Related papers: Influence of Strings with Axionic Content on the P…
We have studied numerically the evolution and decay of axion strings. These global defects decay mainly by axion emission and thus contribute to the cosmological axion density. The relative importance of this source relative to misalignment…
Rotation angle of the plane of polarization of the distant galactic radio waves has been estimated in a string inspired axion-dilaton background. It is found that the axion,dual to the field strength of the second rank antisymmetric…
We explore the cosmological consequences of the superconductivity of QCD axion strings. Axion strings can support a sizeable chiral electric current and charge, which alters their early universe dynamics. Shrinking axion string loops can…
We discuss key aspects of the nature of radiation from global strings and its impact on the relic axion density. Using a simple model we demonstrate the dependence on the spectrum of radiation emitted by strings. We then study the radiation…
Cosmological evolution of axionic strings is investigated by numerically solving field equations of a complex scalar field in 3+1 dimensions. It is shown that the global strings relax to the scaling solution with a significantly smaller…
We describe different electroweak strings with axionic content, including non-topological configurations calculated numerically, and show their possible influence on baryogenesis indicating that they may constitute a mechanism competitive…
Low energy string theory predicts the existence of an axion field which can lead to cosmic birefringence. We solve the electromagnetic wave equations in the presence of such an axion and a dilaton field in order to determine their effect on…
This paper revisits the problem of the string decay contribution to the axion cosmological energy density. We show that this contribution is proportional to the average relative increase when axion strings decay of a certain quantity…
Axions have for some time been considered a plausible candidate for dark matter. They can be produced through misalignment, but it has been argued that when inflation occurs before a Peccei-Quinn transition, appreciable production can…
We investigate the effect of axions on the polarization of electromagnetic waves as they propagate through astronomical distances. We analyze the change in the dispersion of the electromagnetic wave due to its mixing with axions. We find…
We report that axions and photons exhibit instability in the presence of cosmic strings that are carrying magnetic flux in their core. The strength of the instability is determined by the symmetry breaking scale of the cosmic string theory.…
We study axion strings of hyperlight axions coupled to photons. Hyperlight axions -- axions lighter than Hubble at recombination -- are a generic prediction of the string axiverse. These axions strings produce a distinct quantized…
Axion-like fields can have a strong impact on non-Abelian strings. I discuss axion connection to such strings and its implications in two cases: (i) axion localized on the strings, and (ii) axions propagating in the four-dimensional bulk.…
In the wide variety of axion cosmologies in which axion strings form, their radiative decay is the dominant mechanism for the production of axions, imposing a tight constraint on the axion mass. Here, we focus on the mechanism by which…
If the QCD axion solves the strong CP problem then light axion-like-particles (ALPs) are expected to be ubiquitous in string theory - the string axiverse. Such ALPs can be the QCD axion and constitute dark matter (DM) or radiation,…
The presence of axion strings in the Universe after recombination can leave an imprint on the polarization pattern of the cosmic microwave background radiation through the phenomenon of axion-string-induced birefringence via the hyperlight…
When axionic strings carry a global charge, domain walls bounded by such strings may not be allowed to decay completely. This happens in particular in some models where a composite axion-like particle is the pseudo-Nambu-Goldstone boson of…
We study Goldstone boson (or axion) radiation from global $U(1)$-strings making direct quantitative comparisons between numerical scalar field theory simulations and linearized analytic calculations in the dual antisymmetric tensor…
The decay of non-topological electroweak strings formed during the electroweak phase transition in the early universe may leave an observable imprint in the universe today. Such strings can naturally seed primordial magnetic fields.…
We study the production of cosmological axions in the standard scenario in which a global string network forms at the Peccei-Quinn phase transition. We make detailed calculations of the axions produced by string loops (a previously…