MDPI - Publisher of Open Access Journals

23 pages, 374 KB

Open AccessArticle

Electromagnetic Kantowski–Sachs Solutions in Teleparallel F(T) Gravity

by Alexandre Landry

Symmetry 2026, 18(6), 1028; https://doi.org/10.3390/sym18061028 - 15 Jun 2026

Viewed by 195

A covariant reconstruction framework for electromagnetic Kantowski–Sachs (KS) geometries in teleparallel

F (T)

gravity is developed using the coframe/spin-connection (CSC) formalism and the Coley–Landry invariant approach. In a restricted Maxwell-compatible branch, the electromagnetic conservation laws strongly constrain the anisotropic KS scale [...] Read more.

A covariant reconstruction framework for electromagnetic Kantowski–Sachs (KS) geometries in teleparallel

F (T)

gravity is developed using the coframe/spin-connection (CSC) formalism and the Coley–Landry invariant approach. In a restricted Maxwell-compatible branch, the electromagnetic conservation laws strongly constrain the anisotropic KS scale factors and lead to the scaling

ρ_{em} \propto A_{3}^{- 4}

. The corresponding symmetric and antisymmetric field equations are derived and used to reconstruct the functional form of

F (T)

directly from the KS dynamics. Power-law and exponential ansätze generate distinct invariant reconstruction branches associated with electric, magnetic, and transverse electromagnetic sectors. The exponential branch naturally admits reduced teleparallel de Sitter limits and shifted models of the form

F (T) = f (T_{0} - T)

. The reconstructed branches describe anisotropic cosmological sectors together with local BH-interior-like sectors that may reproduce reduced BH-interior-like or RN–dS-type behaviors at the level of the KS dynamics. These branches are organized through the invariant coframe/spin-connection classification and screened using the necessary leading-order viability conditions

F_{T} > 0

and

F_{T T} > 0

. The local and branch-dependent nature of the construction is emphasized throughout. Full article

(This article belongs to the Special Issue Symmetry and Lie Algebras)

28 pages, 891 KB

Open AccessArticle

Teleparallel F(T) Electromagnetic Static Spherically Symmetric Spacetime Solutions

by Alexandre Landry

Symmetry 2026, 18(6), 891; https://doi.org/10.3390/sym18060891 - 24 May 2026

Viewed by 169

Abstract

We investigate static, spherically symmetric (SS) spacetimes in covariant teleparallel

F (T)

gravity in the presence of electromagnetic sources. Starting from the coframe/spin-connection (CSC) pair formalism, we derive the field equations and associated conservation laws, which constrain admissible electromagnetic configurations and [...] Read more.

We investigate static, spherically symmetric (SS) spacetimes in covariant teleparallel

F (T)

gravity in the presence of electromagnetic sources. Starting from the coframe/spin-connection (CSC) pair formalism, we derive the field equations and associated conservation laws, which constrain admissible electromagnetic configurations and reconstructed teleparallel sectors. A general reconstruction procedure is established, allowing the systematic construction of nonlinear teleparallel

F (T)

models for arbitrary coframe ansätze. Focusing on power-law (PL) configurations, we obtain several classes of exact solutions, including constant-radius, black-hole-like (BH-like), and wormhole-like (WH-like) branches, and analyze their horizon structures, torsion singularities, and stability properties. The inclusion of electromagnetic sources leads to new charged solutions that generalize Reissner–Nordström (RN) spacetimes and reveal modified near-horizon and asymptotic behaviors. The results are further organized within an invariant classification framework, highlighting the role of torsion in shaping the solution space. Overall, this work provides a unified and covariant approach to the construction and interpretation of physically relevant compact-object, effective cosmological, and regularized strong-field sectors in nonlinear teleparallel gravity, with potential implications for strong-field tests beyond General Relativity (GR). Full article

(This article belongs to the Special Issue Gravitational Physics, Black Holes and Space–Time Symmetry)

► Show Figures

Figure 1

40 pages, 2191 KB

Open AccessArticle

Comparing Measures of the Hubble and BAO Tensions in ΛCDM and Possible Solutions in f(Q) Gravity

by José Antonio Nájera, Indranil Banik, Harry Desmond and Vasileios Kalaitzidis

Galaxies 2026, 14(2), 19; https://doi.org/10.3390/galaxies14020019 - 9 Mar 2026

Cited by 1 | Viewed by 2245

Abstract

We test whether

f (Q)

symmetric teleparallel gravity theories can solve the Hubble tension consistently with DESI DR2 BAO. We consider three

f (Q)

functional forms: logarithmic, exponential, and hyperbolic tangent. We extend these models by allowing a cosmological [...] Read more.

We test whether

f (Q)

symmetric teleparallel gravity theories can solve the Hubble tension consistently with DESI DR2 BAO. We consider three

f (Q)

functional forms: logarithmic, exponential, and hyperbolic tangent. We extend these models by allowing a cosmological constant, and compare to phenomenological models with a flexible exponential, hyperbolic secant, and polynomial decay addition to the standard

Λ

CDM

H (z)

. We test these models against DESI DR2 BAO, CMB (Planck 2018 + SPT-3G + ACT DR6), local

H_{0}

, and Cosmic Chronometer data. The logarithmic and hyperbolic tangent

f (Q)

models do not provide an adequate solution, but the exponential model does. Furthermore, it slightly reduces the

(Ω_{m}, H_{0} r_{d})

parameter space tension between CMB and BAO datasets to

2.56 σ

, down from

2.65 σ

for

Λ

CDM. Although

Λ

CDM faces only

1.66 σ

tension in DESI data space, the

1 σ

higher tension in parameter space suggests a real anomaly. The models assisted by the cosmological constant perform slightly better still, at the cost of undermined theoretical motivation. They also perform poorly once local

H_{0}

measurements are included. The phenomenological models fit all data reasonably well, yet the best-fitting models predict isotropically averaged BAO distances exceeding the DESI DR2 measurements at all redshifts. This highlights the difficulties of finding a theoretically motivated solution to the Hubble tension while remaining consistent with BAO data. Full article

(This article belongs to the Special Issue Theoretical and Observational Approaches to the Hubble Tension in Cosmology)

► Show Figures

Figure 1

19 pages, 616 KB

Open AccessArticle

Study of Physical GUP-Influenced Properties of Regular Black Holes in the Context of

f (Q, B_{Q})

Gravity

by Riasat Ali, Tiecheng Xia and Rimsha Babar

Physics 2025, 7(4), 55; https://doi.org/10.3390/physics7040055 - 4 Nov 2025

Viewed by 1008

Abstract

This paper analyzes how the generalized uncertainty principle (GUP) affects the thermodynamic properties in a regular black hole spacetime in the context of

f (Q, B_{Q})

symmetric teleparallel gravity, with an arbitrary action f as a function of non-metric [...] Read more.

This paper analyzes how the generalized uncertainty principle (GUP) affects the thermodynamic properties in a regular black hole spacetime in the context of

f (Q, B_{Q})

symmetric teleparallel gravity, with an arbitrary action f as a function of non-metric scalar

Q

and the boundary

B_{Q}

. We analyze a GUP-influenced semi-classical technique in regular black hole spacetime that incorporates the quantum tunneling mechanism. The GUP-influenced temperature results show that the GUP term reduced the vector particles’ radiation in the context of

f (Q, B_{Q})

gravity. Moreover, we explore the GUP-influenced entropy as well as the GUP-influenced emission energy, it can help to explain the complex interactions between quantum gravity and astrophysics and highlights the important role of GUP-influenced thermodynamic properties (Hawking temperature, entropy and emission energy) in regular black hole spacetime in the context of

f (Q, B_{Q})

gravity. We graphically analyze the effects of different parameters on black hole geometry. Full article

(This article belongs to the Special Issue Beyond the Standard Models of Physics and Cosmology: 2nd Edition)

► Show Figures

Figure 1

19 pages, 322 KB

Open AccessArticle

Weak Gravity Limit in Newer General Relativity

by Alexey Golovnev, Sofia Klimova, Alla N. Semenova and Vyacheslav P. Vandeev

Universe 2025, 11(5), 149; https://doi.org/10.3390/universe11050149 - 3 May 2025

Cited by 2 | Viewed by 1243

Abstract

We analyse linearised field equations around the Minkowski metric, with its standard flat parallel transport structure, in models of newer GR, which refers to quadratic actions in terms of a nonmetricity tensor. We show that half of the freedom in choosing the model [...] Read more.

We analyse linearised field equations around the Minkowski metric, with its standard flat parallel transport structure, in models of newer GR, which refers to quadratic actions in terms of a nonmetricity tensor. We show that half of the freedom in choosing the model parameters is immediately fixed by asking for reasonable properties of tensors and vectors, defined with respect to spatial rotations, and we accurately describe the much more complicated sector of scalars. In particular, we show that, from the teleparallel viewpoint, the STEGR model with an additional term of a gradient squared of the metric determinant exhibits one and a half new dynamical modes, and not just one new dynamical mode as it was previously claimed. Full article

(This article belongs to the Special Issue Geometric Theories of Gravity)

32 pages, 920 KB

Open AccessArticle

Scalar Field Static Spherically Symmetric Solutions in Teleparallel F(T) Gravity

by Alexandre Landry

Mathematics 2025, 13(6), 1003; https://doi.org/10.3390/math13061003 - 19 Mar 2025

Cited by 5 | Viewed by 2394

Abstract

We investigate in this paper the static radial coordinate-dependent spherically symmetric spacetime in teleparallel

F (T)

gravity for a scalar field source. We begin by setting the static field equations (FEs) to be solved and solve the conservation laws for scalar [...] Read more.

We investigate in this paper the static radial coordinate-dependent spherically symmetric spacetime in teleparallel

F (T)

gravity for a scalar field source. We begin by setting the static field equations (FEs) to be solved and solve the conservation laws for scalar field potential solutions. We simplify the FEs and then find a general formula for computing the new teleparallel

F (T)

solutions applicable for any scalar field potential

V (T)

and coframe ansatz. We compute new non-trivial teleparallel

F (T)

solutions by using a power-law coframe ansatz for each scalar potential case arising from the conservation laws. We apply this formula to find new exact teleparallel

F (T)

solutions for several cases of coframe ansatz parameter. The new

F (T)

solution classes will be relevant for studying the models close to Born–Infeld and/or scalarized Black Hole (BH) solutions inside the dark energy (DE) described by a fundamental scalar field such as quintessence, phantom energy or quintom system, to name only those types. Full article

(This article belongs to the Special Issue Geometry and Symmetry in Mathematical Physics)

► Show Figures

Figure 1

52 pages, 652 KB

Open AccessArticle

Scalar Field Kantowski–Sachs Solutions in Teleparallel F(T) Gravity

by Alexandre Landry

Universe 2025, 11(1), 26; https://doi.org/10.3390/universe11010026 - 16 Jan 2025

Cited by 7 | Viewed by 1762

Abstract

In this paper, we investigate time-dependent Kantowski–Sachs spherically symmetric teleparallel

F (T)

gravity with a scalar field source. We begin by setting the exact field equations to be solved and solve conservation laws for possible scalar field potential,

V (ϕ)

, [...] Read more.

In this paper, we investigate time-dependent Kantowski–Sachs spherically symmetric teleparallel

F (T)

gravity with a scalar field source. We begin by setting the exact field equations to be solved and solve conservation laws for possible scalar field potential,

V (ϕ)

, solutions. Then, we find new non-trivial teleparallel

F (T)

solutions by using power-law and exponential ansatz for each potential case arising from conservation laws, such as linear, quadratic, or logarithmic, to name a few. We find a general formula allowing us to compute all possible new teleparallel

F (T)

solutions applicable for any scalar field potential and ansatz. Then, we apply this formula and find a large number of exact and approximate new teleparallel

F (T)

solutions for several types of cases. Some new

F (T)

solution classes may be relevant for future cosmological applications, especially concerning dark matter, dark energy quintessence, phantom energy leading to the Big Rip event, and quintom models of physical processes. Full article

(This article belongs to the Special Issue Dark Energy and Dark Matter)

19 pages, 337 KB

Open AccessArticle

Semi-Classical Limit and Quantum Corrections in Non-Coincidence Power-Law f(Q)-Cosmology

by Andronikos Paliathanasis

Axioms 2024, 13(9), 619; https://doi.org/10.3390/axioms13090619 - 11 Sep 2024

Cited by 2 | Viewed by 1459

Abstract

Within the framework of symmetric teleparallel

f (Q)

-gravity, using a connection defined in the non-coincidence gauge, we derive the Wheeler–DeWitt equation of quantum cosmology. The gravitational field equation in

f (Q)

-gravity permits a minisuperspace description, rendering the Wheeler–DeWitt equation a single [...] Read more.

Within the framework of symmetric teleparallel

f (Q)

-gravity, using a connection defined in the non-coincidence gauge, we derive the Wheeler–DeWitt equation of quantum cosmology. The gravitational field equation in

f (Q)

-gravity permits a minisuperspace description, rendering the Wheeler–DeWitt equation a single inhomogeneous partial differential equation. We use the power-law

f (Q) = f_{0} Q^{μ}

model, and with the application of linear quantum observables, we calculate the wave function of the universe. Finally, we investigate the effects of the quantum correction terms in the semi-classical limit. Full article

(This article belongs to the Special Issue Mathematical Cosmology)

31 pages, 455 KB

Open AccessArticle

Kantowski–Sachs Spherically Symmetric Solutions in Teleparallel F(T) Gravity

by Alexandre Landry

Symmetry 2024, 16(8), 953; https://doi.org/10.3390/sym16080953 - 25 Jul 2024

Cited by 11 | Viewed by 2360

Abstract

In this paper, we investigate time-dependent Kantowski–Sachs spherically symmetric teleparallel

F (T)

gravity in vacuum and in a perfect isotropic fluid. We begin by finding the field equations and solve for new teleparallel

F (T)

solutions. With a power-law [...] Read more.

In this paper, we investigate time-dependent Kantowski–Sachs spherically symmetric teleparallel

F (T)

gravity in vacuum and in a perfect isotropic fluid. We begin by finding the field equations and solve for new teleparallel

F (T)

solutions. With a power-law ansatz for the co-frame functions, we find new non-trivial teleparallel

F (T)

vacuum solutions. We then proceed to find new non-trivial teleparallel

F (T)

solutions in a perfect isotropic fluid with both linear and non-linear equations of state. We find a great number of new exact and approximated teleparallel

F (T)

solutions. These classes of new solutions are relevant for future cosmological applications. Full article

(This article belongs to the Special Issue Symmetry and Applications of Differential Geometry to the Differential Equations of Mathematical Physics)

38 pages, 522 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Static Spherically Symmetric Perfect Fluid Solutions in Teleparallel F(T) Gravity

by Alexandre Landry

Axioms 2024, 13(5), 333; https://doi.org/10.3390/axioms13050333 - 17 May 2024

Cited by 14 | Viewed by 2369

Abstract

In this paper, we investigate static spherically symmetric teleparallel

F (T)

gravity containing a perfect isotropic fluid. We first write the field equations and proceed to find new teleparallel

F (T)

solutions for perfect isotropic and linear fluids. By [...] Read more.

In this paper, we investigate static spherically symmetric teleparallel

F (T)

gravity containing a perfect isotropic fluid. We first write the field equations and proceed to find new teleparallel

F (T)

solutions for perfect isotropic and linear fluids. By using a power-law ansatz for the coframe components, we find several classes of new non-trivial teleparallel

F (T)

solutions. We also find a new class of teleparallel

F (T)

solutions for a matter dust fluid. After, we solve the field equations for a non-linear perfect fluid. Once again, there are several new exact teleparallel

F (T)

solutions and also some approximated teleparallel

F (T)

solutions. All these classes of new solutions may be relevant for future cosmological and astrophysical applications. Full article

(This article belongs to the Special Issue Advances in Differential Geometry and Mathematical Physics)

21 pages, 378 KB

Open AccessArticle

Reconstructing Modified and Alternative Theories of Gravity

by Dalia Saha, Manas Chakrabortty and Abhik Kumar Sanyal

Universe 2024, 10(1), 44; https://doi.org/10.3390/universe10010044 - 17 Jan 2024

Cited by 7 | Viewed by 3569

Abstract

A viable radiation-dominated era in the early universe is best described by the standard (FLRW) model of cosmology. In this short review, we demonstrate reconstruction of the forms of

F (R)

in the modified theory of gravity and the metric compatible [...] Read more.

A viable radiation-dominated era in the early universe is best described by the standard (FLRW) model of cosmology. In this short review, we demonstrate reconstruction of the forms of

F (R)

in the modified theory of gravity and the metric compatible

F (T)

together with the symmetric

F (Q)

in alternative teleparallel theories of gravity, from different perspectives, primarily rendering emphasis on a viable FLRW radiation era. Inflation has also been studied for a particular choice of the scalar potential. The inflationary parameters are found to agree appreciably with the recently released observational data. Full article

(This article belongs to the Collection Modified Theories of Gravity and Cosmological Applications)

15 pages, 295 KB

Open AccessArticle

Conventionalism, Cosmology and Teleparallel Gravity

by Laur Järv and Piret Kuusk

Universe 2024, 10(1), 1; https://doi.org/10.3390/universe10010001 - 19 Dec 2023

Cited by 5 | Viewed by 2778

Abstract

We consider homogeneous and isotropic cosmological models in the framework of three geometrical theories of gravitation. In Einstein’s general relativity, they are given in terms of the curvature of the Levi-Civita connection in torsion-free metric spacetimes; in the teleparallel equivalent of general relativity, [...] Read more.

We consider homogeneous and isotropic cosmological models in the framework of three geometrical theories of gravitation. In Einstein’s general relativity, they are given in terms of the curvature of the Levi-Civita connection in torsion-free metric spacetimes; in the teleparallel equivalent of general relativity, they are given in terms of the torsion of flat metric spacetimes; and in the symmetric teleparallel equivalent of general relativity, they are given in terms of the nonmetricity of flat torsion-free spacetimes. We argue that although these three formulations seem to be different, the corresponding cosmological models are in fact equivalent and their choice is conventional. Full article

(This article belongs to the Special Issue The Friedmann Cosmology: A Century Later)

18 pages, 766 KB

Open AccessArticle

Yukawa–Casimir Wormholes in f(Q) Gravity

by Ambuj Kumar Mishra, Shweta and Umesh Kumar Sharma

Universe 2023, 9(4), 161; https://doi.org/10.3390/universe9040161 - 27 Mar 2023

Cited by 30 | Viewed by 2814

Abstract

Casimir energy is always suggested as a possible source to create a traversable wormhole. It is also used to demonstrate the existence of negative energy, which can be created in a lab. To generalize this idea, Yukawa modification of a Casimir source has [...] Read more.

Casimir energy is always suggested as a possible source to create a traversable wormhole. It is also used to demonstrate the existence of negative energy, which can be created in a lab. To generalize this idea, Yukawa modification of a Casimir source has been considered in Remo Garattini (Eur. Phys. J. C 81 no.9, 824, 2021). In this work, we explore the Yukawa–Casimir wormholes in symmetric teleparallel gravity. We have taken four different forms of

f (Q)

to obtain wormhole solutions powered by the original Casimir energy source and Yukawa modification of the Casimir energy source. In power law form

f (Q) = α Q^{2} + β

and quadratic form

f (Q) = α Q^{2} + β Q + γ

, where

α, β, γ

are constants and Q is non-metricity scalar, we analyze that wormhole throat is filled with non-exotic matter. We find self-sustained traversable wormholes in the Casimir source where null energy conditions are violated in all specific forms of

f (Q)

, while after Yukawa modification, it is observed that violation of null energy conditions is restricted to some regions in the vicinity of the throat. Full article

(This article belongs to the Section Gravitation)

► Show Figures

Figure 1

10 pages, 407 KB

Open AccessArticle

Parametrization of Deceleration Parameter in f(Q) Gravity

by Gaurav N. Gadbail, Sanjay Mandal and Pradyumn Kumar Sahoo

Physics 2022, 4(4), 1403-1412; https://doi.org/10.3390/physics4040090 - 13 Dec 2022

Cited by 71 | Viewed by 5768

Abstract

In this paper, we investigate the modified symmetric teleparallel gravity or

f (Q)

gravity, where Q is the nonmetricity, to study the evolutionary history of the universe by considering the functional form of

f (Q) = α Q^{n}

[...] Read more.

In this paper, we investigate the modified symmetric teleparallel gravity or

f (Q)

gravity, where Q is the nonmetricity, to study the evolutionary history of the universe by considering the functional form of

f (Q) = α Q^{n}

, where

α

and n are constants. Here, we consider the parametrization form of the deceleration parameter as

q = q_{0} + q_{1} z / {(1 + z)}^{2}

(with the parameters

q_{0}

(q

at

z = 0)

,

q_{1}

, and the redshift, z), which provides the desired property for a sign flip from a decelerating to an accelerating phase. We obtain the solution of the Hubble parameter by examining the mentioned parametric form of q, and then we impose the solution in Friedmann equations. Employing the Bayesian analysis for the Observational Hubble data (OHD), we estimated the constraints on the associated free parameters

(H_{0}, q_{0}, q_{1})

with

H_{0}

the current Hubble parameter to determine if this model may challenge the

Λ

CDM (

Λ

cold dark matter with the cosmological constant,

Λ

) limitations. Furthermore, the constrained current value of the deceleration parameter

q_{0} = - 0 . 832_{- 0.091}^{+ 0.091}

shows that the present universe is accelerating. We also investigate the evolutionary trajectory of the energy density, pressure, and EoS (equation-of-state) parameters to conclude the accelerating behavior of the universe. Finally, we try to demonstrate that the considered parametric form of the deceleration parameter is compatible with

f (Q)

gravity. Full article

(This article belongs to the Special Issue New Advances in Quantum Geometry)

► Show Figures

Figure 1

22 pages, 1520 KB

Open AccessArticle

Wormhole Solutions in Symmetric Teleparallel Gravity with Noncommutative Geometry

by Zinnat Hassan, Ghulam Mustafa and Pradyumn Kumar Sahoo

Symmetry 2021, 13(7), 1260; https://doi.org/10.3390/sym13071260 - 14 Jul 2021

Cited by 60 | Viewed by 4094

Abstract

This article describes the study of wormhole solutions in

f (Q)

gravity with noncommutative geometry. Here, we considered two different

f (Q)

models—a linear model

f (Q) = α Q

and an exponential model [...] Read more.

This article describes the study of wormhole solutions in

f (Q)

gravity with noncommutative geometry. Here, we considered two different

f (Q)

models—a linear model

f (Q) = α Q

and an exponential model

f (Q) = Q - α (1 - e^{- Q})

, where Q is the non-metricity and

α

is the model parameter. In addition, we discussed the existence of wormhole solutions with the help of the Gaussian and Lorentzian distributions of these linear and exponential models. We investigated the feasible solutions and graphically analyzed the different properties of these models by taking appropriate values for the parameter. Moreover, we used the Tolman–Oppenheimer–Volkov (TOV) equation to check the stability of the wormhole solutions that we obtained. Hence, we found that the wormhole solutions obtained with our models are physically capable and stable. Full article

(This article belongs to the Special Issue Quantum Gravity Condensates)

► Show Figures

Figure 1

Search Results (19)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (19)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI