I will discuss how the Abelian part of the electroweak anomaly can influence the generation of lepton asymmetry of the Universe and its impact on dark matter sterile neutrino.
In this talk I will review the motivation behind the idea that the cosmic magnetic fields observed today were originated in some dynamics that occurred during inflation. I will then discuss the pros and cons of some of the most popular among these scenarios of inflationary magnetogenesis, with a particular focus on the role that might be played, in this context, by axionic degrees of freedom
One approach to exploring the dynamical properties of systems is to use computer simulations, and these can take many different forms depending on the energy scales and length scales of interest. In this talk I shall give an overview of some techniques for real-time simulations of the underlying fields. This allows one to examine some of the microscopic processes underlying the development of...
We discuss a new scenario for early cosmology when the de Sitter phase emerges dynamically.
This genuine quantum effect occurs as a result of dynamics of the topologically nontrivial sectors in a strongly coupled QCD in an expanding universe.
We argue that the key element for this idea to work is the presence of nontrivial holonomy in strongly coupled gauge theories. The effect is...
We review "Lattice Cosmology" techniques as a method to solve non-linear dynamics of interactive fields in an expanding Universe. As a demonstration we apply these ideas to solve two different problems of early Universe cosmology: i) the non-linear dynamics of axion inflation when backreaction of the produced gauge field becomes relevant, and ii) gravitational wave emission from (global and...
To start with I summarize some key puzzles of cosmology to be clarified in the future. I then briefly sketch how to describe the geometry and the state of matter in the Universe after its inflationary era. The main part of my talk is devoted to describing possible mechanisms for the generation of primordial magnetic fields in the Universe. These mechanisms are based on the chiral magnetic...
Axion-like particles may play a key role in early universe cosmology. In this talk I discuss the dual production of gauge fields and fermions induced by axion-like particles, and its implications for magnetogenesis from axion inflation.
Pseudoscalar inflation with Chern-Simons coupling to U(1) gauge fields generates helical magnetic field during inflation. If this U(1) gauge field is the Standard Model U(1) hypergauge interaction, the baryon (or B+L) asymmetry is generated at the same time through the chiral anomaly in a way that the total chirality vanishes. We could expect that it explains the present Baryon Asymmetry of...
Motivated by our work on inflationary scenarios in presence of magnetic fields, we have focused on one of the puzzling features with which we have faced: the effect of magnetic fields on the particles’ interaction processes, which may be a relevant issue during inflation or in the subsequent stages of the Universe evolution. The importance of magnetic fields’ contribution comes from the fact...
I will review the numerical results that demonstrate efficient preheating of an axion-inflaton to photons and the prospects for magnetogenesis. I will also discuss possible correlated observables and possible connections to SM and BSM physics.
In this talk I shall discuss how magnetic fields generated during inflation can back-react on the inflaton perturbation spectrum. I shall first outline the problem and present the generic form of the equations which have to be solved. I shall then discuss the effects which have been neglected in previous work. I can also outline an example which will be discussed in detail by another speaker...
In the primordial plasma, at temperatures above the scale of electroweak symmetry breaking, the presence of chiral asymmetries is expected to induce the development of helical hypermagnetic fields through the phenomenon of chiral plasma instability. It results in magnetohydrodynamic turbulence due to the high conductivity and low viscosity and sources gravitational waves that survive in the...
The Schwinger effect is a non-perturbative phenomenon in QED in which an electric field stronger than a certain strength decays into charged particle pairs. In primordial magnetogenesis, especially in inflationary magnetogenesis, the Schwinger effect can drastically change the dynamics of the electromagnetic fields and significantly alter theoretical predictions. However, until recently this...
A cosmological magnetic field of nG strength on Mpc length scales could be the seed magnetic field needed to explain observed few microG large-scale galactic magnetic fields. I first briefly review the observational and theoretical motivations for such a seed field, two galactic magnetic field amplification models, and some non-inflationary seed field generation scenarios. I then discuss an...
I explore the speculation that a physical mechanism underlying primordial magnetogenesis could arise from the vorticity field in the quark-gluon plasma (QGP) phase of the early universe. This possibility is motivated by the recent discovery of giant rotating filaments connecting the cosmic web in the large scale structure (P. Wang et al., Possible observational evidence for cosmic filament...
First-Order Phase Transitions in the early universe can be an important source for a Stochastic Gravitational Wave Background (SGWB). All particle sectors can contribute to it: the scalar sector through quantum fluctuations and collision of true vacuum bubbles, the fermionic sector, usually considered within a fluid description, through fluid longitudinal perturbations leading, after bubble...
In this talk, I delve into the intricacies of primordial magnetogenesis during inflation, incorporating a thorough consideration of the dynamics of stochastic noises associated with electromagnetic perturbations. By deriving the Langevin and Fokker-Planck equations governing the evolution of electromagnetic fields, I achieve analytical solutions. Our investigation reveals that, although the...
I describe a new approach to renormalize physical quantities in curved space-time introducing a comoving infrared cut-off in defining the adiabatic counterpart of the physical quantity under consideration. This infrared cut-off is fundamental to avoid unphysical divergences that can be generated by a pathological behavior of the adiabatic subtraction extended to the infrared domain. Applying...
Primordial non-Gaussianities, though yet unobserved, remain an important observable since they can help differentiate various models of inflation. This necessitates a deep understanding of the various processes that could contribute to these non-Gaussianities, with inflationary magnetogenesis being one of them. Often, the spectrum and the bispectrum of the perturbations produced during...
The standard model of particles predicts the occurrence of a macroscopic quantum phenomenon named the chiral magnetic effect (CME) in plasmas with chiral, electrically charged particles. The CME implies an electric current along a magnetic field, which arises if there is an asymmetry in the chemical potentials of left- and right-handed fermions related to a chiral anomaly. This effect can be...
Faraday rotation of linearly polarized emission as light passes through the foreground magnetised medium is one of the powerful indirect probes of the large-scale magnetic fields (LSMFs). Rotation measure (RM) which quantifies the amount of the rotation of the polarisation plane has been used for reconstructing the magnetic field properties in the intracluster medium. In the recent years,...
Primordial magnetic fields (PMFs) can enhance matter power spectrum on small scales ($\lesssim$ Mpc) and still agree with bounds from cosmic microwave background (CMB) and Faraday rotation measurements. As modes on scales smaller than Mpc have already become non-linear today, constraints on PMFs from the impact on small-scale structures require dedicated cosmological simulations. Here, for the...
Primordial magnetic fields (PMFs) may explain observations of magnetic fields on extragalactic scales. They are most cleanly constrained by observations of details of the cosmic microwave background radiation (CMB). Their effects on cosmic recombination may even be at the heart of the resolution of the Hubble tension. Employing detailed MHD- and Monte-Carlo- simulations we present an analysis...
A stochastic primordial magnetic field (PMF), if present in the plasma prior to last scattering, would induce baryon inhomogeneities and speed up cosmic recombination. The consequently smaller sound horizon at last scattering, along with more subtle changes in recombination history, have a significant impact on the observed cosmic microwave background (CMB) temperature and polarization, and...
Perhaps the most significant challenge to the widely successful Lambda-CDM theory is the disagreement between late and early Universe measurements of the present day Hubble expansion rate (H0), referred to as the Hubble tension. One of the ways to resolve the Hubble tension is to modify the recombination history of the early universe. An intriguing proposal to realize this invokes primordial...
High-frequency gravitational waves (HFGWs), loosely defined as above kHz, could stem from new physics, e.g., light primordial black holes, beyond-Standard Model mechanisms. One approach to detect such HFGWs is via the inverse Gertsenshtein effect, where gravitons convert to photons in an external magnetic field. Since magnetic fields are ubiquitous in the universe, such graviton-photon...
Dynamos and astrophysical magnetic field (MF) evolution can be studied with numerical simulations.
There is an ongoing effort to implement cosmological MFs evolution in SWIFT code using smoothed particle hydrodynamics (SPH) for the first time. The code contains several implementations: solve direct induction equations or evolve vector potential. Having different implementations might help to...
The origin and evolution of cosmological magnetic fields not only remains a subject that is still unresolved, it also has the potential to serve as a test for current cosmological models. This talk focuses on investigating different magnetic field seeds and explores potential origins involving black holes with charge, amplification processes, and distribution mechanisms on large...
Recently, there has been a burgeoning interest in the exploration of intergalactic magnetic fields (IGMFs) through the use of multiple astrophysical messengers. In fact, this has prominently featured as a primary science case of gamma-ray and (ultra-high-energy) cosmic-ray observatories. While numerous studies have derived bounds on IGMFs, many of these results have been obtained under...
In this contribution, we introduce CRPropa 3.2, a Monte Carlo framework revolutionizing the simulation of (ultra-)high-energy particle propagation in the Universe. Encompassing cosmic rays, gamma rays, electrons, and neutrinos across a vast energy spectrum, from ZeV to GeV for gamma rays and electrons, and TeV for cosmic rays and neutrinos, CRPropa 3.2 represents a significant leap towards a...
Magnetic fields in galaxies and galaxy clusters are believed to be the result of the amplification of seed fields during structure formation. However, the origin of this intergalactic magnetic field (IGMF) remains unknown. Observations of high-energy gamma rays from distant sources offer an indirect probe of the IGMF. Gamma-rays interact with the extragalactic background light to produce...
LiteBIRD will map the Cosmic Microwave Background polarization on the whole sky with unprecedented accuracy, opening a whole new world of opportunities in cosmology. One of these is the study of primordial magnetism. In particular, the combination of the many signatures in CMB polarization of primordial magnetic fields and the sensitivity and cleanness of LiteBIRD data will enable the study...
I will show how the development of new simulations, jointly with the latest extragalactic radio surveys are giving us a deep and new view of cosmic magnetism on scales never probed so far. Jointly with other probes from different wavelengths, they have started producing seemingly consistent constraints on the presence of very diffuse magnetic fields on the largest scales in the Universe,...
Precious information about the history of cosmological magnetic fields comes from their observation in the large scale structure of the Universe. Diffuse synchrotron emission represents a powerful tool to constrain the strength and geometry of the magnetic fields in clusters and in filaments of the cosmic web. A complementary probe is the Faraday effect on the signal of background radio...
In this talk I’ll review recent developments in the measurements of intergalactic magnetic fields in the voids of large scale structure with gamma-ray telescopes and by ultra-high energy cosmic ray detectors.
Weak relic magnetic fields produced in the early Universe can be probed through their influence on electromagnetic cascades in the relatively pristine environment of cosmic voids. Such electromagnetic cascades are initiated by powerful blazars and lead to gamma-ray spectra from GeV to TeV energies whose spectrum at Earth that are sensitive to cosmic magnetic fields, but also to pair beam...
Galaxies are known to be permeated by large-scale magnetic fields with energy densities comparable to the turbulent and thermal energy densities of the interstellar medium. A good knowledge of the global structure of these fields is important to understand their origin and to infer their effect on galactic dynamics and the propagation of charged particles in galaxies. In this talk I will...
Ultra-high-energy cosmic rays (UHECRs) get deflected by extragalactic magnetic fields (EGMFs) when they propagate from their sources to Earth. The spread of UHECRs around their original source position provides a measure for the strength of the EGMFs in between the UHECR sources and Earth. Furthermore, the density of UHECR sources plays an essential role in determining the relative...
Using the stochastic formalism, we study the helical magnetic fields during an inflationary period, which is the result of the tachyonic growth of the gauge field. By considering the stochastic effects to the field’s perturbations, we obtain the corresponding Langevin equations as well as the Fokker-Planck partial differential equation in the presence of the electric conductivity and then,...
In galaxy clusters, the seed magnetic field of primordial or astrophysical origin is thought to be amplified through Biermann battery mechanism or small-scale dynamo action to μG-strength magnetic fields as estimated through Faraday Rotation measurements. Shock waves driven by merger events can continuously source self-generated magnetic fields. Diffuse non-thermal emission and polarization...
We study the effects of galaxy formation physics on the magnetization of the intergalactic medium (IGM) using the IllustrisTNG simulations. We demonstrate that large-scale regions affected by the outflows from galaxies and clusters contain magnetic fields that are several orders of magnitude stronger than in unaffected regions with the same electron density. Moreover, like magnetic fields...
