Related papers: Distance-redshift from an optical metric that incl…
We show that Gordon's optical metric on a curved spacetime can be generalized to include absorption by allowing the metric to become complex. We demonstrate its use in the realm of geometrical optics by giving three simple examples. We use…
We review Gordon's optical metric and the transport equations for the amplitude and polarization of a geometrical optics wave traveling in a gravity field. We apply the theory to the FLRW cosmologies by associating a refraction index with…
We derive an expression for the luminosity distance as a function of redshift for a flat Robertson-Walker spacetime perturbed by arbitrary scalar perturbations possibly produced by a modified gravity theory with two different scalar…
According to general relativity, the frequency of electromagnetic radiation is altered by the expansion of the universe. This effect--commonly referred to as the cosmological redshift--is of utmost importance for observations in cosmology.…
The strongest evidence for dark energy comes presently from geometric techniques such as the supernova distance-redshift relation. By combining the measured expansion history with the Friedmann equation one determines the energy density and…
Many of the general-relativity-tests such as bending of light near a star and gravitational red/blue shift are explained without general-relativity and without Newtonian-approach. The author first casts doubts on both, the Newtonian and the…
We explore the nature of the classical propagation of light through media with strong frequency-dependent dispersion in the presence of a gravitational field. In the weak field limit, gravity causes a redshift of the optical frequency,…
Two approaches (micro- and macro- investigations) are used to determine the dimension dependences of the optical parameters of the nanometer-scale layers of materials. It is shown that both an index of refraction and coefficient of…
Reflection and refraction of light can be used to trap small dielectric particles in the geometrical optics regime. Absorption of light is usually neglected in theoretical calculations, but it is known that it occurs in the optical trapping…
It is known that a relative translational motion between the deflector and the observer affects gravitational lensing. In this paper, a lens equation is obtained to describe such effects on actual lensing observables. Results can be easily…
In a gravitational lensing system, the relative transverse velocities of the lens, source, and observer induce a frequency shift in the observed radiation. While this shift is typically negligible in most astrophysical contexts, strategies…
The first principles analysis of the radiation by an arbitrary source in a flat Friedmann-Robertson-Walker space-time is presented. The obtained analytical solution explicitly shows that the cosmological redshift is not of kinematic origin…
Significant absorption of radiation is usually accompanied by refraction. This is not the case for $\gamma$ rays travelling cosmic distances. We show that the real and imaginary parts of the refraction index are indeed commensurable, as…
We obtain a new expression of the Friedmann-Robertson-Walker metric, which is an analogue of a static chart of the de Sitter space-time. The reduced metric contains two functions, $M(T,R)$ and $\Psi(T,R)$, which are interpreted as,…
We study the behavior of light rays in perturbed Robertson-Walker cosmologies, calculating the redshift between an observer and the surface of last scattering to second order in the metric perturbation. At first order we recover the classic…
When dealing with highly accurate modeling of time and frequency transfers into arbitrarily moving dielectrics medium, it may be convenient to work with Gordon's optical spacetime metric rather than the usual physical spacetime metric.…
General Relativity describes the trajectories of light-rays through curved spacetime near a massive object. In addition to gravitational lensing, we include an absorbing dielectric medium given by a complex refractive index known as the…
We present a derivation of the cosmological distance-redshift relation up to second order in perturbation theory. In addition, we find the observed redshift and the lensing magnification to second order. We do not require that the density…
The distance-redshift relation plays an important role in cosmology. In the standard approach to cosmology it is assumed that this relation is the same as in the homogeneous universe. As the real universe is not homogeneous there are…
Gravitational waves from inspiraling compact binaries are known to be an excellent absolute distance indicator, yet it is unclear whether electromagnetic counterparts of these events are securely identified for measuring their redshifts,…