Electromagnetic waves in a wormhole geometry

Abstract

We investigate the propagation of electromagnetic waves through a static wormhole. It is shown that the problem can be reduced to a one dimensional Schrödinger-like equation with a barrier-type potential. Using numerical methods, we calculate the transmission coefficient as a function of the energy. We also discuss the polarization of the outgoing radiation due to this gravitational scattering.

From static to rotating to conformal static solutions: rotating imperfect fluid wormholes with(out) electric or magnetic field

“…Other suggested metrics [31] for generating rotating wormholes, used also in [50,60], failed to generate fluid wormholes [49]. Such metrics, where g φφ (r, θ)/g θθ (r, θ) ≡ sin 2 θ , cannot be brought into the form (13).…”

“…It has been shown that the source term for such generated rotating wormholes, found in [31], is not that of a fluid [49,50]. However, the elements of the proof given in [49] rely on the assumption that the fluid undergoes only a rotational motion about a fixed axis. So, it might still be possible to attach a fluid interpretation to the general metric generating rotating wormholes [31] (but not to the specific example of the Teo wormhole [31] as it violates the condition G r θ = 0) if (1) one considers, besides the rotational motion, a radial motion too, and (2) one imposes the condition G r θ = 0, which constrains the components of the Teo general rotating metric.…”

“…Had we imposed the same condition, we would have obtained, using (11), (16), and (17), T φ t = −a sin 2 θ(H + a 2 )( + p φ )/ρ 2 = 0 leading to p φ = − so that our fluid is no longer totally imperfect. More on conditions to have fluid solutions is found in [49][50][51].…”

Scattering of electromagnetic waves by static wormholes

“…In a given Cartesian coordinate frame with ds 2 = g µν dx µ dx ν , let us define H µν = √ −gF µν and employ the decompositions [9] F µν → (E, B),…”

“…Also, studying the propagation of different types of perturbations in wormhole geometries was initiated by Kar and Sahdev [8], and Kar et al, who studied the reflection and transmission of massive scalar waves in the presence of an ultrastatic wormhole. Moreover, propagation of electromagnetic waves through a static wormhole is investigated by Bergliaffa and Hibberd [9].…”