Lorentz-violating inflationary magnetogenesis

Campanelli, Leonardo

doi:10.1140/epjc/s10052-015-3510-x

Cited by 35 publications

(28 citation statements)

References 145 publications

(207 reference statements)

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“…One of the feasible ways to engender magnetic fields of appropriate strengths seems to be the introduction of a non-minimal coupling term in the action [21,22]. Magnetic fields generated through breaking the conformal invariance of the standard electromagnetic action, due to the presence of a non-minimal coupling term, and with a suitable choice of the parameters involved, have been shown to be of the pertinent amplitude and correlation length to be in concordance with the observations [19,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 75%

Enhancing the cross-correlations between magnetic fields and scalar perturbations through parity violation

Chowdhury

Sriramkumar

Kamionkowski

2018

J. Cosmol. Astropart. Phys.

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One often resorts to a non-minimal coupling of the electromagnetic field in order to generate magnetic fields during inflation. The coupling is expected to depend on a scalar field, possibly the same as the one driving inflation. At the level of three-point functions, such a coupling leads to a non-trivial cross-correlation between the perturbation in the scalar field and the magnetic field. This cross-correlation has been evaluated analytically earlier for the case of non-helical electromagnetic fields. In this work, we numerically compute the cross-correlation for helical magnetic fields. Non-Gaussianities are often generated as modes leave the Hubble radius. The helical electromagnetic modes evolve strongly (when compared to the non-helical case) around Hubble exit and one type of polarization is strongly amplified immediately after Hubble exit. We find that helicity considerably boosts the amplitude of the dimensionless non-Gaussianity parameter that characterizes the amplitude and shape of the cross-correlation between the perturbations in the scalar field and the magnetic field. We discuss the implications of the enhancement in the non-Gaussianity parameter due to parity violation.

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Section: Introductionmentioning

confidence: 75%

Enhancing the cross-correlations between magnetic fields and scalar perturbations through parity violation

Chowdhury

Sriramkumar

Kamionkowski

2018

J. Cosmol. Astropart. Phys.

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“…It is interesting to note that in [11] we derived a dynamo flat space-time torsioned extension of GR dynamo equation based on the Lagrangian, or action, for the parity-violating curvature. In the case of the coupling of an axion field to the space-time curvature the term 1 2 μναβ R μνσ τ R αβ σ τ , where R αβνσ is the Riemann tensor, should be included in the analysis of the early universe, which was neglected in the paper of Boyarsky et al [15]. These are exactly the part of parity violation we consider to derive the dynamo equation in the torsion case.…”

Section: Discussionmentioning

confidence: 99%

“…The second feature is that here we are using a backreaction feature of the magnetic field in LV model, not necessarily in the inflationary era, where it naturally appears. We refer the reader for a detailed discussion of this problem to Campanelli [15]. In his paper the Ratra model is discussed using the inflaton and LV in such a way that the backreaction problems could be avoided.…”

Section: Riemann-cartan Geometry and Lorentz Symmetry Breakingmentioning

confidence: 99%

Lorentz violation bounds from torsion trace fermion sector and galaxy M 51 data and chiral dynamos

Andrade

2017

Eur. Phys. J. C

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Earlier we have computed a Lorentz violation (LV) bound for torsion terms via galactic dynamos and found bounds similar to the one obtained by Kostelecky et al. (Phys Rev Lett 100:111102, 2008) which is of the order of 10 −31 GeV. Their result was found making use of the axial torsion vector in terms of Dirac spinors and minimal torsion coupling in flat space-time of fermions. In this paper, a torsion dynamo equation obtained using the variation of the torsion trace and galaxy M51 data of 500 pc are used to place an upper bound of 10 −26 GeV in LV, which agrees with the one by Kostelecky and his group using an astrophysical framework background. Their lowest bound was obtained in earth laboratory using dual masers. One of the purposes of this paper is to apply the Faraday self-induction magnetic equation, recently extended to torsioned space-time, by the author to show that it lends support to physics in Riemann-Cartan space-time, in several distinct physical backgrounds. Backreaction magnetic effects are used to obtain the LV bounds. Previously Bamba et al. (JCAP 10:058, 2012) have used the torsion trace in their teleparallel investigation of the IGMF, with the argument that the torsion trace leads to less weaker effects than the other irreducible components of the torsion tensor. LV is computed in terms of a chiral-torsion-like current in the new dynamo equation analogous to the Dvornikov and Semikoz dynamo equation with chiral magnetic currents. Making use of the chiral-torsion dynamo equation we estimate the LV bounds in the early universe to be of the order of 10 −24 GeV, which was the order of the charged-lepton sector. Our main result is that it is possible to obtain more stringent bounds than the ones found in the fermion sector of astrophysics in the new revised 2017 data table for CPT and Lorentz violation by Kostelecky and Mewes. They found in several astrophysical backgrounds, orders of magnitude such as 10 −24 and 10 −23 GeV which are not so stringent as the one found here, of 10 −26 GeV, in the torsion fermionic sector with the help of galaxy M51 data. It is also shown that nona e-mail: garcia@dft.if.uerj.br gauge invariance of chiral dynamos and axial anomalies are obtained from the noninvariance of the electric fields under torsion spatial translations.

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“…One may also consider vector terms in the action that contribute negatively to the energy density, such that the vector's kinetic energy is cancelled out. See [35] for an attempt along this line, and [15] for discussions on negative interaction energy. However it should also be noted that even if the electric fields are cancelled out from the energy density, they can still give rise to Schwinger production of charged particles and prevent the magnetic fields from growing.…”

Section: Discussionmentioning

confidence: 99%

Constraints on primordial magnetic fields from inflation

Green

Kobayashi

2016

J. Cosmol. Astropart. Phys.

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We present generic bounds on magnetic fields produced from cosmic inflation. By investigating field bounds on the vector potential, we constrain both the quantum mechanical production of magnetic fields and their classical growth in a model independent way. For classical growth, we show that only if the reheating temperature is as low as T reh 10 2 MeV can magnetic fields of 10 −15 G be produced on Mpc scales in the present universe. For purely quantum mechanical scenarios, even stronger constraints are derived. Our bounds on classical and quantum mechanical scenarios apply to generic theories of inflationary magnetogenesis with a two-derivative time kinetic term for the vector potential. In both cases, the magnetic field strength is limited by the gravitational back-reaction of the electric fields that are produced simultaneously. As an example of quantum mechanical scenarios, we construct vector field theories whose time diffeomorphisms are spontaneously broken, and explore magnetic field generation in theories with a variable speed of light. Transitions of quantum vector field fluctuations into classical fluctuations are also analyzed in the examples.

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Lorentz-violating inflationary magnetogenesis

Cited by 35 publications

References 145 publications

Enhancing the cross-correlations between magnetic fields and scalar perturbations through parity violation

Enhancing the cross-correlations between magnetic fields and scalar perturbations through parity violation

Lorentz violation bounds from torsion trace fermion sector and galaxy M 51 data and chiral dynamos

Constraints on primordial magnetic fields from inflation

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