242 citations · 632 across the 30 of their papers we have counts for
31 papers
On spherically symmetric Berwald vacuum solutions in Finsler gravity
Nicoleta Voicu, Diana - Maria Birla, Christian Pfeifer
Berwald-Finsler spacetimes are Finsler spacetimes that are closest to pseudo-Riemannian geometry, as their canonical nonlinear connection defines an affine connection on spacetime.…
From kinetic gases to an exponentially expanding universe - The Finsler-Friedmann equation
Christian Pfeifer, Nicoleta Voicu, Annamaria Friedl-Szász +1
We investigate the gravitational field of a kinetic gas beyond its usual derivation from the second moment of the one-particle distribution function (1PDF), that serves as energy-m…
Cosmological Landsberg Finsler spacetimes
Annamária Friedl-Szász, Elena Popovici-Popescu, Nicoleta Voicu +2
We locally classify all possible cosmological homogeneous and isotropic Landsberg-type Finsler structures, in 4-dimensions. Among them, we identify viable non-stationary Finsler sp…
Metric-affine cosmological models and the inverse problem of the calculus of variations. Part II: Variational bootstrapping of the CDM model
Ludovic Ducobu, Nicoleta Voicu
The method of variational bootstrapping, based on canonical variational completion, allows one to construct a Lagrangian for a physical theory depending on two sets of field variab…
Metrizability of SO(3)-invariant connections: Riemann versus Finsler
Nicoleta Voicu, Salah Gomaa Elgendi
For a torsion-free affine connection on a given manifold, which does not necessarily arise as the Levi-Civita connection of any pseudo-Riemannian metric, it is still possible that…
Metric-affine cosmological models and the inverse problem of the calculus of variations. Part 1: variational bootstrapping -- the method
Ludovic Ducobu, Nicoleta Voicu
The method of variational completion allows one to transform an (in principle, arbitrary) system of partial differential equations -- based on an intuitive ``educated guess'' -- in…
Birkhoff Theorem for Berwald Finsler spacetimes
Nicoleta Voicu, Christian Pfeifer, Samira Cheraghchi
Finsler spacetime geometry is a canonical extension of Riemannian spacetime geometry. It is based on a general length measure for curves (which does not necessarily arise from a sp…
The Finsler spacetime condition for (α,β)-metrics and their isometries
Nicoleta Voicu, Annamária Friedl-Szász, Elena Popovici-Popescu +1
For the general class of pseudo-Finsler spaces with -metrics, we establish necessary and sufficient conditions such that these admit a Finsler spacetime structure. This mean…
Four-dimensional SO(3)-spherically symmetric Berwald Finsler spaces
Samira Cheraghchi, Christian Pfeifer, Nicoleta Voicu
We locally classify all SO(3)-invariant 4-dimensional pseudo-Finsler Berwald structures. These are Finslerian geometries which are closest to (spatially, or SO(3))-spherically symm…
Mathematical foundations for field theories on Finsler spacetimes
Manuel Hohmann, Christian Pfeifer, Nicoleta Voicu
The paper introduces a general mathematical framework for action based field theories on Finsler spacetimes. As most often fields on Finsler spacetime (e.g., the Finsler fundamenta…
Modified Gravity and Cosmology: An Update by the CANTATA Network
Emmanuel N. Saridakis, Ruth Lazkoz, Vincenzo Salzano +50
General Relativity and the CDM framework are currently the standard lore and constitute the concordance paradigm. Nevertheless, long-standing open theoretical issues, as well as…
On the closure property of Lepage equivalents of Lagrangians
Nicoleta Voicu, Stefan Garoiu, Bianca Vasian
Lepage equivalents of Lagrangians are a higher order, field-theoretical generalization of the notion of Poincare-Cartan form from mechanics and play a similar role: they give rise…
Canonical variational completion and 4D Gauss-Bonnet gravity
Manuel Hohmann, Christian Pfeifer, Nicoleta Voicu
Recently, a proposal to obtain a finite contribution of second derivative order to the gravitational field equations in \(D = 4\) dimensions from a renormalized Gauss-Bonnet term i…
Inequalities from Lorentz-Finsler norms
Nicusor Minculete, Christian Pfeifer, Nicoleta Voicu
We show that Lorentz-Finsler geometry offers a powerful tool in obtaining inequalities. With this aim, we first point out that a series of famous inequalities such as: the (weighte…
The kinetic gas universe
Manuel Hohmann, Christian Pfeifer, Nicoleta Voicu
A description of many-particle systems, which is more fundamental than the fluid approach, is to consider them as a kinetic gas. In this approach the dynamical variable in which th…
On the non metrizability of Berwald Finsler spacetimes
Andrea Fuster, Sjors Heefer, Christian Pfeifer +1
We investigate whether Szabo's metrizability theorem can be extended to Finsler spaces of indefinite signature. For smooth, positive definite Finsler metrics, this important theore…
Cosmological Finsler Spacetimes
Manuel Hohmann, Christian Pfeifer, Nicoleta Voicu
Applying the cosmological principle to Finsler spacetimes, we identify the Lie Algebra of symmetry generators of spatially homogeneous and isotropic Finsler geometries, thus genera…
Relativistic kinetic gases as direct sources of gravity
Manuel Hohmann, Christian Pfeifer, Nicoleta Voicu
We propose a new model for the description of a gravitating multi particle system, viewed as a kinetic gas. The properties of the, colliding or non-colliding, particles are encoded…
Finsler gravity action from variational completion
Manuel Hohmann, Christian Pfeifer, Nicoleta Voicu
In the attempts to apply Finsler geometry to construct an extension of general relativity, the question about a suitable generalization of the Einstein equations is still under deb…
Conformal maps between pseudo-Finsler spaces
Nicoleta Voicu
The paper aims to initiate a systematic study of conformal mappings between Finsler spacetimes and, more generally, between pseudo-Finsler spaces. This is done by extending several…
Energy-momentum tensors in classical field theories - a modern perspective
Nicoleta Voicu
The paper presents a general geometric approach to energy-momentum tensors in Lagrangian field theories, based on a Hilbert-type definition. The approach is consistent with the one…
Volume forms for time orientable Finsler spacetimes
Nicoleta Voicu
The paper proposes extensions of the usual notions of Finslerian volume to time orientable Finsler spacetime manifolds. The basic idea is to replace, in the classical Busemann-Haus…
A volume element on time orientable Finslerian spacetimes
Nicoleta Voicu
The paper proposes a notion of volume element for Finsler spaces with metrics of Lorentzian signature, equipped with a time orientation. This notion is based on a slight modificati…
Canonical variational completion of differential equations
Nicoleta Voicu, Demeter Krupka
Given a non-variational system of differential equations, the simplest way of turning it into a variational one is by adding a correction term. In the paper, we propose a way of ob…