Magnetic dominance of axion electrodynamics: photon capture effect and anisotropy of Coulomb potential
Magnetic dominance of axion electrodynamics: photon capture effect and anisotropy of Coulomb potential
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DOI：
10.1140/epjc/s10052-021-09046-3
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
S. Villalba-Chávez;A. Shabad;C. Müller
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文献类型：
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作者：
S. Villalba-Chávez;A. Shabad;C. Müller
对于大于与轴子电动力学相关的特征尺度的磁场，由类轴子场引起的量子真空涨落可以主导与电子-正电子场相关的量子真空涨落。通过研究强磁场的轴子修改光子捕获和静态点状电荷的库仑势来探索这个猜想。我们证明，在中子星的磁场特征中，在产生一对光子之前捕获伽马光子可以阻止电子-正电子等离子体的存在，这对于解释脉冲星辐射机制至关重要。这种不兼容性被用来限制轴子参数空间。我们的界限改善了大众领域的现有成果。捕获效应在 QED 中被称为与伽马量子相关，在轴子电动力学中被扩展为包括 X 射线光子，其结果是来自表面的热辐射的特殊极化部分沿着磁场被疏导。此外，我们发现，在发生主导的情况下，运行的QED耦合取决于场强，并且在垂直于磁场的方向上，距离远小于轴子康普顿波长的修正库仑势是汤川型的，而沿着场，它在任何长度尺度上都近似遵循库仑定律。尽管库仑奇点出现在后一种情况中，但我们认为，由于轴子电动力学的不可重整化特征，置于强磁场中的非相对论性氢原子的基态能量是有界的。
For magnetic fields larger than the characteristic scale linked to axion-electrodynamics, quantum vacuum fluctuations due to axion-like fields can dominate over those associated with the electron-positron fields. This conjecture is explored by investigating both the axion-modified photon capture by a strong magnetic field and the Coulomb potential of a static pointlike charge. We show that in magnetic fields characteristic of neutron stars–, the capture of gamma photons prior to the production of a pair can prevent the existence of an electron-positron plasma, essential for explaining the pulsar radiation mechanism. This incompatibility is used to limit the axion parameter space. Our bounds improve existing outcomes in the region of mass–. The effect of capture, known in QED as relating to gamma-quanta, is extended in axion electrodynamics to include X-ray photons with the result that a specially polarized part of the heat radiation from the surface is canalized along the magnetic field. Besides, we find that in the regime in which the dominance takes place, the running QED coupling depends on the field strength and the modified Coulomb potential is of Yukawa-type in the direction perpendicular to the magnetic field at distances much smaller than the axion Compton wavelength, while along the field it follows approximately the Coulomb law at any length scale. Despite the Coulomb singularity manifested in the latter case, we argue that the ground-state energy of a non-relativistic hydrogen atom placed in a strong magnetic field turns out to be bounded due to the nonrenormalizable feature of axion-electrodynamics.