Big bang nucleosynthesis constraints on primordial magnetic fields.
Big bang nucleosynthesis constraints on primordial magnetic fields.
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大爆炸核合成对原始磁场的限制。
DOI：
10.1103/physrevd.54.7207
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Tammay Vachaspati
中科院分区：
文献类型：
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作者：
P. Kernan;G. Starkman;Tammay Vachaspati
我们重新分析了磁场在BBN中的作用，结合了以前分析中忽略的几个特征。我们发现，相干磁场对BBN中弱相互作用速率和电子热力学函数（ρe、Pe和dρe/dT）的影响与磁场能量密度的贡献相比并不重要.因此，通过将额外的能量密度作为有效中微子数来处理，可以很好地近似BBN中包含磁场的效果。原始磁场的一个保守上限为ρ B ≤ 2（ρB < 0.27ρ），参数为ρ B = 2 eBrms/（T2 ′）.如果宇宙学磁场是由因果机制产生的，那么这种束缚可能比来自遥远类星体的法拉第旋转测量的传统束缚更强。
We reanalyze the effect of magnetic fields in BBN, incorporating several features which were omitted in previous analyses. We find that the effects of coherent magnetic fields on the weak interaction rates and the electron thermodynamic functions (ρe, Pe, and dρe/dT) are unimportant in comparison to the contribution of the magnetic field energy density in BBN. In consequence the effect of including magnetic fields in BBN is well approximated numerically by treating the additional energy density as effective neutrino number. A conservative upper bound on the primordial magnetic field, parameterized as ζ = 2eBrms/(T 2 � ), is ζ ≤ 2 (ρB < 0.27ρ�). This bound can be stronger than the conventional bound coming from the Faraday rotation measures of distant quasars if the cosmological magnetic field is generated by a causal mechanism.