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We discuss a class of teleparallel scalar-torsion theories of gravity, which is parametrized by five free functions of the scalar field. The theories are formulated covariantly using a flat, but non-vanishing spin connection. We show how…

General Relativity and Quantum Cosmology · Physics 2018-09-12 Manuel Hohmann

Symmetric teleparallel gravity (STG) is a gravity theory which takes non-metricity tensor to describe gravity effects. In the STG framework, we study the conformal equivalent scalar-tensor theory of f(Q) model and calculate the cosmological…

General Relativity and Quantum Cosmology · Physics 2024-04-26 Dehao Zhao

In this paper, we study the effects of parity violation on non-gaussianities of primordial gravitational waves in the framework of Ho\v{r}ava-Lifshitz theory of gravity, in which high-order spatial derivative operators, including the ones…

High Energy Physics - Theory · Physics 2013-10-29 Tao Zhu , Wen Zhao , Yongqing Huang , Anzhong Wang , Qiang Wu

Teleparallel gravity offers a new avenue in which to construct gravitational models beyond general relativity. While teleparallel gravity can be framed in a way to be dynamically equivalent to general relativity, its modifications are…

General Relativity and Quantum Cosmology · Physics 2021-01-28 Sebastian Bahamonde , Viktor Gakis , Stella Kiorpelidi , Tomi Koivisto , Jackson Levi Said , Emmanuel N. Saridakis

We investigate the cosmological perturbations around all three branches of spatially flat universe with different connections in symmetric teleparallel gravity. The model we consider can cover both the case of f(Q) model and that of the…

General Relativity and Quantum Cosmology · Physics 2023-12-06 Haomin Rao , Chunhui Liu , Chao-Qiang Geng

We analyze the construction of conformal theories of gravity in the realm of teleparallel theories. We first present a family of conformal theories which are quadratic in the torsion tensor and are constructed out of the tetrad field and of…

General Relativity and Quantum Cosmology · Physics 2012-01-19 J. W. Maluf , F. F. Faria

Anomalous parity violation in four dimensions would be significant for phenomenology (baryogenesis, gravitational waves) and mathematical physics. Over the past decade, there has been a controversy in the literature as to whether free Weyl…

High Energy Physics - Theory · Physics 2024-11-04 Rémy Larue , Jérémie Quevillon , Roman Zwicky

General Relativity and its higher derivative extensions have symmetric teleparallel reformulations in terms of the non-metricity tensor within a torsion-free and flat geometry. These notes present a derivation of the exact propagator for…

General Relativity and Quantum Cosmology · Physics 2018-11-07 Aindriú Conroy , Tomi Koivisto

In this paper, we study a class of higher derivative, non-local gravity which admits homogeneous and isotropic non-singular, bouncing universes in the absence of matter. At the linearized level, the theory propagates only a scalar degree of…

General Relativity and Quantum Cosmology · Physics 2020-07-28 K. Sravan Kumar , Shubham Maheshwari , Anupam Mazumdar , Jun Peng

It is well-known that General Relativity (GR) in three spacetime dimensions (3D) has no well-defined Newtonian limit. Recently, a static solution mimicking the behaviour of the expected Newtonian potential has been found in arXiv:1904.11001…

High Energy Physics - Theory · Physics 2020-07-29 Mehmet Kemal Gumus , Gokhan Alkac

We consider a recently proposed class of extended teleparallel theories of gravity, which entail a scalar field which is non-minimally coupled to the torsion of a flat, metric-compatible connection. This class of scalar-torsion theories of…

General Relativity and Quantum Cosmology · Physics 2020-01-24 Elena D. Emtsova , Manuel Hohmann

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

We consider the most general teleparallel theory of gravity whose action is a linear combination of the five scalar invariants which are quadratic in the torsion tensor. Since two of these invariants possess odd parity, they naturally allow…

General Relativity and Quantum Cosmology · Physics 2021-05-11 Manuel Hohmann , Christian Pfeifer

Teleparallel gravity can be seen as a gauge theory for the translation group. As such, its fundamental field is neither the tetrad nor the metric, but a gauge potential assuming values in the Lie algebra of the translation group. This gauge…

General Relativity and Quantum Cosmology · Physics 2014-11-17 R. Aldrovandi , J. G. Pereira , K. H. Vu

It was recently found that, when linearised in the absence of matter, 58 cases of the general gravitational theory with quadratic curvature and torsion are (i) free from ghosts and tachyons and (ii) power-counting renormalisable. We inspect…

General Relativity and Quantum Cosmology · Physics 2021-10-13 W. E. V. Barker , A. N. Lasenby , M. P. Hobson , W. J. Handley

We investigate the particle content of parity-preserving Weyl gauge theories of gravity (WGT$^+$) about a Minkowski background. Within a subset of the full theory, we use a systematic method previously presented in [arXiv:1812.02675] to…

General Relativity and Quantum Cosmology · Physics 2021-07-21 Yun-Cherng Lin , Michael P. Hobson , Anthony N. Lasenby

We study dynamics of generalized tachyon scalar field in the framework of teleparallel gravity. This model is an extension of tachyonic teleparallel dark energy model which has been proposed in [26]. In contrast with tachyonic teleparallel…

General Relativity and Quantum Cosmology · Physics 2014-08-04 Behnaz Fazlpour , Ali Banijamali

Understanding the role of higher derivatives is probably one of the most relevant questions in quantum gravity theory. Already at the semiclassical level, when gravity is a classical background for quantum matter fields, the action of…

General Relativity and Quantum Cosmology · Physics 2014-10-10 Ilya L. Shapiro , Ana M. Pelinson , Filipe de O. Salles

We study the cosmology of a covariant scalar field respecting a Galilean symmetry in flat space-time. We show the existence of a tracker solution that finally approaches a de Sitter fixed point responsible for cosmic acceleration today. The…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 Antonio De Felice , Shinji Tsujikawa

We propose the simplest model of teleparallel dark energy with purely a non-minimal coupling to gravity but no self-potential, a single model possessing various interesting features: simplicity, self-potential-free, the guaranteed late-time…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Je-An Gu , Chung-Chi Lee , Chao-Qiang Geng