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Related papers: Many Faces of Mimetic Gravity

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We present an alternative cosmology based on conformal gravity, as originally introduced by H. Weyl and recently revisited by P. Mannheim and D. Kazanas. Unlike past similar attempts our approach is a purely kinematical application of the…

General Relativity and Quantum Cosmology · Physics 2010-04-30 Gabriele U. Varieschi

We use Weyl connection and Weyl geometry in order to construct novel modified gravitational theories. In the simplest case where one uses only the Weyl-connection Ricci scalar as a Lagrangian, the theory recovers general relativity.…

General Relativity and Quantum Cosmology · Physics 2025-03-12 Gerasimos Kouniatalis , Emmanuel N. Saridakis

We present a new formulation for the canonical approach to conformal (Weyl-squared) gravity and its extension by the Einstein-Hilbert term and a nonminimally coupled scalar field. For this purpose we use a unimodular decomposition of the…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Claus Kiefer , Branislav Nikolic

Causal structure, inertial path structure and compatibility with quantum mechanics demand no full Lorentz metric, but only an integrable Weyl geometry for space time (Ehlers/Pirani/Schild 1972, Audretsch e.a. 1984). A proposal of (Tann…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Erhard Scholz

In this paper we consider an extended Gauss-Bonnet gravity theory in arbitrary dimensions and in a space provided with a Weyl connection, which is torsionless but not metric-compatible, the non-metricity tensor being determined by a vector…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Jose Beltran Jimenez , Tomi S. Koivisto

The background field method is used to linearize the Weyl invariant scalar-tensor gravity, coupled with a Stueckelberg field. For a generic background metric, this action is found to be not invariant, under both diffeomorphism and…

High Energy Physics - Theory · Physics 2016-11-30 K. Abhinav , A. Shukla , P. K. Panigrahi

Weyl gravity has been advanced in the recent past as an alternative to General Relativity (GR). The theory has had some success in fitting galactic rotation curves without the need for copious amounts of dark matter. To check the viability…

Astrophysics · Physics 2008-12-30 A. Edery , M. B. Paranjape

The usual interpretation of Weyl geometry is modified in two senses. First, both the additive Weyl connection and its variation are treated as (1, 2) tensors under the action of Weyl covariant derivative. Second, a modified covariant…

General Relativity and Quantum Cosmology · Physics 2013-09-18 Fang-Fang Yuan , Yong-Chang Huang

Birkhoff's theorem is discussed in the frame of f(R) gravity by using its scalar-tensor representation. Modified gravity has become very popular at recent times as it is able to reproduce the unification of inflation and late-time…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Salvatore Capozziello , Diego Sáez-Gómez

General Relativity can be formulated in terms of a spatially Weyl invariant gauge theory called Shape Dynamics. Using this formulation, we establish a "bulk/bulk" duality between gravity and a Weyl invariant theory on spacelike Cauchy…

General Relativity and Quantum Cosmology · Physics 2013-01-23 Henrique Gomes , Sean Gryb , Tim Koslowski , Flavio Mercati

Two types of mimetic gravity models with higher derivatives of the mimetic field are analyzed in the Hamiltonian formalism. For the first type of mimetic gravity, the Ricci scalar only couples to the mimetic field and we demonstrate the…

General Relativity and Quantum Cosmology · Physics 2021-01-18 Yunlong Zheng

We construct a Weyl transverse diffeomorphism invariant theory of symmetric teleparallel gravity by employing the Weyl compensator formalism. The low-energy dynamics has a single spin two gravition without a scalar degree of freedom. By…

General Relativity and Quantum Cosmology · Physics 2022-07-06 Yu Nakayama

We show that a class of finite quantum non-local gravitational theories is conformally invariant at classical as well as at quantum level. This is actually a range of conformal anomaly-free theories in the spontaneously broken phase of the…

High Energy Physics - Theory · Physics 2018-09-03 Leonardo Modesto , Leslaw Rachwal

The foundations of Wesson's induced matter theory are analyzed. It is shown that the 5D empty bulk must be regarded rather as a Weylian space than as a Riemannian one.The framework of a Weyl-Dirac version of Wesson's theory is elaborated…

General Relativity and Quantum Cosmology · Physics 2009-11-13 Mark Israelit

We consider a Weyl invariant extension of Dirac-Born-Infeld type gravity. An appropriate choice of the metric hides the scalar degree of freedom which is required by the local scale invariance of the action at the first sight, and then a…

General Relativity and Quantum Cosmology · Physics 2010-12-27 Nahomi Kan , Takuya Maki , Kiyoshi Shiraishi

The possible role of gravity in a noncommutative geometry is investigated. Due to the Moyal *-product of fields in noncommutative geometry, it is necessary to complexify the metric tensor of gravity. We first consider the possibility of a…

High Energy Physics - Theory · Physics 2009-10-31 J. W. Moffat

We derive the chiral kinetic theory under the presence of a gravitational Riemann curvature. It is well-known that in the chiral kinetic theory there inevitably appears a redundant ambiguous vector corresponding to the choice of the Lorentz…

High Energy Physics - Theory · Physics 2021-05-06 Tomoya Hayata , Yoshimasa Hidaka , Kazuya Mameda

The mimetic gravity theory is one of the interesting modified gravity theories, which aims to unify the matter component of our universe within the power of gravity. The mimetic-like theory can also be responsible for primordial…

General Relativity and Quantum Cosmology · Physics 2024-05-14 Anxianyi Xiong , Xin-zhe Zhang , Taotao Qiu

In the standard Einstein's theory the exterior gravitational field of any static and axially symmetric stellar object can be described by means of a single function from which we obtain a metric into a four-dimensional space-time. In this…

General Relativity and Quantum Cosmology · Physics 2024-02-19 J. L. Hernández-Pastora

In these lectures we report recent work on the exact quantization of dimensionally reduced gravity, i.e. 2d non-linear (G/H)-coset space sigma-models coupled to gravity and a dilaton. Using methods developed in the context of flat space…

High Energy Physics - Theory · Physics 2007-05-23 H. Nicolai , D. Korotkin , H. Samtleben