Speaker
Description
Geometric optics effectively describes electromagnetic wave propagation when the wavelength is much smaller than the characteristic length scale of the medium, making wave phenomena like diffraction negligible. As a result, light propagation in a vacuum is typically modelled by rays that follow null geodesics. However, general relativity predicts that polarization-dependent deviations from these geodesics occur in an inhomogeneous gravitational field. We evaluate the corrections in the far-horizon limit in Schwarzschild and derive the scaling behaviour of the physical parameters characterizing the trajectories. We find that the scaling behaviour remains accurate relatively close to the Schwarzschild horizon. Using the scaling behaviour, we assess the significance of the birefringence effect in various astrophysical observations. We find that the effect changes the light trajectories, but not substantially enough (in the far-horizon limit) to be measured with current instruments. The effect may be detectable in the near future. We also present a Lagrangian that reproduces the equations of motion of the polarised ray. We use the Lagrangian to efficiently generate constants of motion, which can significantly simplify the calculations.
| I am the presenting author | Yes |
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