Related papers: Resonant Photon-Axion Mixing Driven by Dark Matter…
We study the electromagnetic wave propagation in the joint dilaton field and axion field. Dilaton field induces amplification/attenuation in the propagation while axion field induces polarization rotation. The amplification/attenuation…
Time dependent magnetic fields can be sourced by spinning neutron stars, orbiting binaries and merging neutron stars. We consider electromagnetic radiation from axion condensates in the background of an alternating magnetic field. We find…
Photons propagating in an external magnetic field may oscillate into axions or axion-like particles (ALPs). Such oscillations will lead to characteristic features in the energy spectrum of high-energy photons from astrophysical sources that…
We investigate the production of photons from coherently oscillating, spatially localized clumps of axionic fields (oscillons and axion stars) in the presence of external electromagnetic fields. We delineate different qualitative behaviour…
The axion, as a leading dark matter candidate, is the target of many ongoing and proposed experimental searches based on its coupling to photons. Ultralight axions that couple to photons can also cause polarization rotation of light, which…
The axion is particularly well motivated candidate for the dark matter comprising most of the mass of our visible Universe, leading to worldwide experimental and observational efforts towards its discovery. As is well known, resonant…
It is widely believed that axions are ubiquitous in string theory and could be the dark matter. The peculiar features of the axion dark matter are coherent oscillations and a coupling to the electromagnetic field through the Chern-Simons…
Recently it has been suggested that dark radiation in the form of axions produced during the decay of string theory moduli fields could be responsible for the soft x-ray excess in galaxy clusters. These soft X-ray photons come about due to…
We investigate axion-photon conversion in stochastic magnetic fields, focusing on the evolution of the photon intensity and polarizations induced by conversion into axions. Assuming Gaussian magnetic fields characterized by the power…
We show that the magnetic component of the photon field produced by dark matter axions via the two-photon coupling mechanism in a Sikivie Haloscope is an important parameter passed over in previous analysis and experiments. The interaction…
We solve the general problem of mixing of electromagnetic and scalar or pseudoscalar fields coupled by axion-type interactions ${\cal L}_{int} =g_{\phi} \phi \epsilon_{\mu \nu \a \b}F^{\mu \nu}F^{\a \b} $. The problem depends on several…
Electromagnetic waves in a dynamical axion background exhibit superluminal group velocities at high frequencies and instabilities at low frequencies, altering how photons propagate through space. Local disturbances propagate causally, but…
We study the evolution of photon polarization during the photon-axion conversion process with focusing on the magnetic field configuration dependence. Most previous studies have been carried out in a conventional model where a network of…
In this thesis, we re-assess some aspects of axionic electrodynamics by coupling non-linear electromagnetic effects to axion physics. We present a number of motivations to justify the coupling of the axion to the photon in terms of a…
Using the non-equilibrium quantum field theory, photon production from the coherently oscillating axion field in a flat Robertson-Walker cosmology is re-examined. First neglecting the Debye screening of the baryon plasma to photons, we find…
Axion-photon conversion at dielectric interfaces, immersed in a near-homogeneous magnetic field, is the basis for the dielectric haloscope method to search for axion dark matter. In analogy to transition radiation, this process is possible…
Axions seem ubiquitous in string theories and some of them may be produced non-thermally by heavy scalar decays, contributing to dark radiation. We study various cosmological effects of photons produced from the axionic dark radiation…
Radiation propagating over cosmological distances can probe light weakly interacting pseudoscalar (or scalar) particles. The existence of a spin-0 field changes the dynamical symmetries of electrodynamics. It predicts spontaneous generation…
In the presence of a magnetic field, axions can convert into photons and vice versa. The phenomenology of the conversion is captured by a system of two coupled Klein-Gordon equations, which, assuming that the axion is relativistic, is…
A portion of light scalar dark matter, especially axions, may organize into gravitationally bound clumps (stars) and be present in large number in the galaxy today. It is therefore of utmost interest to determine if there are novel…