scholarly journals Axion strings are superconducting

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Hajime Fukuda ◽  
Aneesh V. Manohar ◽  
Hitoshi Murayama ◽  
Ofri Telem
Keyword(s):  
Magnetic Field ◽  
Charge Density ◽  
Electric Current ◽  
Early Universe ◽  
Drag Force ◽  
Parameter Space ◽  
Electromagnetic Force ◽  
Large Current ◽  
Primordial Magnetic Field ◽  
Relic Abundance

Abstract We explore the cosmological consequences of the superconductivity of QCD axion strings. Axion strings can support a sizeable chiral electric current and charge density, which alters their early universe dynamics. We examine the possibility that shrinking axion string loops can become effectively stable remnants called vortons, supported by the repulsive electromagnetic force of the string current. We find that vortons in our scenario are generically unstable, and so do not pose a cosmological difficulty. Furthermore, if a primordial magnetic field (PMF) exists in the early universe, a large current is induced on axion strings, creating a significant drag force from interactions with the surrounding plasma. As a result, the strings are slowed down, which leads to an orders of magnitude enhancement in the number of strings per Hubble volume. Finally, we study potential implications for the QCD axion relic abundance. The QCD axion window is shifted by orders of magnitude in some parts of our parameter space.

scholarly journals Electroweak axion string and superconductivity

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Yoshihiko Abe ◽  
Yu Hamada ◽  
Koichi Yoshioka
Keyword(s):  
Electric Current ◽  
Early Universe ◽  
Parameter Space ◽  
Cosmic String ◽  
Topological Charge ◽  
Attractive Force ◽  
Electroweak Scale ◽  
Large Current

Abstract We study the axion strings with the electroweak gauge flux in the DFSZ axion model and show that these strings, called the electroweak axion strings, can exhibit superconductivity without fermionic zeromodes. We construct three types of electroweak axion string solutions. Among them, the string with W-flux can be lightest in some parameter space, which leads to a stable superconducting cosmic string. We also show that a large electric current can flow along the string due to the Peccei-Quinn scale much higher than the electroweak scale. This large current induces a net attractive force between the axion strings with the same topological charge, which opens a novel possibility that the axion strings form Y-junctions in the early universe.

EFFECTS OF PRIMORDIAL MAGNETIC FIELD ON EARLY UNIVERSE

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1695-1706 ◽  
Author(s):  
DAI G. YAMAZAKI ◽  
KIYOTOMO ICHIKI ◽  
KAJINO TOSHITAKA ◽  
GRANT J. MATHEWS
Keyword(s):  
Magnetic Field ◽  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Early Universe ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Microwave Background ◽  
Primordial Magnetic Field

The existence of a primordial magnetic field (PMF) would affect both the temperature and polarization anisotropies of the cosmic microwave background (CMB) and the formation of the large scale structure(LSS). It also provides a plausible explanation for the disparity between observations and theoretical fits to the CMB power spectrum and the LSS. Here we report on calculations of not only the numerical power spectrum of the PMF, but also the correlations between the PMF power spectrum and the primary curvature perturbations.

On the self-similar exact MHD jet solution

2014 ◽  
Vol 746 ◽  
pp. 5-30 ◽  
Author(s):  
R. I. Mullyadzhanov ◽  
N. I. Yavorsky
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Reverse Flow ◽  
Pitchfork Bifurcation ◽  
Poloidal Magnetic Field ◽  
Boundary Layer Equations ◽  
Large Current ◽  
Current Confinement ◽  
Self Similar ◽  
The Wire

AbstractWe consider an axisymmetric steady flow of a viscous incompressible conducting fluid. The flow is induced by the point source of momentum and point electrode discharging the electric current, both of which are located at the end of a thin semi-infinite insulated wire. We seek the solution in the conical self-similar class where the velocity and magnetic field decrease as the inverse distance from the origin. The solution is obtained for various parameters of the problem, namely the Reynolds number, dimensionless electric current and Batchelor number (magnetic Prandtl number). A reverse flow along the wire occurs, leading to the confinement of the current density in the direction of the jet. If the Batchelor number is zero, the solution obtains a singularity at finite values of the current leading to its breakdown; otherwise, the solution exists at all parameter values. We derive the boundary-layer equations near the wire for large current values and obtain the solution. The pitchfork bifurcation with non-zero poloidal magnetic field occurs and causes the rotation of the fluid, which eliminates the current confinement effect. We describe the conditions when the solution for the swirling jet exists. The connection of this problem to the ones considered previously is discussed.

scholarly journals Chiral asymmetry during the EWPT from CP-violating scattering off bubble walls

2018 ◽  
Vol 172 ◽  
pp. 08001
Author(s):  
Alejandro Ayala ◽  
L. A. Hernández ◽  
Jordi Salinas
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Early Universe ◽  
Bubble Wall ◽  
First Order ◽  
Chiral Asymmetry

We compute a net electric current during a first order EWPT arising from the asymmetric propagation of fermion chiral modes due to a CP-violating interaction with the Higgs. The interaction is quantified in terms of a CP-violating phase in the bubble wall that separate both phases. We comment on the possibility of this current to generate a seed magnetic field and its implications for primordial magnetogenesis in the early Universe.

scholarly journals EDGES signal in the presence of magnetic fields

2020 ◽  
Vol 497 (1) ◽  
pp. L35-L39 ◽  
Author(s):  
Pravin Kumar Natwariya ◽  
Jitesh R Bhatt
Keyword(s):  
Magnetic Field ◽  
Dark Matter ◽  
Magnetic Fields ◽  
Early Universe ◽  
High Energy ◽  
New Physics ◽  
Gas Temperature ◽  
Primordial Magnetic Field ◽  
Energy Processes ◽  
Lower Limits

ABSTRACT We study the 21-cm differential brightness temperature in the presence of primordial helical magnetic fields for redshift z = 10–30. We argue that the α-effect that sets in at earlier time can be helpful in lowering the gas temperature to 3.2 K at z = 17. This effect can arise in the early Universe due to some parity-violating high-energy processes. Using the EDGES (Experiment to Detect the Global Epoch of Reionization Signature) results, we find the upper and lower limits on the primordial magnetic field to be 6 × 10−3 and 5 × 10−4 nG, respectively. We also discuss the effect of Ly α background on the bounds. Our results do not require any new physics in terms of dark matter.

scholarly journals The ScotoSinglet Model: a scalar singlet extension of the Scotogenic Model

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Ankit Beniwal ◽  
Juan Herrero-García ◽  
Nicholas Leerdam ◽  
Martin White ◽  
Anthony G. Williams
Keyword(s):  
Parameter Space ◽  
Direct Detection ◽  
Neutrino Masses ◽  
Minimal Models ◽  
Flavour Violation ◽  
The One ◽  
Relic Abundance ◽  
Electroweak Precision ◽  
Scalar Singlet ◽  
Lepton Flavour

Abstract The Scotogenic Model is one of the most minimal models to account for both neutrino masses and dark matter (DM). In this model, neutrino masses are generated at the one-loop level, and in principle, both the lightest fermion singlet and the lightest neutral component of the scalar doublet can be viable DM candidates. However, the correct DM relic abundance can only be obtained in somewhat small regions of the parameter space, as there are strong constraints stemming from lepton flavour violation, neutrino masses, electroweak precision tests and direct detection. For the case of scalar DM, a sufficiently large lepton-number-violating coupling is required, whereas for fermionic DM, coannihilations are typically necessary. In this work, we study how the new scalar singlet modifies the phenomenology of the Scotogenic Model, particularly in the case of scalar DM. We find that the new singlet modifies both the phenomenology of neutrino masses and scalar DM, and opens up a large portion of the parameter space of the original model.

scholarly journals The effect of simplifications of a numerical mesh on the results of electromagnetic analysis of the Nuclotron-type cable

2018 ◽  
Vol 177 ◽  
pp. 08004
Author(s):  
Łukasz Tomków
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Current Density ◽  
Electric Current Density ◽  
Electromagnetic Analysis ◽  
First Case ◽  
Single Region ◽  
The Magnetic Field

The model of a single Nuclotron-type cable is presented. The goal of this model is to assess the behaviour of the cable under different loads. Two meshes with different simplifications are applied. In the first case, the superconductor in the cable is modelled as single region. Second mesh considers individual strands of the cable. The significant differences between the distributions of the electric current density obtained with both models are observed. The magnetic field remains roughly similar.

scholarly journals Probing the reheating phase through primordial magnetic field and CMB

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Md Riajul Haque ◽  
Debaprasad Maity ◽  
Sourav Pal
Keyword(s):  
Magnetic Field ◽  
Primordial Magnetic Field
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