相关论文: "Faster Than Light" Photons in Dilaton Black Hole …
Photons propagating in curved spacetime may, depending on their direction and polarisation, have velocities exceeding the ``speed of light'' c. This phenomenon arises through vacuum polarisation in QED and is a tidal gravitational effect…
A number of general issues relating to superluminal photon propagation in gravitational fields are explored. The possibility of superluminal, yet causal, photon propagation arises because of Equivalence Principle violating interactions…
The effective action for QED in curved spacetime includes equivalence principle violating interactions between the electromagnetic field and the spacetime curvature. These interactions admit the possibility of superluminal yet causal photon…
In this study, we examine the phenomenon of photon axion conversion occurring in the spacetime surrounding a black hole. Specifically, we focus on the potential existence of a magnetic field around the supermassive black hole M87*, which…
Advancements of very long baseline interferometry (VLBI) have facilitated unprecedented probing of superradiant phenomena in the vicinities of supermassive black holes (SMBHs), establishing an ideal laboratory to detect ultralight bosons…
We study the influence of the tidal charge parameter of the braneworld models onto some optical phenomena in rotating black hole spacetimes. The escape photon cones are determined for special families of locally non-rotating, circular…
Strong gravitational lensing occurs when photons pass through the vicinity of a black hole. We investigate this phenomenon in the context of a gravitational-wave event, specifically when a black hole is settling into its final state. The…
Experiments done in the early 1990's produced a surprising result: that single photons pass through a photonic tunnel barrier with a group velocity faster than the vacuum speed of light. Subsequent experiments with classical pulses have…
The radial motion of photons emitted near the horizon of a black hole that evaporates at a steady rate is examined. The space-time of the black hole is generated using non-orthogonal coordinates. It is shown that some photons that are…
The spacetime satisfying the flat curve condition for galaxies is shown to be the zero mass limit of the dilaton blackhole with an exponential potential. We derive the geodesic equations and by studying rotational curves and light…
We investigate photon-axion conversion in the vicinity of rotating Kerr black holes where strong gravity traps photons on near-circular trajectories, effectively enhancing the path length. We explore the observable signatures of such a…
We model the light-curves from radiation-driven clouds near an accreting black hole. Taking into account the multiple images due to strong gravitational lensing, we find that sharp spikes can significantly enhance the observed flux.…
The motion of photons around black holes determines the shape of shadow and match the ringdown properties of a perturbed black hole. Observations of shadows and ringdown waveforms will reveal the nature of black holes. In this paper, we…
Relations between photon orbits and thermodynamical phase transitions are explored in Born-Infeld-dilaton-AdS black hole. The coupling between the electromagnetic field and the dialton field is chosen such that the full phase diagram…
Gravitational tidal forces acting on the virtual e+ e- cloud surrounding a photon endow spacetime with a non-trivial refractive index. This has remarkable properties unique to gravitational theories including superluminal low-frequency…
The photon sphere defines the unstable circular orbit of photons in a black hole spacetime. Photons emitted by a source located inside the photon sphere can be gravitationally lensed by the black hole and have time delays when reaching the…
We investigate the escape probabilities of the photons near the horizon of the Kerr-Sen black hole. We find that the escape probabilities of the photons are nonzero in the event horizon limit of the extreme Kerr-Sen black hole if the light…
The one-loop effective action for QED in curved spacetime contains equivalence principle violating interactions between the electromagnetic field and the spacetime curvature. These interactions lead to the dependence of photon velocity on…
The influence of radiative corrections on the photon propagation in a gravitational background is investigated without the low-frequency approximation $\omega \ll m$. The conclusion is made in this way that the velocity of light can exceed…
Recently, various types of regular black hole model are reintroduced as the solution of the Einstein equations coupled with nonlinear electrodynamics (NED). In NED, it is known that photons do not propagate along the null geodesics of the…