Related references
Note: Only part of the references are listed.
Article
Astronomy & Astrophysics
Kevork Abazajian et al.
Summary: CMB-S4 is the next-generation ground-based cosmic microwave background (CMB) experiment, designed to improve the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the universe. This study presents a forecasting framework that uses a power-spectrum-based semianalytic projection tool to optimize constraints on the tensor-to-scalar ratio. The framework is unique in its use of information from current CMB experiments to predict the effectiveness of future CMB-polarization endeavors. The study also includes map-based validation studies, allowing for additional complexity and independent verification of the forecasts.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Mingzhe Li et al.
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, Particles & Fields
Dehao Zhao
Summary: In Symmetric Teleparallel General Relativity, gravity is attributed to non-metricity. However, the coordinate system selected based on symmetry may conflict with the choice of coincident gauge. To overcome this problem, we formulate the f(Q) theory in a covariant way, allowing us to find suitable non-vanishing affine connection.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Cheng Gong et al.
Summary: This paper investigates the effects of high-order spatial derivatives on the propagation of gravitational waves due to Lorentz and parity violation. Bayesian inference is performed using modified waveforms and observational data from selected GW events to place lower bounds on the energy scales for Lorentz and parity violation. The results do not find significant evidence of Lorentz and parity violation at the fifth and sixth-order spatial derivatives terms.
Article
Astronomy & Astrophysics
Qiang Wu et al.
Summary: This paper investigates the parity violating effects on gravitational wave propagation in Nieh-Yan modified teleparallel gravity. No significant deviation from general relativity is found, placing an upper bound on the energy scale of the Nieh-Yan term.
Article
Astronomy & Astrophysics
Fabio D’Ambrosio et al.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Physics, Particles & Fields
Manuel Hohmann et al.
Summary: This study explores the teleparallel theory of gravity and identifies key couplings that play a crucial role in cosmological dynamics. The coupling of axion fields to general relativity has a significant impact on the cosmological dynamics. The research demonstrates that this type of coupling provides a path for canonical coupling between teleparallel theory and general relativity.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Nicola Bartolo et al.
Summary: The paper investigates inflation within chiral scalar-tensor theories of gravity, extending by including parity-violating operators. The study analyzes the effects of parity-violation on primordial tensor non-Gaussianity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Haomin Rao
Summary: The paper explores the use of the Nieh-Yan modified teleparallel gravity model in the Solar System, finding that it shares the same post-Newtonian parameters as general relativity and is compatible with Solar System experiments.
Article
Astronomy & Astrophysics
Manuel Hohmann
Summary: Symmetric teleparallel gravity theories focus on the nonmetricity of a flat, symmetric affine connection as the source of gravitational interaction, with recent studies exploring their cosmological implications. However, assumptions made in these studies, such as flat FLRW metric and vanishing connection coefficients, may not always be compatible. By constructing a general symmetric teleparallel geometry without coordinate constraints, it is found that coordinate systems do not always agree, limiting the class of achievable geometries. This study highlights the additional scalar quantity contributed by the symmetric teleparallel connection to cosmological dynamics, decoupling only under specific conditions.
Article
Astronomy & Astrophysics
Mingzhe Li et al.
Summary: This paper restores the local Lorentz symmetry of a gravity model by giving up the Weitzenbock condition on the spin connection, and applies the new version of the model to the universe with general Friedmann-Robertson-Walker background, obtaining some new results.
Article
Astronomy & Astrophysics
Flavio Bombacigno et al.
Summary: In this paper, the concept of the Nieh-Yan invariant is extended to generic metric-affine geometries, taking into account both torsion and nonmetricity. The properties of projective invariance and topologicity can be accommodated independently by choosing suitable parameters for the new Nieh-Yan term. Additionally, a special class of modified gravity theories is considered, in which the Immirzi parameter is promoted to a dynamical scalar field coupled to the Nieh-Yan form, leading to a revised theoretical framework for effective scalar tensor theory.
Article
Astronomy & Astrophysics
Mingzhe Li et al.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
Article
Astronomy & Astrophysics
Wen Zhao et al.
Article
Astronomy & Astrophysics
Xian Gao et al.
Review
Multidisciplinary Sciences
Hong Li et al.
NATIONAL SCIENCE REVIEW
(2019)
Article
Astronomy & Astrophysics
Aindriu Conroy et al.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2019)
Article
Astronomy & Astrophysics
M. Crisostomi et al.
Article
Physics, Multidisciplinary
B. P. Abbott et al.
PHYSICAL REVIEW LETTERS
(2017)
Article
Physics, Multidisciplinary
B. P. Abbott et al.
PHYSICAL REVIEW LETTERS
(2016)
Article
Astronomy & Astrophysics
Sergei Dyda et al.
Review
Physics, Multidisciplinary
Stephon Alexander et al.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2009)
Article
Astronomy & Astrophysics
R Jackiw et al.
