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Paul A. Blaga

Publications and source records attributed to Paul A. Blaga.

7 recordsLinked to original sources
arXiv2026

Jacobi stability of circular orbits around conformally invariant Weyl gravity black holes

Weyl conformal gravity was originally proposed in the early twentieth century as an attempt to unify gravitation and electromagnetism. Since 1989, renewed interest in this fourth-order theory of gravity has emerged following the discovery of several exact black hole solutions. In this work, we investigate the timelike circular geodesics of a spherically symmetric Weyl black hole. The effective potential, the circular geodesics and their Jacobi and Lyapunov stability are discussed. Our analysis provides new insights into the stability properties of Weyl black holes and the role of the free parameters appearing in their solutions.

gr-qc↗
arXiv2021

Jacobi stability analysis of the classical restricted three body problem

The circular restricted three body problem, which considers the dynamics of an infinitesimal particle in the presence of the gravitational interaction with two massive bodies moving on circular orbits about their common center of mass, is a very useful model for investigating the behavior of real astronomical objects in the Solar System. In such a system, there are five Lagrangian equilibrium points, and one important characteristic of the motion is the existence of linearly stable equilibria at the two equilibrium points that form equilateral triangles with the primaries, in the plane of the primaries' orbit. We analyze the stability of motion in the restricted three body problem by using the concept of Jacobi stability, as introduced and developed in the Kosambi-Cartan-Chern (KCC) theory. The KCC theory is a differential geometric approach to the variational equations describing the deviation of the whole trajectory of a dynamical system with respect to the nearby ones. We obtain the general result that, from the point of view of the KCC theory and of Jacobi stability, all five Lagrangian equilibrium points of the restricted three body problem are unstable.

astro-ph.IM↗
arXiv2009

On the cyclic homology of supermatrices

The aim of this note is to show that the generalized supertrace, constructed in another paper of the author, inducing an isomorphism between the Hochschild homology of a superalgebra and that of the superalgebra of square supermatrices of a given type over $A$, induces, also, an isomorphism between the cyclic homologies of the two superalgebras.

math.KT↗
arXiv2009

The Dennis' Supertrace and the Hochschild Homology of Supermatrices

We construct, in this paper, a generalization of the Dennis trace (for matrices) to the case of the supermatrices over an arbitrary (not necessarily commutative) superalgebra with unit. By analogy with the ungraded case, we show how it is possible to use this map to construct an isomorphism from the Hochschild homology of the superalgebra to the Hochschild homology of the supermatrix algebra.

math.KT↗
arXiv1995

BRST cohomology for 2D gravity

The BRST cohomology group in the space of local functionals of the fields for the two-dimensional conformally invariant gravity is calculated. All classical local actions (ghost number equal to zero) and all candidate anomalies are given and discussed for our model.

hep-th↗