Large-Scale Magnetic Fields, Dark Energy and QCD

Abstract

Cosmological magnetic fields are being observed with ever increasing correlation lengths, possibly reaching the size of superclusters, therefore disfavouring the conventional picture of generation through primordial seeds later amplified by galaxy-bound dynamo mechanisms. In this paper we put forward a fundamentally different approach that links such large-scale magnetic fields to the cosmological vacuum energy. In our scenario the dark energy is due to the Veneziano ghost (which solves the $U(1{)}_A$ problem in QCD). The Veneziano ghost couples through the triangle anomaly to the electromagnetic field with a constant which is unambiguously fixed in the standard model. While this interaction does not produce any physical effects in Minkowski space, it triggers the generation of a magnetic field in an expanding universe at every epoch. The induced energy of the magnetic field is thus proportional to cosmological vacuum energy: ${\rho }_{EM}\simeq B^2\simeq (\frac{\alpha }{4\pi }{)}^2{\rho }_{DE}$, ${\rho }_{DE}$ hence acting as a source for the magnetic energy ${\rho }_{EM}$. The corresponding numerical estimate leads to a magnitude in the nG range. There are two unique and distinctive predictions of our proposal: an uninterrupted active generation of Hubble size correlated magnetic fields throughout the evolution of the universe; the presence of parity violation on the enormous scales $1/H$, which apparently has been already observed in CMB. These predictions are entirely rooted into the standard model of particle physics.

jhep style, 22 pages, v2 with updated estimates and extended discussion on parity violation, v3 as published (references updated)

References in corpus (22)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Evidence for strong extragalactic magnetic fields from Fermi observations of TeV blazars
• Primordial Nucleosynthesis in the Precision Cosmology Era
• The stochastic gravitational wave background from turbulence and magnetic fields generated by a first-order phase transition
• Strong magnetic fields in normal galaxies at high redshifts
• Magnetic fields from inflation?
• Gravitational waves from stochastic relativistic sources: primordial turbulence and magnetic fields
• A Global Probe of Cosmic Magnetic Fields to High Redshifts
• The cosmological constant from the ghost. A toy model
• The QCD nature of Dark Energy
• Anomalous parity asymmetry of the Wilkinson Microwave Anisotropy Probe power spectrum data at low multipoles
• Anomalous parity asymmetry of WMAP power spectrum data at low multpoles: is it cosmological or systematics?
• Faraday rotation, stochastic magnetic fields and CMB maps
• Can the observed large scale magnetic fields be seeded by helical primordial fields?
• The Gauge Fields and Ghosts in Rindler Space
• The cosmological constant as a manifestation of the conformal anomaly?
• Spectral Dependence of CMB Polarization and Parity
• The polarization in the JVAS/CLASS flat-spectrum radio sources: II. A search for aligned radio polarizations
• Generalized CMB initial conditions with pre-equality magnetic fields
• Photon & Axion Oscillation In a Magnetized Medium: A Covariant Treatment
• A magnetized completion of the $\Lambda$CDM paradigm
• Magnetic fields in cosmology

Cited by in corpus (17)

• Dark Energy and QCD Ghost
• Evolution of Primordial Magnetic Fields from Phase Transitions
• Primordial magnetic field limits from cosmological data
• Can we observe the QCD phase transition-generated gravitational waves through pulsar timing arrays?
• The Gauge Fields and Ghosts in Rindler Space
• The evolution of primordial magnetic field since its generation
• Statistical Properties of Scale-Invariant Helical Magnetic Fields and Applications to Cosmology
• P and CP Violation and New Thermalization Scenario in Heavy Ion Collisions
• On inflating magnetic fields, and the backreactions thereof
• Evidence of isotropy at large-scale from polarizations of radio sources
• Cosmological-scale coherent orientations of quasar optical polarization vectors in the $Planck$ era Investigating the Galactic dust contamination scenario
• The Parity Odd Universe, Dark Energy and QCD
• Electroweak Instantons, Axions, and the Cosmological Constant
• A study of Dipolar Signal in distant Quasars with various observables
• Cosmological Ohm's law and dynamics of non-minimal electromagnetism
• A mechanism to explain Galaxy alignment over a range of scales
• Question Isotropy