Can slow roll inflation induce relevant helical magnetic fields?

Durrer, Ruth; Hollenstein, Lukas; Jain, Rajeev Kumar

doi:10.1088/1475-7516/2011/03/037

Cited by 147 publications

(184 citation statements)

References 83 publications

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“…[21][22][23][24][25][26][27][42][43][44][45][46][47][48][49][50][51][52], in order to explain the origin of the large-scale magnetic fields in our universe. In such inflationary magnetogenesis scenarios, the magnetic fields are generically accompanied by the production of even larger electric fields.…”

Section: Constraints On Inflationary Magnetogenesismentioning

confidence: 99%

Schwinger effect in 4D de Sitter space and constraints on magnetogenesis in the early universe

Kobayashi

Afshordi

2014

J. High Energ. Phys.

145

229

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We investigate pair creation by an electric field in four-dimensional de Sitter space. The expectation value of the induced current is computed, using the method of adiabatic regularization. Under strong electric fields the behavior of the current is similar to that in flat space, while under weak electric fields the current becomes inversely proportional to the mass squared of the charged field. Thus we find that the de Sitter space obtains a large conductivity under weak electric fields in the presence of a charged field with a tiny mass. We then apply the results to constrain electromagnetic fields in the early universe. In particular, we study cosmological scenarios for generating large-scale magnetic fields during the inflationary era. Electric fields generated along with the magnetic fields can induce sufficiently large conductivity to terminate the phase of magnetogenesis. For inflationary magnetogenesis models with a modified Maxwell kinetic term, the generated magnetic fields cannot exceed 10 −30 G on Mpc scales in the present epoch, when a charged field carrying an elementary charge with mass of order the Hubble scale or smaller exists in the Lagrangian. Similar constraints from the Schwinger effect apply for other magnetogenesis mechanisms.

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Section: Constraints On Inflationary Magnetogenesismentioning

confidence: 99%

Schwinger effect in 4D de Sitter space and constraints on magnetogenesis in the early universe

Kobayashi

Afshordi

2014

J. High Energ. Phys.

145

229

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“…In particular, inflation-produced magnetic fields usually exhibit a power-law spectrum when they re-enter the horizon. Also, most of the generating mechanisms after inflation [98][99][100][101][102][103][104][105][106][107][108][109][110][111][112] repose on microphysical processes acting only on small scales. Therefore, the structure of the resulting magnetic field appears as a set of uncorrelated (Gaussiandistributed) eddies, which implies a k 2 -like spectrum.…”

Section: Initial Conditionsmentioning

confidence: 99%

“…1 Moreover, models for generating helical magnetic fields in the early universe exist in the literature ( [97]. For generation mechanisms of primordial helical magnetic fields see, e.g., [98][99][100][101][102][103][104][105][106][107][108][109][110][111][112]). …”

Section: Introductionmentioning

confidence: 99%

Evolution of primordial magnetic fields in mean-field approximation

Campanelli

2014

Eur. Phys. J. C

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We study the evolution of phase-transitiongenerated cosmic magnetic fields coupled to the primeval cosmic plasma in the turbulent and viscous free-streaming regimes. The evolution laws for the magnetic energy density and the correlation length, both in the helical and the non-helical cases, are found by solving the autoinduction and Navier-Stokes equations in the mean-field approximation. Analytical results are derived in Minkowski spacetime and then extended to the case of a Friedmann universe with zero spatial curvature, both in the radiation-and the matterdominated era. The three possible viscous free-streaming phases are characterized by a drag term in the Navier-Stokes equation which depends on the free-streaming properties of neutrinos, photons, or hydrogen atoms, respectively. In the case of non-helical magnetic fields, the magnetic intensity B and the magnetic correlation length ξ B evolve asymptotically with the temperature, T , asHere, T i , N i , and v i are, respectively, the temperature, the number of magnetic domains per horizon length, and the bulk velocity at the onset of the particular regime. The coefficients κ B , κ ξ , 1 , 2 , 3 , and 4 , depend on the index of the assumed initial power-law magnetic spectrum, p, and on the particular regime, with the order-one constants κ B and κ ξ depending also on the cutoff adopted for the initial magnetic spectrum. In the helical case, the quasi-conservation of the magnetic helicity implies, apart from logarithmic corrections and a factor proportional to the initial fractional helicity, power-like evolution laws equal to those in the non-helical case, but with p equal to zero.

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“…Therefore, most of the scenarios presented for the generation of the seed fields in the early Universe operate either at a phase transition [28][29][30][31][32][33][34] or during the inflation [35][36][37][38][39][40][41]. The inflationary mechanisms have received a lot of attention, since they have the advantage of achieving super-horizon correlations and therefore generate much more coherent magnetic fields in the early Universe.…”

Section: Introductionmentioning

confidence: 99%

Effects of theUY(1)Chern-Simons term and its baryonic contribution on matter asymmetries and hypermagnetic fields

Zadeh

Gousheh

2017

Phys. Rev. D

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In this paper, we study the significance of the U Y (1) Chern-Simons term in general, and its baryonic contribution in particular, for the evolution of the matter asymmetries and the hypermagnetic field in the temperature range 100GeV≤ T ≤ 10TeV. We show that an initial helical hypermagnetic field, denoted by B (0) Y , can grow matter asymmetries from zero initial value. However, the growth which is initially quadratic with respect to B (0) Y , saturates for values larger than a critical value. The inclusion of the baryonic contribution reduces this critical value, leading to smaller final matter asymmetries. Meanwhile, B Y (T EW ) becomes slightly larger than B (0)Y . In the absence of the U Y (1) Chern-Simons term, the final values of matter asymmetries grow without saturation. Conversely, we show that an initial matter asymmetry can grow an initial seed of hypermagnetic field, provided the Chern-Simons term is taken into account. The growth process saturates when the matter asymmetry drops abruptly. When the baryonic contribution is included, the saturation occurs at an earlier time, and B Y (T EW ) becomes larger. We also show that the baryonic asymmetry and the magnetic field strength can be within the acceptable range of present day data, provided the inverse cascade process is also taken into account; however, the magnetic field scale obtained from this simple model is much lower than the ones usually assumed for gamma ray propagation. * S − Rostamzadeh@sbu.ac.ir † ss−gousheh@sbu.ac.ir 1 arXiv:1607.00650v3 [hep-ph]

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Can slow roll inflation induce relevant helical magnetic fields?

Cited by 147 publications

References 83 publications

Schwinger effect in 4D de Sitter space and constraints on magnetogenesis in the early universe

Schwinger effect in 4D de Sitter space and constraints on magnetogenesis in the early universe

Evolution of primordial magnetic fields in mean-field approximation

Effects of theUY(1)Chern-Simons term and its baryonic contribution on matter asymmetries and hypermagnetic fields

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