einstein gravity
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Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 73
Author(s):  
Branko Dragovich

In this paper, we introduce a new type of matter that has origin in p-adic strings, i.e., strings with a p-adic worldsheet. We investigate some properties of this p-adic matter, in particular its cosmological aspects. We start with crossing symmetric scattering amplitudes for p-adic open strings and related effective nonlocal and nonlinear Lagrangian which describes tachyon dynamics at the tree level. Then, we make a slight modification of this Lagrangian and obtain a new Lagrangian for non-tachyonic scalar field. Using this new Lagrangian in the weak field approximation as a matter in Einstein gravity with the cosmological constant, one obtains an exponentially expanding FLRW closed universe. At the end, we discuss the obtained results, i.e., computed mass of the scalar p-adic particle, estimated radius of related closed universe and noted p-adic matter as a possible candidate for dark matter.


2021 ◽  
Author(s):  
Sangwha Yi

Solutions of unified theory equations of gravity and electromagnetism has to satisfy Einstein-Maxwellequation. Specially, solution of the unified theory is generally Kerr-Newman solution in vacuum. We finallyfound the revised Einstein gravity tensor equation with new term (2-order contravariant metric tensor two timesproduct and the constant matrix) is right in Kerr-Newman solution.


2021 ◽  
Author(s):  
Sangwha Yi

Solutions of unified theory equations of gravity and electromagnetism satisfy Einstein-Maxwellequation. Hence, solutions of the unified theory is Reissner-Nordstrom solution in vacuum. We found inrevised Einstein gravity tensor equation, the condition is satisfied by 2-order contravariant metric tensor twotimes product, the constant matrix.


2021 ◽  
Author(s):  
Sangwha Yi

Solutions of unified theory equations of gravity and electromagnetism satisfy Einstein-Maxwellequation. Hence, solutions of the unified theory is Reissner-Nordstrom solution in vacuum. We found inrevised Einstein gravity tensor equation, the condition is satisfied by 2-order contravariant metric tensor twotimes product and Gauss symbol.


2021 ◽  
Author(s):  
Sangwha Yi

We found the 4-order curvature term satisfied the co-variant derivative. Einstein gravity fieldequation is consist of 2-order curvature terms. Hence, the 4-order curvature term and 2-order curvature termsmake new gravity field equation. In this point, Einstein’s gravity field equation can be modified by new 4-order curvature term because gravity field equation’s term doesn’t have to be 2-order term. Indeed, Einsteinhimself was like that, 0-order term, the cosmological term. Therefore, our theory is based on legitimate facts.


2021 ◽  
Author(s):  
Sangwha Yi

Solutions of unified theory equations of gravity and electromagnetism satisfy Einstein-Maxwellequation. Hence, solutions of the unified theory is Reissner-Nordstrom solution, Kerr-Newman solution invacuum. In this careful point, Einstein gravity field equation’s energy-momentum tensor has two sign.Therefore, according to the solution, the sign is treated. We found in revised Einstein gravity tensor equation,the condition is satisfied by 2-order contravariant metric tensor two times product and Gauss symbol..


2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Kazem Bitaghsir Fadafan ◽  
Jesús Cruz Rojas

AbstractWe study a bottom-up holographic description of the QCD colour superconducting phase in the presence of higher derivative corrections. We expand this holographic model in the context of Gauss–Bonnet (GB) gravity. The Cooper pair condensate has been investigated in the deconfinement phase for different values of the GB coupling parameter $$\lambda _{G B}$$ λ GB , we observe a change in the value of the critical chemical potential $$\mu _c$$ μ c in comparison to Einstein gravity. We find that $$\mu _c$$ μ c grows as $$\lambda _{G B}$$ λ GB increases. We add four fermion interactions and show that in the presence of these corrections the main interesting features of the model are still present and that the intrinsic attractive interaction can not be switched off. This study suggests to find GB corrections to equation of state of holographic QCD matter.


2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Alfredo Pérez

Abstract Asymptotic symmetries in Carrollian gravitational theories in 3+1 space and time dimensions obtained from “magnetic” and “electric” ultrarelativistic contractions of General Relativity are analyzed. In both cases, parity conditions are needed to guarantee a finite symplectic term, in analogy with Einstein gravity. For the magnetic contraction, when Regge-Teitelboim parity conditions are imposed, the asymptotic symmetries are described by the Carroll group. With Henneaux-Troessaert parity conditions, the asymptotic symmetry algebra corresponds to a BMS-like extension of the Carroll algebra. For the electric contraction, because the lapse function does not appear in the boundary term needed to ensure a well-defined action principle, the asymptotic symmetry algebra is truncated, for Regge-Teitelboim parity conditions, to the semidirect sum of spatial rotations and spatial translations. Similarly, with Henneaux-Troessaert parity conditions, the asymptotic symmetries are given by the semidirect sum of spatial rotations and an infinite number of parity odd supertranslations. Thus, from the point of view of the asymptotic symmetries, the magnetic contraction can be seen as a smooth limit of General Relativity, in contrast to its electric counterpart.


2021 ◽  
Vol 53 (12) ◽  
Author(s):  
Valerio Faraoni ◽  
Sonia Jose ◽  
Steve Dussault

Author(s):  
Yong Xiao ◽  
Longting Zhang

Abstract The infinite derivative theory of gravity is a generalization of Einstein gravity with many interesting properties, but the black hole solutions in this theory are still not fully understood. In the paper, we concentrate on studying the charged black holes in such a theory. Adding the electromagnetic field part to the effective action, we show how the black hole solutions around the Reissner-Nordstr{\"o}m metric can be solved perturbatively and iteratively. We further calculate the corresponding temperature, entropy and electrostatic potential of the black holes and verify the first law of thermodynamics.


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