherically Symmetric ◽  
Scalar Tensor Theory ◽  
Metric Tensor ◽  
Tensor Theory ◽  
Theory Of Gravity

Models of static spherically-symmetric stellar configurations are discussed within the framework of the Bimetric scalar-tensor theory of gravity. The latter, in addition to the metric tensor and the scalar field, contains a background metric tensor as an absolute variable of the theory. The simplest variant of the theory with a constant coupling parameter and with a zero cosmological function is considered. The analysis includes both the white dwarfs and neutron stars. It is shown that, depending on the value of the theory parameter, the corresponding masses can be notably larger than those in general relativity.

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