TY - JOUR

T1 - Primordial spectrum of gauge fields from inflation.

AU - Davis, Anne-Christine

AU - Dimopoulos, Konstantinos

AU - Prokopec, Tomislav

AU - Tornkvist, Ola

PY - 2001/3/8

Y1 - 2001/3/8

N2 - We show that conformal invariance of gauge fields is naturally broken in inflation, having as a consequence amplification of gauge fields. The resulting spectrum of the field strength is approximately B_L ~ L^(-1), where L is the relevant coherence scale. One realisation of our scenario is scalar electrodynamics with a scalar whose mass is large enough to evade observational constraints - the obvious candidates being supersymmetric partners of the standard-model fermions. Our mechanism also leads naturally to amplification of the standard-model Z-boson field due to its coupling to the electroweak Higgs field. At preheating, the spectrum of the Z field is transferred to the hypercharge field, which remains frozen in the plasma and is converted into a magnetic field at the electroweak phase transition. With a reasonable model of field evolution one obtains a magnetic field strength of the order of $10^{-29}$ Gauss on a scale of 100 pc, the size of the largest turbulent eddy in a virialised galaxy. Resonant amplification in preheating can lead to primordial fields as large as $10^{-24}$ Gauss, consistent with the seed field required for the galactic dynamo mechanism.

AB - We show that conformal invariance of gauge fields is naturally broken in inflation, having as a consequence amplification of gauge fields. The resulting spectrum of the field strength is approximately B_L ~ L^(-1), where L is the relevant coherence scale. One realisation of our scenario is scalar electrodynamics with a scalar whose mass is large enough to evade observational constraints - the obvious candidates being supersymmetric partners of the standard-model fermions. Our mechanism also leads naturally to amplification of the standard-model Z-boson field due to its coupling to the electroweak Higgs field. At preheating, the spectrum of the Z field is transferred to the hypercharge field, which remains frozen in the plasma and is converted into a magnetic field at the electroweak phase transition. With a reasonable model of field evolution one obtains a magnetic field strength of the order of $10^{-29}$ Gauss on a scale of 100 pc, the size of the largest turbulent eddy in a virialised galaxy. Resonant amplification in preheating can lead to primordial fields as large as $10^{-24}$ Gauss, consistent with the seed field required for the galactic dynamo mechanism.

U2 - 10.1016/S0370-2693(01)00138-1

DO - 10.1016/S0370-2693(01)00138-1

M3 - Journal article

VL - 501

SP - 165

EP - 172

JO - Physics Letters B

JF - Physics Letters B

SN - 0370-2693

IS - 3-4

ER -