Article
Astronomy & Astrophysics
Francisco Cabral, Francisco S. N. Lobo, Diego Rubiera-Garcia
Summary: In this study, the effects of torsion-fermionic interaction on the energy levels of fermions in Riemann-Cartan geometry are investigated using a model-independent approach. Interesting Zeeman-like effects on the energy levels of fermions and anti-fermions are found, depending on their alignment with respect to the axial vector part of the torsion. The study also discusses non-minimal couplings between fermionic fields and torsion in Einstein-Cartan theory and its extension to include parity-breaking interactions. Furthermore, the potential detection of torsion effects in astrophysics, cosmology, and solid state physics is elaborated using current capabilities.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
Klaus Morawetz
Summary: The Einstein-Cartan equations in first-order action of torsion are explored, deriving consistence conditions for the torsion parameters from the Belinfante-Rosenfeld equation. Inside matter, torsion is determined by spin, resulting in an extended Oppenhaimer-Volkov equation. Outside matter, a new solution is found with torsion completely determined by the metric.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Physics, Nuclear
Ammar Kasem, Shaaban Khalil
Summary: This paper revisits inflation within the framework of Einstein-Cartan theory, demonstrating the compatibility of a particular form of torsion with the cosmological principle and gauge invariance principle. It emphasizes the crucial role of torsion vanishing at the end of inflation, leading to the reduction of Einstein-Cartan theory to General Relativity with FRW geometry.
INTERNATIONAL JOURNAL OF MODERN PHYSICS A
(2021)
Article
Astronomy & Astrophysics
Emilio Elizalde, Fernando Izaurieta, Cristian Riveros, Gonzalo Salgado, Omar Valdivia
Summary: This article studies the effects of an arbitrary dark matter spin tensor on the propagation of gravitational wave amplitude in the context of Einstein-Cartan theory. The analysis shows that the background torsion induced by an eventual dark matter spin component could lead to an anomalous dampening or amplification of the gravitational wave amplitude. However, it is proved that this effect is tiny and falls below detection thresholds, even for near-future interferometers such as LISA. Therefore, the detection of such effect is still beyond our technological capabilities.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Physics, Multidisciplinary
G. E. Volovik
Summary: The paper focuses on the elasticity theory and the use of rectangular vielbein in crystals and Dirac materials, exploring the relationship with spin gauge fields and potential extensions in gravity.
Article
Physics, Multidisciplinary
A. Baldazzi, O. Melichev, R. Percacci
Summary: We discuss theories of gravity with independent metric and connection from the perspective of effective field theory. The parity-even Lagrangian terms up to dimension four are considered, and the decomposition of the linearized action on a complete basis of spin projectors is provided. Various subclasses of Metric-Affine Gravity (MAG) theories are explored, and the existence of MAGs whose equations of motion do not have propagating degrees of freedom is pointed out. Furthermore, simple MAGs containing only a massless graviton and states of spin/parity 2(-) or 3(-) are constructed.
Article
Physics, Applied
Jiamei Kong, Rukuan Wu
Summary: We investigated the dynamics of vortices in a homogeneous two-dimensional Bose-Einstein condensate by considering the variation in condensate density. Our results demonstrate that the condensate density variation plays a crucial role when two vortices are in close proximity. Through the use of the time-dependent Lagrangian functional method and numerical simulations, we explored the variation of interaction strength between vortices with the same or different topological charges as a function of distance, and extended these findings to the case of multiple vortices. The numerical simulations confirmed the validity of our theoretical approach.
MODERN PHYSICS LETTERS B
(2022)
Article
Physics, Multidisciplinary
L. C. Garcia de Andrade
Summary: In this paper, the authors extend Shaposhnikov et al.'s parity violating Einstein-Cartan-Holst action by adding a Proca photon-torsion coupling. They evaluate the strength of the Holst term using early universe torsion and find that the interaction between the photon and spin-torsion matter is weak in Einstein-Cartan gravity. However, for dark photons, the interaction strength becomes comparable to the gravity sector. The authors also discover torsion waves related to the Immirzi parameter in the Holst-Nieh-Yan extension of EC gravity.
CANADIAN JOURNAL OF PHYSICS
(2023)
Article
Physics, Mathematical
Richard James Petti
Summary: This paper derives the elements of classical Einstein-Cartan theory (EC) from classical general relativity (GR) in two ways: using one Kerr solution in GR and a distribution of many Kerr masses in GR. The limitations in convergence computations restrict the limits from continuing to an infinitesimal length scale, impacting the derivation of EC from GR. EC enables modeling exchange of intrinsic and orbital angular momentum, strengthening the case for EC and new physics derived from EC.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2021)
Article
Mathematics, Applied
Thierry Socroun, Dominique Girardot
Summary: This paper proposes to go beyond the Einstein General Relativity theory by introducing a noncommutative geometric framework. The authors first rewrite the General Relativity theory in an intrinsic manner and then reformulate the Bianchi identities, including torsion. In order to extend the theory for noncommutative scalar fields, the definition of vector fields and connections is adapted. The particular case of scalar fields being Clifford numbers motivates further investigations on a unified formulation of the Einstein field equations and the Dirac equation.
ADVANCES IN APPLIED CLIFFORD ALGEBRAS
(2022)
Article
Physics, Multidisciplinary
Emre Dil
Summary: The interactions between spin of fermionic matter and torsion in ECSK theory generate a repulsive gravitational potential, preventing the formation of black hole singularities and potentially resulting in the creation of new space within the black hole.
INDIAN JOURNAL OF PHYSICS
(2022)
Article
Physics, Mathematical
Richard James Petti
Summary: This paper presents theoretical arguments that certain virtual bound states carry the trace component of affine torsion, contributing to the conservation of angular momentum in matter. The main evidence for this hypothesis comes from analogies with dislocations in crystals and Einstein-Cartan theory, which involve torsion.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2022)
Article
Physics, Multidisciplinary
Jiao Jing, Luo Huan-Bo, Li Lu
Summary: This research focuses on the dynamic behavior of Bose-Einstein condensates under the influence of a time-dependent periodic external magnetic field, revealing that a spin-1 Bose-Einstein condensate in a ferromagnetic state undergoes topological deformation. The study shows the formation of positive and negative magnetic monopoles at specific points in the magnetic field, leading to the creation of isolated Dirac strings.
ACTA PHYSICA SINICA
(2021)
Article
Physics, Multidisciplinary
L. C. Garcia de Andrade
Summary: Recently, gravitational and Nieh-Yan chiral anomalies have been obtained in Riemann-Cartan space-time. In this paper, a class of deformed de Sitter metrics are obtained in teleparallelism. The existence of the unmagnetized de Sitter metric without axial anomalies is proved. Modified de Sitter metrics, based on Einstein, Eddington, and Schroedinger unified theories, exhibit novel features. Non-trivial gravitational anomalies are obtained from these metrics.
CANADIAN JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
L. G. Resca
Summary: In this study, a physical picture of dark energy is developed based on the principles of quantum mechanics and general relativity. The model proposes dark energy as a Bose-Einstein condensate of cosmologically massive photons and explores its formation and properties through estimates of photon mass and investigation of statistical properties.
INDIAN JOURNAL OF PHYSICS
(2023)
Article
Astronomy & Astrophysics
Nikodem J. Poplawski
CLASSICAL AND QUANTUM GRAVITY
(2014)
Article
Astronomy & Astrophysics
Nikodem J. Poplawski
GENERAL RELATIVITY AND GRAVITATION
(2012)
Article
Astronomy & Astrophysics
Nikodem Poplawski
GENERAL RELATIVITY AND GRAVITATION
(2014)
Article
Astronomy & Astrophysics
Nikodem J. Poplawski
Article
Astronomy & Astrophysics
Nikodem Poplawski
Article
Astronomy & Astrophysics
Nikodem Poplawski
Article
Astronomy & Astrophysics
Nikodem Poplawski
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2018)
Article
Astronomy & Astrophysics
Nikodem Poplawski
MODERN PHYSICS LETTERS A
(2018)
Letter
Physics, Particles & Fields
Nikodem J. Poplawski
EUROPEAN PHYSICAL JOURNAL C
(2019)
Article
Physics, Multidisciplinary
Nikodem Poplawski
FOUNDATIONS OF PHYSICS
(2020)
Article
Astronomy & Astrophysics
Nikodem J. Poplawski
MODERN PHYSICS LETTERS A
(2020)
Article
Astronomy & Astrophysics
Nikodem J. Poplawski
Summary: The study examines the formation of a universe in a black hole with spin and torsion, suggesting that torsion could prevent a singularity and replace it with a nonsingular bounce, leading to a finite period of inflation.
GENERAL RELATIVITY AND GRAVITATION
(2021)
Article
Physics, Multidisciplinary
Nikodem Poplawski
Summary: The study suggests that gravitational collapse of a fluid sphere with spin and torsion into a black hole can be prevented from forming a singularity by the gravitational repulsion of torsion, resulting in a nonsingular bounce. Quantum particle production during contraction helps torsion dominate over shear, while particle production during expansion can lead to a finite period of inflation and produce significant amounts of matter. The resulting closed universe on the other side of the event horizon may undergo multiple bounces, creating an oscillatory universe that expands indefinitely. This suggests that our universe may have originated from a black hole.
JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS
(2021)
Article
Astronomy & Astrophysics
Nikodem Poplawski
ASTROPHYSICAL JOURNAL
(2016)
