Article
Astronomy & Astrophysics
Mindaugas Karciauskas, Stanislav Rusak, Alejandro Saez
Summary: With the help of the tachyonic trapping mechanism, various issues related to quintessential inflation models can potentially be solved. This mechanism involves introducing a trapping field with a spontaneously broken symmetry potential. When the quintessential inflaton reaches the critical point, a burst of particle production occurs, reheating the Universe and trapping the inflaton away from the minimum of its potential. However, the self-interactions of the trapping field suppress particle production and decrease the efficiency of this process. A method for computing the magnitude of this suppression is developed, and the parameter space where the mechanism can be effectively applied is explored.
Article
Physics, Nuclear
Mingzhe Li, Yicen Mou, Haomin Rao, Dehao Zhao
Summary: This study investigates the possibilities of generating baryon number asymmetry under thermal equilibrium within the frameworks of teleparallel and symmetric teleparallel gravities, finding that gravitational baryogenesis mechanisms in these frameworks produce a baryon-to-entropy ratio too small to be consistent with observations, but gravitational leptogenesis models within both frameworks have the potential to explain the observed baryon-antibaryon asymmetry.
Review
Physics, Multidisciplinary
Sebastian Bahamonde, Konstantinos F. Dialektopoulos, Celia Escamilla-Rivera, Gabriel Farrugia, Viktor Gakis, Martin Hendry, Manuel Hohmann, Jackson Levi Said, Jurgen Mifsud, Eleonora Di Valentino
Summary: In this Review, the development of teleparallel gravity as a gauge theory of translations is comprehensively introduced. The construction of consistent teleparallel theories that respect physical conditions such as local Lorentz invariance is described. Various modified teleparallel theories of gravity are discussed and connected into general classes of covariant gravitational theories. The cosmological consequences and observational implications of teleparallel gravity are also explored, along with the application of machine learning to gravity research.
REPORTS ON PROGRESS IN PHYSICS
(2023)
Article
Physics, Particles & Fields
Lavinia Heisenberg, Manuel Hohmann, Simon Kuhn
Summary: We derive the most general homogeneous and isotropic teleparallel geometries, defined by a metric and a flat, affine connection. We find that there are five branches of connection solutions, which are connected via several limits, and can further be restricted to the torsion-free and metric-compatible cases. We apply our results to several classes of general teleparallel gravity theories and derive their cosmological dynamics for all five branches. Our results show that for large subclasses of these theories the dynamics reduce to that of closely related metric or symmetric teleparallel gravity theories, while for other subclasses up to two new scalar degrees of freedom participate in the cosmological dynamics.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Micol Benetti, Salvatore Capozziello, Gaetano Lambiase
Summary: Researchers conducted a detailed study on viable f(T) teleparallel cosmological models, including power law, exponential, and square-root exponential, analyzing their evolution at different scales. Through a combination of measurements, they obtained narrow constraints on the free parameters of these models, indicating a preference for extended gravity models in observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Reginald Christian Bernardo, Che-Yu Chen, Jackson Levi Said, Yu-Hsien Kung
Summary: This study investigates the effects of quantum fluctuations on the late Universe and explores a representative model with quantum fluctuations embedded in modified gravitational theories. The results suggest mild support for quantum corrections in cosmological models.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Csaba Balazs, Sanjay Bloor, Tomas E. Gonzalo, Will Handley, Sebastian Hoof, Felix Kahlhoefer, Marie Lecroq, David J. E. Marsh, Janina J. Renk, Pat Scott, Patrick Stoecker
Summary: In this study, a global analysis of the parameter space for axion-like particles (ALPs) is performed, leading to the lower bound of ALP mass. It is proposed that future observations of CMB spectral distortions can significantly improve the precision of this bound.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Francesca Chadha-Day
Summary: String theory compactifications may produce numerous light axion-like particles with weak electromagnetic couplings. A linear combination of these particles may have an observable coupling to electromagnetism. However, the basis in which one particle couples to electromagnetism is usually misaligned with the mass basis, resulting in mixing with other hidden particles that do not directly interact with photons. This mixing can substantially reduce the predicted signal in experiments such as the CERN Axion Solar Telescope.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Michael A. Roberts, Lorenzo Sorbo
Summary: The paper discusses how processes of particle production during inflation can increase the amplitude of scalar metric perturbations. It shows that in certain supergravity models, the potential generated by monodromy can naturally drive large field inflation. By deriving the equations of motion in models with a stabilizer, it is found that corrections from instanton-like corrections to the superpotential generate an interaction between the inflaton and its superpartner.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Mingzhe Li, Dehao Zhao
Summary: This paper explores the cosmological applications and features of cosmological perturbations in parity violating models based on symmetric teleparallel gravity. It reveals that in addition to the known parity violation in tensor perturbations, vector perturbations in this model exhibit unique characteristics, with one mode behaving as a ghost at high momentum scales, leading to vacuum instability in the quantum theory of cosmological perturbations.
Article
Physics, Multidisciplinary
Sanjay Mandal, N. Myrzakulov, P. K. Sahoo, R. Myrzakulov
Summary: Symmetric teleparallel gravity is a theory consistent with the vanishing affine connection and serves as an alternative and simpler geometric formulation of general relativity. Researchers have explored cosmological bouncing scenarios in a flat Friedmann-Limaitre-Robertson-Walker spacetime using two different Lagrangian forms of f(Q). Analysis of energy conditions and stability has been successfully conducted for both models to demonstrate a matter bounce.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Astronomy & Astrophysics
Ira Wolfson, Azadeh Maleknejad, Tomoaki Murata, Eiichiro Komatsu, Tsutomu Kobayashi
Summary: The study investigates isotropic background solutions of SU(2) gauge fields coupled to an axion field during inflation, showing that these models generally isotropize in Bianchi type-I geometry. By adding axial symmetry to the setup and using a new parametrization, the study revisits numerical analysis showing that reported numerical breakdown in the previous analysis was due to parametrization singularity, demonstrating that the system respects the cosmic no-hair conjecture with anisotropies diluting away within a few e-folds.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Jose Beltran Jimenez, Tomi S. Koivisto
Summary: In this paper, a general framework for constructing the Einstein frame within non-linear extensions of teleparallel equivalents of General Relativity is provided. It is shown that all non-linear extensions share the same quadratic action around Minkowski backgrounds. Additionally, the conformal mode can be absorbed into a Weyl rescaling of the metric at this order, disappearing from the linear spectrum.
Article
Astronomy & Astrophysics
Andronikos Paliathanasis
Summary: This article investigates the application of symmetric teleparallel f(Q)-gravity in Friedmann-Lemaître-Robertson-Walker cosmology with nonzero spatial curvature. It is found that for a nonlinear f(Q) model, there always exists the limit of General Relativity. The de Sitter solution is identified as the unique attractor, and deviations from STGR can solve the flatness problem.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Physics, Particles & Fields
Ji-Yu Cheng
Summary: This paper provides a straightforward proof of the validity of Birkhoff's theorem in modified teleparallel equivalent theories of gravity, which states that if the matter distribution is spherically symmetric, then the spacetime is static in a region where t remains timelike and (r, theta, phi) stay spacelike. This version of Birkhoff's theorem is rather trivial. The theorem also reveals that the gravitational field of a spherically symmetric distribution of matter and of the spherically symmetric vacuum spacetime are both static in modified teleparallel equivalent theories of gravity.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Particles & Fields
Christian Pfeifer, Jose Javier Relancio
Summary: This article presents a systematic analysis of how deformed relativistic kinematics can be lifted to curved spacetimes in terms of a self-consistent cotangent bundle geometry. The analysis shows that momentum space metrics can be consistently lifted to curved spacetimes if they satisfy certain conditions. The article also discusses the connection between this construction and non-commutative spacetimes.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Sebastian Bahamonde, Alexey Golovnev, Maria-Jose Guzman, Jackson Levi Said, Christian Pfeifer
Summary: This article discusses exact and perturbative spherically symmetric solutions in f(T, B)-gravity, and also presents general methods and strategies for finding spherically symmetric solutions in modified teleparallel theories of gravity using generalized Bianchi identities.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Review
Physics, Nuclear
A. Addazi, J. Alvarez-Muniz, R. Alves Batista, G. Amelino-Camelia, V Antonelli, M. Arzano, M. Asorey, J-L Atteia, S. Bahamonde, F. Bajardi, A. Ballesteros, B. Baret, D. M. Barreiros, S. Basilakos, D. Benisty, O. Birnholtz, J. J. Blanco-Pillado, D. Blas, J. Bolmont, D. Boncioli, P. Bosso, G. Calcagni, S. Capozziello, J. M. Carmona, S. Cerci, M. Chernyakova, S. Clesse, J. A. B. Coelho, S. M. Colak, J. L. Cortes, S. Das, V D'Esposito, M. Demirci, M. G. Di Luca, A. di Matteo, D. Dimitrijevic, G. Djordjevic, D. Dominis Prester, A. Eichhorn, J. Ellis, C. Escamilla-Rivera, G. Fabiano, S. A. Franchino-Vinas, A. M. Frassino, D. Frattulillo, S. Funk, A. Fuster, J. Gamboa, A. Gent, L. A. Gergely, M. Giammarchi, K. Giesel, J-F Glicenstein, J. Gracia-Bondia, R. Gracia-Ruiz, G. Gubitosi, E. Guendelman, I Gutierrez-Sagredo, L. Haegel, S. Heefer, A. Held, F. J. Herranz, T. Hinderer, J. I. Illana, A. Ioannisian, P. Jetzer, F. R. Joaquim, K-H Kampert, A. Karasu Uysal, T. Katori, N. Kazarian, D. Kerszberg, J. Kowalski-Glikman, S. Kuroyanagi, C. Lammerzahl, J. Levi Said, S. Liberati, E. Lim, I. P. Lobo, M. Lopez-Moya, G. G. Luciano, M. Manganaro, A. Marciano, P. Martin-Moruno, Manel Martinez, Mario Martinez, H. Martinez-Huerta, P. Martinez-Mirave, M. Masip, D. Mattingly, N. Mavromatos, A. Mazumdar, F. Mendez, F. Mercati, S. Micanovic, J. Mielczarek, A. L. Miller, M. Milosevic, D. Minic, L. Miramonti, V. A. Mitsou, P. Moniz, S. Mukherjee, G. Nardini, S. Navas, M. Niechciol, A. B. Nielsen, N. A. Obers, F. Oikonomou, D. Oriti, C. F. Paganini, S. Palomares-Ruiz, R. Pasechnik, V Pasic, C. Perez de los Heros, C. Pfeifer, M. Pieroni, T. Piran, A. Platania, S. Rastgoo, J. J. Relancio, M. A. Reyes, A. Ricciardone, M. Risse, M. D. Rodriguez Frias, G. Rosati, D. Rubiera-Garcia, H. Sahlmann, M. Sakellariadou, F. Salamida, E. N. Saridakis, P. Satunin, M. Schiffer, F. Schussler, G. Sigl, J. Sitarek, J. Sola Peracaula, C. F. Sopuerta, T. P. Sotiriou, M. Spurio, D. Staicova, N. Stergioulas, S. Stoica, J. Striskovic, T. Stuttard, D. Sunar Cerci, Y. Tavakoli, C. A. Ternes, T. Terzic, T. Thiemann, P. Tinyakov, M. D. C. Torri, M. Tortola, C. Trimarelli, T. Trzesniewski, A. Tureanu, F. R. Urban, E. C. Vagenas, D. Vernieri, V. Vitagliano, J-C Wallet, J. D. Zornoza
Summary: The exploration of the universe has entered a new era with the multi-messenger paradigm, providing us with more information about the universe and opening up the possibility of searching for quantum gravity phenomena.
PROGRESS IN PARTICLE AND NUCLEAR PHYSICS
(2022)
Article
Physics, Mathematical
Dagmar Laanemets, Manuel Hohmann, Christian Pfeifer
Summary: In this work, the observable effects of modified dispersion relations are studied systematically. The motion of test particles and the corrections to various observables for light are investigated. The results can be interpreted as predictions for quantum gravity or as predictions of observables in the presence of a medium that modifies the dispersion relation of light.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2022)
Article
Astronomy & Astrophysics
Sebastian Bahamonde, Ludovic Ducobu, Christian Pfeifer
Summary: Black holes play a crucial role in understanding gravitational interaction. Recent advancements in observation and detection have provided direct access to their properties and behavior, thus raising the demand for comparing models. This article investigates the existence of scalarized black holes in scalar-torsion theories of gravity and presents exact solutions for certain couplings and potential functions, as well as the possibility of establishing no-scalar-hair theorems.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Stefano Liberati, Christian Pfeifer, Javier Relancio
Summary: In this study, we investigate particle collisions near Kerr black holes by reviewing and extending proposed scenarios. By implementing the hoop conjecture, we demonstrate that nearhorizon target particle scenarios can attain ultra-high center of mass energies even for non-extremal Kerr black holes. Furthermore, we find that photons produced in these collisions can escape to infinity but have relatively low energy.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Mathematical
Manuel Hohmann, Christian Pfeifer, Nicoleta Voicu
Summary: This paper introduces a mathematical framework for action-based field theories on Finsler spacetimes and discusses the construction of appropriate configuration bundles and the use of coordinate free calculus of variations. It also proves the general covariance of natural Finsler field Lagrangians and their equivalence to the usual pointwise energy-momentum covariant conservation law in Lorentzian spacetimes.
JOURNAL OF MATHEMATICAL PHYSICS
(2022)
Article
Astronomy & Astrophysics
Manuel Hohmann, Christian Pfeifer
Summary: This study investigates tensor perturbations around the most general cosmologically symmetric backgrounds in a class of teleparallel gravity theories known as New General Relativity. The findings reveal the existence of gravitational wave birefringence and dispersion in these theories for a particular class of cosmological background geometries. The strength of this effect is determined by the spatial curvature of the cosmological background and the deviation parameter from General Relativity. The possibility of observing this effect in gravitational wave experiments is discussed.
Article
Physics, Particles & Fields
Iarley P. Lobo, Christian Pfeifer, Pedro H. Morais, Rafael Alves Batista, Valdir B. Bezerra
Summary: In this study, deformed relativistic kinematics is formulated using Finsler geometry, which allows for the construction of deformed Lorentz transformations and the investigation of the effects on time dilation. The impact on the distribution of decay products and the consequences for cosmic-ray showers are also discussed.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Mathematical
Samira Cheraghchi, Christian Pfeifer, Nicoleta Voicu
Summary: We locally classify all SO(3)-invariant four-dimensional pseudo-Finsler Berwald structures, which are Finslerian geometries closest to (spatially, or SO(3))-spherically symmetric pseudo-Riemannian ones and serve as ansatz to find solutions of Finsler gravity equations that generalize the Einstein equations. We find that there exist five classes of non-pseudo-Riemannian SO(3)-spherically symmetric pseudo-Finsler Berwald functions, which have either a heavily constrained dependence on the velocities or, up to a suitable choice of the tangent bundle coordinates, no dependence at all on the time and radial coordinates.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2023)
Article
Physics, Mathematical
Sjors Heefer, Christian Pfeifer, Jorn van Voorthuizen, Andrea Fuster
Summary: This paper investigates the local metrizability of Finsler spaces with m-Kropina metric F = alpha(1+m)beta(-m), where beta is a closed null one-form. It is shown that such a space is of Berwald type if and only if the (pseudo-)Riemannian metric alpha and one-form beta have a very specific form in certain coordinates. Furthermore, the affine connection on such an m-Kropina space is proven to be locally metrizable by a (pseudo-)Riemannian metric if and only if the Ricci tensor constructed from the affine connection is symmetric. The paper also provides counterexamples to Szabo's metrization theorem.
JOURNAL OF MATHEMATICAL PHYSICS
(2023)
Article
Astronomy & Astrophysics
Nicoleta Voicu, Annamaria Friedl-Szasz, Elena Popovici-Popescu, Christian Pfeifer
Summary: We establish necessary and sufficient conditions for pseudo-Finsler spaces with (alpha, beta)-metrics to admit a Finsler spacetime structure. This ensures the existence of a Lorentzian signature on a conic subbundle of the tangent bundle and a cone of future-pointing time-like vectors. These identified (alpha, beta)-Finsler spacetimes are potential candidates for applications in gravitational physics. Additionally, we determine the relation between the isometries of an (alpha, beta)-metric and the underlying pseudo-Riemannian metric a, including all (alpha, beta)-metrics that have isometries not shared with a.
Review
Astronomy & Astrophysics
Sebastian Bahamonde, Daniela D. Doneva, Ludovic Ducobu, Christian Pfeifer, Stoytcho S. Yazadjiev
Summary: In this paper, new scalarized black holes are discovered by coupling a scalar field with the Gauss-Bonnet invariant in teleparallel gravity. The usual Gauss-Bonnet term in four dimensions decays into two distinct boundary terms, the teleparallel Gauss-Bonnet invariants, when described in the language of torsion. These boundary terms can be coupled individually or in combinations to a scalar field, resulting in a teleparallel Gauss-Bonnet extension of the teleparallel equivalent of general relativity. The theory provides a natural extension with new phenomenology, where scalarization is triggered by torsion and exhibits distinct behavior compared to the usual Einstein-Gauss-Bonnet case.
Article
Physics, Particles & Fields
Sebastian Bahamonde, Konstantinos F. Dialektopoulos, Manuel Hohmann, Jackson Levi Said, Christian Pfeifer, Emmanuel N. Saridakis
Summary: This study focuses on the cosmological perturbation theory in f(T) gravity, which is a simple extension of the teleparallel equivalent of general relativity. The authors examine the possibility of a non-flat FLRW background solution and perform perturbations for different spatial geometries. They determine the behavior of the perturbative modes in this non-flat FLRW setting for arbitrary f(T) models and identify propagating modes.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Sebastian Bahamonde, Shokoufe Faraji, Eva Hackmann, Christian Pfeifer
Summary: The paper investigates Thick accretion disks in the framework of Born-Infeld teleparallel gravity and compares them with the Schwarzschild solution in general relativity. An observational bound on the model parameter is found.
