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We modify the Einstein-Schrodinger theory to include a cosmological constant $\Lambda_z$ which multiplies the symmetric metric, and we show how the theory can be easily coupled to additional fields. The cosmological constant $\Lambda_z$ is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. A. Shifflett

A covariant Lagrangian formulation of a solution to the cosmological constant problem, based on vizualising the fluctuations of the vacuum energy as a non-equilibrium process with stochastic behaviour, is presented. The variational…

Astrophysics · Physics 2016-08-30 J. W. Moffat

Using a recent thermal-field-theory approach to cosmological perturbations, the exact solutions that were found for collisionless ultrarelativistic matter are generalized to include the effects from weak self-interactions in a…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Herbert Nachbagauer , Anton K. Rebhan , Dominik J. Schwarz

General relativity can be cast as a gauge theory by introducing a tetrad field and a spin-connection. This formalism was extended by replacing the tetrad field with a mixed tensor field independent of the metric tensor in order to develop a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 E. F. Ferrari

A relativistic theory of modified gravity has been recently proposed by Bekenstein. The tensor field in Einstein's theory of gravity is replaced by a scalar, a vector, and a tensor field which interact in such a way to give Modified…

Astrophysics · Physics 2008-11-26 C. Skordis , D. F. Mota , P. G. Ferreira , C. Boehm

In absence of matter Einstein gravity with a cosmological constant $\La$ can be formulated as a scale-free theory depending only on the dimensionless coupling constant G \Lambda where G is Newton constant. We derive the conformal field…

High Energy Physics - Theory · Physics 2009-11-11 Mariano Cadoni

Einstein-like Lagrangian field theory is developed to describe elastic solid containing dislocations with finite-sized core. The framework of the Riemann-Cartan geometry in three dimensions is used, and the core self-energy is expressed by…

General Relativity and Quantum Cosmology · Physics 2024-10-08 Cyril Malyshev

We argue that our recent success in using our resummed quantum gravity approach to Einstein's general theory of relativity, in the context of the Planck scale cosmology formulation of Bonanno and Reuter, to estimate the value of the…

High Energy Physics - Phenomenology · Physics 2015-10-28 B. F. L. Ward

A generalized uncertainty principle is obtained from a conformally transformed action containing a scalar field and a unique constraint. The constraint's Lagrange multiplier is found to obey a relativistic diffusion equation transforming…

High Energy Physics - Theory · Physics 2020-04-24 Dor Gabay

Thermodynamical Behaviour of Inhomogeneous Universe with Varying $ \Lambda $ in Presence of Electromagnetic Field is obtained. $ F_{12} $ is the non-vanishing component of electromagnetic field tensor. To get a deterministic solution, it is…

General Relativity and Quantum Cosmology · Physics 2010-04-22 Anil Kumar Yadav

A special class of conformal gravity theories is proposed to solve the long standing problem of the fine-tuned cosmological constant. In the proposed model time evolution of the inflaton field leaves behind a nearly vanishing, but finite…

High Energy Physics - Phenomenology · Physics 2022-04-25 M. Yoshimura

The work shows that the associated Einstein like gravity for the Klein-Gordon field shows the spontaneous emergence of the cosmological pressure tensor density (CPTD) that in the classical limit leads to the cosmological constant (CC). Even…

General Physics · Physics 2020-07-07 Piero Chiarelli

The Einstein-Schrodinger theory is extended to include spin-0 and spin-1/2 sources, and the theory is derived from a Lagrangian density which allows other fields to be easily added. The original theory is also modified by including a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. A. Shifflett

A new set of field equations for a space-time dependent Newton's constant $G(x)$ and cosmological constant $\Lambda(x)$ in the presence of matter is presented. We prove that it represents the most general mathematically consistent,…

General Relativity and Quantum Cosmology · Physics 2021-05-19 Alfio Bonanno , Georgios Kofinas , Vasilios Zarikas

We study the constraint equations for the Einstein-scalar field system on compact manifolds. Using the conformal method we reformulate these equations as a determined system of nonlinear partial differential equations. By introducing a new…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Yvonne Choquet-Bruhat , James Isenberg , Daniel Pollack

The properties of the Melvin-type spacetime with a positive cosmological constant $\Lambda$ in $d$-dimensional Einstein--Maxwell gravity is studied. The solution is parametrised in terms of the `de Sitter radius' $\ell\propto\Lambda^{-1/2}$…

General Relativity and Quantum Cosmology · Physics 2025-09-03 Yu-Xuan Toh , Yun-Ten Chin , Ethan Quanrun Wu , Yen-Kheng Lim

In this work the exact Friedmann-Robertson-Walker equations for an Elko spinor field coupled to gravity in an Einstein-Cartan framework are presented. The torsion functions coupling the Elko field spin-connection to gravity can be exactly…

General Relativity and Quantum Cosmology · Physics 2017-09-13 S. H. Pereira , S. S. A. Pinho , J. M. Hoff da Silva , J. F. Jesus

We study a cosmological model based on the canonical Hamiltonian transformation theory. Using a linear-quadratic approach for the free gravitational De Donder-Weyl Hamiltonian $H_\mathrm{Gr}$, the model contains terms describing a…

General Relativity and Quantum Cosmology · Physics 2023-06-07 Johannes Kirsch , David Vasak , Armin van de Venn , Jürgen Struckmeier

We define `third derivative' General Relativity, by promoting the integration measure in Einstein-Hilbert action to be an arbitrary $4$-form field strength. We project out its local fluctuations by coupling it to another $4$-form field…

High Energy Physics - Theory · Physics 2022-09-21 Nemanja Kaloper

For a contravariant 4-metric which changes signature from Lorentzian to Riemannian across a spatial hypersurface, the mixed Einstein tensor is manifestly non-singular. In Gaussian normal coordinates, the metric contains a step function and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Sean A. Hayward