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We analyse the non-relativistic approximation of the Dirac equation for slow fermions moving in spacetimes with a static metric, caused by the weak gravitational field of the Earth and a chameleon field, and derive the most general…

General Relativity and Quantum Cosmology · Physics 2015-06-19 A. N. Ivanov , M. Pitschmann

The covariance of loop quantum gravity studies of spherically symmetric space-times has recently been questioned. This is a reasonable worry, given that they are formulated in terms of slicing-dependent variables. We show explicitly that…

General Relativity and Quantum Cosmology · Physics 2022-02-21 Rodolfo Gambini , Javier Olmedo , Jorge Pullin

In this paper, we study the non commutative quantum dynamics of the spinorial field in the presence of a gravitational background within DeWitt's approach. By employing the vierbein formalism in the temporal state of non commutative…

High Energy Physics - Theory · Physics 2017-08-22 Abolfazl Jafari

In this paper, we present a new theoretical scenario in which both dynamical Dirac fermions and Einstein's gravity with a positive cosmological constant and torsion emerge via a spontaneous symmetry breaking in a topological phase. This…

High Energy Physics - Theory · Physics 2023-06-01 Giandomenico Palumbo

The fundamental concepts of Riemannian geometry, such as differential forms, vielbein, metric, connection, torsion and curvature, are generalized in the context of non-commutative geometry. This allows us to construct the…

High Energy Physics - Theory · Physics 2009-11-07 Nguyen Ai Viet , Kameshwar C. Wali

Starting from considerations of Bosons at the real life Compton scale we go on to a description of Fermions, specifically the Dirac equation in terms of an underlying noncommutative geometry described by the Dirac $\gamma$ matrices and…

General Physics · Physics 2007-07-18 Burra G. Sidharth

The dynamics of fermions in curved spacetime is governed by a spin connection, a part of which is contorsion, an auxiliary field independent of the metric, without dynamics but fully expressible in terms of the axial current density of…

General Relativity and Quantum Cosmology · Physics 2021-02-03 Amitabha Lahiri

In this article we present the algebraic rearrangement, or matrix inversion of the Dirac equation in a curved Riemann-Cartan spacetime with torsion, the presence of non-vanishing torsion is implied by the intrinsic spin-1/2 of the Dirac…

General Relativity and Quantum Cosmology · Physics 2018-12-18 Shaun Inglis , Peter Jarvis

The gravitational effects in the relativistic quantum mechanics are investigated. The exact Foldy-Wouthuysen transformation is constructed for the Dirac particle coupled to the static spacetime metric. As a direct application, we analyze…

General Relativity and Quantum Cosmology · Physics 2011-08-17 Yuri N. Obukhov

In the present paper we consider a theory of gravity in which not only curvature but also torsion is explicitly present in the Lagrangian, both with their own coupling constant. In particular, we discuss the couplings to Dirac fields and…

General Relativity and Quantum Cosmology · Physics 2012-12-06 Luca Fabbri , Stefano Vignolo , Cosimo Stornaiolo

We study the quantum fermions+gravity system, that is, the gravitational counterpart of QED. We start from the standard Einstein-Weyl theory, reformulated in terms of Ashtekar variables; and we construct its non- perturbative quantum theory…

General Relativity and Quantum Cosmology · Physics 2009-10-22 H A Marales-Tecotl , C Rovelli

The key ingredient for lattice regularized quantum gravity is diffeomorphism symmetry. We formulate a lattice functional integral for quantum gravity in terms of fermions. This allows for a diffeomorphism invariant functional measure and…

General Relativity and Quantum Cosmology · Physics 2015-06-03 C. Wetterich

A spinor theory on a space with linear Lie type noncommutativity among spatial coordinates is presented. The model is based on the Fourier space corresponding to spatial coordinates, as this Fourier space is commutative. When the group is…

High Energy Physics - Theory · Physics 2012-08-14 A. Shariati , M. Khorrami , A. H. Fatollahi

Building on the first variational formula of the calculus of variations, one can derive the energy-momentum conservation laws from the condition of the Lie derivative of gravitation Lagrangians along vector fields corresponding to…

General Relativity and Quantum Cosmology · Physics 2007-05-23 G. Sardanashvily , K. Kirillov

The conservation law for the orbital plus spin angular momentum of a free Dirac particle in curved spacetime requires that the affine connection has the antisymmetric part: the torsion tensor, which extends general relativity to the…

General Relativity and Quantum Cosmology · Physics 2026-04-28 Nikodem Popławski

We extend the recently developed kinematical framework for diffeomorphism invariant theories of connections for compact gauge groups to the case of a diffeomorphism invariant quantum field theory which includes besides connections also…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Thomas Thiemann

We study fermions coupled to Yang-Mills matrix models from the point of view of emergent gravity. The matrix model Dirac operator provides an appropriate coupling for fermions to the effective gravitational metric for general branes with…

High Energy Physics - Theory · Physics 2010-02-23 Daniela Klammer , Harold Steinacker

Using the Lewis-Riesenfeld method of invariants we construct explicit analytical solutions for the massless Dirac equation in 2+1 dimensions describing quasi-particles in graphene. The Hamiltonian of the system considered contains some…

Quantum Physics · Physics 2015-09-16 Boubakeur Khantoul , Andreas Fring

We present detailed pedagogical derivation of covariant derivative of fermions and some related expressions, including commutator of covariant derivatives and energy-momentum tensor of a free Dirac field. On top of that, local conformal…

General Relativity and Quantum Cosmology · Physics 2022-11-28 Ilya L. Shapiro

We discuss the propagation of fermions on generic, curved branes in IKKT-type matrix models. The Dirac operator can be understood either in terms of a Weitzenb\"ock connection, or in terms of the Levi-Civita connection with extra torsion…

High Energy Physics - Theory · Physics 2023-02-28 Emmanuele Battista , Harold C. Steinacker