arXiv subjects

Renato Klippert

Publications and source records attributed to Renato Klippert.

5 recordsLinked to original sources

arXiv2026

Gravitational Effects on Light Propagation in Linear Magnetoelectrics and Plasmas

A covariant formalism for electromagnetism is used to investigate the effects of light propagation within certain material systems under the influence of a background gravitational field. Specifically, dielectric media described by linear constitutive relations, as well as magnetized plasma media, such as the magnetosphere of neutron stars, are examined. Estimates for detecting gravitational effects through precise refractive index measurements within these scenarios are provided.

physics.gen-ph↗

arXiv2021

Spherical symmetry and nonmagnetic dielectrics in analogue models of gravity

Nonmagnetic and spherically symmetric dielectric material media are investigated in their generality as analogue models, in the domains of geometrical optics, for a few relevant static and spherically symmetric solutions of gravitation, including black holes and wormholes. Typic and desirable gravitational features are systematically linked to the nonlinear properties of the phenomenological dielectric permittivity of the medium. From this, the limitations of such analogies are explored in terms of their corresponding geometric flexibility, dielectric configurations and causal structure.

gr-qc↗

arXiv2017

Controlled opacity in a class of nonlinear dielectric media

Motivated by new technologies for designing and tailoring metamaterials, we seek properties for certain classes of nonlinear optical materials that allow room for a reversibly controlled opacity-to-transparency phase transition through the application of external electromagnetic fields. We examine some mathematically simple models for the dielectric parameters of the medium and compute the relevant geometric quantities that describe the speed and polarization of light rays.

physics.optics↗

arXiv2017

Bianchi-I cosmology from causal thermodynamics

We investigate diagonal Bianchi-I spacetimes in the presence of viscous fluids by using the shear and the anisotropic pressure components as the basic variables, where the viscosity is driven by the (second-order) causal thermodynamics. A few exact solutions are presented, among which we mention the anisotropic versions of de Sitter/anti-de Sitter geometries as well as an asymptotically isotropic spacetime presenting an effective constant cosmic acceleration without any cosmological constant. The qualitative analysis of the solutions for barotropic fluids with linear equations of state suggests that the behaviour is quite general.

gr-qc↗

arXiv2015

Multirefringence phenomena in nonlinear electrodynamics

Wave propagation in nonlinear theories of the electromagnetism described by Lagrangian densities dependent upon its two local invariants L(F, G) is revisited. On the light of the recent findings in metamaterials, it is here shown that trirefringence is also a possible phenomenon to occur in the realm of such nonlinear theories. A specific model exhibiting this effect is investigated both in terms of phase and group velocities. It is claimed that wave propagation in some well known nonlinear models for spin-one fields, like QED and QCD in certain regimes, may exhibit trirefringence.

physics.optics↗