标题： 宇宙学磁场来自超轻暗物质 显示英文标题

标题： Cosmological Magnetic Fields from Ultralight Dark Matter

摘要： 我们提出了一种在再结合之后起作用的宇宙尺度磁场生成机制。 一个关键因素是电磁场的不稳定性（参数共振类型），该不稳定性由一个振荡的赝标量暗物质场，$\phi$，驱动，该场通过轴子-电动力学拉格朗日量中的一个$\phi F \wedge F$项与电磁场张量耦合。 我们发现，在再结合后不久就可以在$1 {\rm{Mpc}}$尺度上产生超过观测下限的磁场。 显示英文摘要

摘要： We propose a mechanism for the generation of magnetic fields on cosmological scales that is operative after recombination. An essential ingredient is an instability (of parametric resonance type) of the electromagnetic field driven by an oscillating pseudo-scalar dark matter field, $\phi$, that is coupled to the electromagnetic field tensor via a $\phi F \wedge F$ term in the Lagrangian of axion-electrodynamics. We find that magnetic fields larger than the observational lower bounds can be generated soon after recombination on scales of $1 {\rm{Mpc}}$.