Primordial Magnetic Fields
نویسنده
چکیده
Large scale magnetic fields represent a triple point where cosmology, highenergy physics and astrophysics meet for different but related purposes. After reviewing the implications of large scale magnetic fields in these different areas, the rôle of primordial magnetic fields is discussed in various physical processes occurring prior to the decoupling epoch with particular attention to the big bang nucleosynthesis (BBN) epoch and to the electroweak (EW) epoch. The generation of matter–antimatter isocurvature fluctuations, induced by hypermagnetic fields, is analyzed in light of a possible increase of extra-relativistic species at BBN. It is argued that stochastic GW backgrounds can be generated by hypermagnetic fields at the LISA frequency. The problem of the origin of large scale magnetic fields is also scrutinized.
منابع مشابه
Probing Primordial Magnetic Fields with the 21cm Fluctuations
Primordial magnetic fields possibly generated in the very early universe are one of the candidates for the origin of magnetic fields observed in many galaxies and galaxy clusters. After recombination, the dissipation process of the primordial magnetic fields increases the baryon temperature. The Lorentz force acts on the residual ions and electrons to generate density fluctuations. These effect...
متن کاملS-Z power spectrum produced by primordial magnetic fields
Primordial magnetic fields generated in the very early universe are one of the candidates for the origin of magnetic fields observed in galaxy clusters. After recombination, the Lorentz force acts on the residual ions and electrons to generate density fluctuations of baryons. Accordingly these fluctuations induce the early formation of dark halos which cause the Sunyaev-Zel’dovich (S-Z) effect ...
متن کاملMassive neutrinos and magnetic fields in the early universe
Primordial magnetic fields and massive neutrinos can leave an interesting signal in the CMB temperature and polarization. We perform a systematic analysis of general perturbations in the radiation-dominated universe, accounting for any primordial magnetic field and including leading-order effects of the neutrino mass. We show that massive neutrinos qualitatively change the large-scale perturbat...
متن کاملPrimordial magnetic fields from pseudo Goldstone bosons.
The existence of large-scale magnetic fields in galaxies is well established, but there is no accepted mechanism for generating a primordial field which could grow into what is observed today. We discuss a model which attempts to account for the necessary primordial field by invoking a pseudo-Goldstone boson coupled to electromagnetism. The evolution of this boson during inflation generates a m...
متن کاملThe Stability of Primordial Magnetic Fields Produced by Phase Transitions
Primordial magnetic fields seem to be a generic relic of phase transitions in the early universe. We consider a primordial electromagnetic field formed as a result of a second-order phase transition, and show that it is stable to thermal fluctuations in the period immediately following. We also show how such a field arises in first order phase transitions. In both cases there is a transitive el...
متن کاملPrimordial Magnetic Fields and Causality
We discuss the implications of causality on a primordial magnetic field. We show that the residual field on large scales is much more suppressed than usually assumed, and that a helical component is even more reduced. Due to this strong suppression, even maximal primordial fields generated at the electroweak phase transition can just marginally seed the fields in clusters but they cannot leave ...
متن کامل