Optical properties of dynamical axion backgrounds. (arXiv:1911.10221v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+McDonald_J/0/1/0/all/0/1">Jamie I.McDonald</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Ventura_L/0/1/0/all/0/1">Luís B. Ventura</a>
We discuss spectral distortions, time delays and refraction of light in an
axion or axion-plasma background. This involves solving the full set of
geodesic equations associated to the system of Hamiltonian optics, allowing us
to self-consistently take into account the evolution of the momentum, frequency
and position of photons. We support our arguments with analytic approximations
and full numerical solutions. Remarkably, the introduction of a plasma enhances
the sensitivity to axion-induced birefringence, allowing these effects to occur
at linear order in the axion-photon coupling even when the axion background is
not present at either the emission or detection points. This suggests a general
enhancement of axion-induced birefringence when the background refractive index
is different from one.
We discuss spectral distortions, time delays and refraction of light in an
axion or axion-plasma background. This involves solving the full set of
geodesic equations associated to the system of Hamiltonian optics, allowing us
to self-consistently take into account the evolution of the momentum, frequency
and position of photons. We support our arguments with analytic approximations
and full numerical solutions. Remarkably, the introduction of a plasma enhances
the sensitivity to axion-induced birefringence, allowing these effects to occur
at linear order in the axion-photon coupling even when the axion background is
not present at either the emission or detection points. This suggests a general
enhancement of axion-induced birefringence when the background refractive index
is different from one.
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