Real-time Chern-Simons term for hypermagnetic fields

Laine, M.

doi:10.1088/1126-6708/2005/10/056

Cited by 39 publications

(40 citation statements)

References 54 publications

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“…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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Section: Introductionmentioning

confidence: 99%

Evolution of primordial magnetic fields in mean-field approximation

Campanelli

2014

Eur. Phys. J. C

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“…We shall call it the chiral plasma instability. Closely related instability was studied within the electroweak theory at large lepton chemical potential [19,20] and in the context of the early Universe at T ≫ µ 5 [21][22][23] where it is ascribed to a possible origin of the primordial magnetic field.…”

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confidence: 99%

Chiral Plasma Instabilities

2013

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We study the collective modes in relativistic electromagnetic or quark-gluon plasmas with an asymmetry between left-and right-handed chiral fermions, based on the recently formulated kinetic theory with Berry curvature corrections. We find that there exists an unstable mode, signaling the presence of a plasma instability. We argue the fate of this "chiral plasma instability" including the effect of collisions, and briefly discuss its relevance in heavy ion collisions and compact stars.PACS numbers: 12.38. Aw, 11.10.Wx, 12.38.Mh Introduction.-Parity violating effects related to quantum anomalies play an important role in a wide range of physics from quantum Hall systems to cosmology. One example in the transport phenomena is the parity violating current in the presence of a magnetic field and an asymmetry between left and right-handed fermions, parametrized by the chiral chemical potential µ 5 ≡ µ R − µ L . This is called the chiral magnetic effect (CME) [1][2][3][4][5]. Recently hydrodynamics [6] and kinetic theory [7][8][9][10][11] have been appropriately modified to describe quantum anomalies and the CME (see also Refs. [12,13]); in the kinetic theory, essential corrections are the Berry curvature, the concept diversely applied in condensed matter physics [14,15]. These developments enable us to systematically understand the properties and dynamical evolution of various systems with hitherto neglected anomalous effects.

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“…At high temperatures and finite fermion densities, the Chern-Simons terms emerge in the effective Lagrangian densities of SU(2) L and U Y (1) gauge fields due to their chiral couplings to fermions [45][46][47]. The U Y (1) Chern-Simons term leads to the appearance of a new anomalous term in the magnetohydrodynamic equations which are subsequently called the anomalous MHD (AMHD) equations [45,48].…”

Section: Introductionmentioning

confidence: 99%

“…As mentioned earlier, the evolution equations of the anomalous charge densities acquire a hypermagnetic source term as well (the Abelian anomaly). The mutual effects of the fermions and hypermagnetic fields on each other might have major effects in cosmology [45,[47][48][49]. As a matter of fact, some authors believe that the evolutions of matter-antimatter asymmetries and the hypermagnetic field are intertwined [45,47,48,[50][51][52][53][54][55][56][57][58][59].…”

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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Real-time Chern-Simons term for hypermagnetic fields

Cited by 39 publications

References 54 publications

Evolution of primordial magnetic fields in mean-field approximation

Evolution of primordial magnetic fields in mean-field approximation

Chiral Plasma Instabilities

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

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