Related papers: Scaling properties of cosmological axion strings
We present an analytic model specifically designed to address the long standing issue of small scale structure on cosmic string networks. The model is derived from the microscopic string equations, together with a few motivated assumptions.…
We report on a study of axion string networks using fixed-grid simulations of up to $16384$ points per side. The length of string can be characterised in terms of standard dimensionless parameters $\zeta_\text{w}$ and $\zeta_\text{r}$, the…
The velocity-dependent `one-scale' model of Martins and Shellard is used to study the evolution of a cosmic string network (and the corresponding loop population) in open universes. It is shown that in this case there is no linear scaling…
We consider the evolution of current-carrying cosmic string networks described by the charge-velocity-dependent one scale (CVOS) model beyond the linear equation of state regime, specifically focusing on the Witten superconducting model. We…
Models with axion like particles (ALPs) often predict the formation of a string-domain wall network in the early universe. We study how such networks of defects appear in the context of string theory, and discuss the conditions for their…
In this work, we consider a network of cosmic strings to explain possible deviation from \Lambda CDM behaviour. We use different observational data to constrain the model and show that a small but non zero contribution from the string…
This paper is aimed at setting observational limits to the number of cosmic strings (Nambu-Goto, Abelian-Higgs, semilocal) and other topological defects (textures). Radio maps of CMB anisotropy, provided by the space mission Planck for…
Recently, a low-$z$ measurement of the Hubble constant, $H_0 = 73.04 \pm 1.04 {\rm ~km/s/Mpc}$, was reported by the SH0ES Team. The long-standing Hubble tension, i.e. the difference between the Hubble constant from the local measurements…
The quantum chromodynamics (QCD) axion may solve the strong CP problem and explain the dark matter (DM) abundance of our Universe. The axion was originally proposed to arise as the pseudo-Nambu Goldstone boson of global $\mathrm{U}(1)_{\rm…
We investigated domain wall networks as a possible candidate to explain the present accelerated expansion of the universe. We discuss various requirements that any stable lattice of frustrated walls must obey and propose a class of `ideal'…
Cosmic (super)strings offer promising ways to test ideas about the early universe and physics at high energies. While in field theory constructions their tension is usually assumed to be constant (or at most slowly-varying), this is often…
At early stages the dynamics of cosmic string networks is expected to be influenced by an excessive production of small loops at the scales of initial conditions l_{min}. To understand the late time behavior we propose a very simple…
Generic cosmological models in non-critical string theory have a time-dependent dilaton background at a late epoch. The cosmological deceleration parameter Q_0 is given by the square of the string coupling, g_s^2, up to a negative sign.…
It is shown that topologically stable cosmic strings can, in fact, appear to end or to break, even in theories without monopoles. This can occur whenever the spatial topology of the universe is nontrivial. For the case of Abelian-Higgs…
We develop a formalism for the quantization of topologically stable excitations in the 4-dimensional abelian lattice gauge theory. The excitations are global and local (Abrikosov-Nielsen-Olesen) strings and monopoles. The operators of…
Cosmic strings can arise in hidden sector models with a spontaneously broken Abelian symmetry group. We have studied the couplings of the Standard Model fields to these so-called dark strings in the companion paper. Here we survey the…
This paper is concerned with string cosmology and the dynamics of multiple scalar fields in potentials that can become negative, and their features as (Early) Dark Energy models. Our point of departure is the "String Axiverse", a scenario…
Scaling behavior of scale-free evolving networks arising in communications, citations, collaborations, etc. areas is studied. We derive universal scaling relations describing properties of such networks and indicate limits of their…
Cosmic strings, topological defects predicted by high-energy theories, may contribute to the late-time expansion of the Universe, effectively mimicking dynamical dark energy. We investigate four phenomenological extensions of the…
Brane inflation in superstring theory ends when branes collide, initiating the hot big bang. Cosmic superstrings are produced during the brane collision. The cosmic superstrings produced in a D3-brane-antibrane inflationary scenario have a…