Stability of axion dark matter-photon conversion
Stability of axion dark matter-photon conversion
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轴子暗物质-光子转换的稳定性
DOI：
10.1103/physrevd.101.043505
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发表时间：
2020
影响因子：
5
通讯作者：
Soda Jiro
中科院分区：
文献类型：
--
作者：
Masaki Emi;Aoki Arata;Soda Jiro
众所周知，相干振荡的轴子场是暗物质的候选者之一。在振荡轴子存在的情况下，通过参数放大可以共振地产生光子。宇宙中也存在着宇宙磁场，它们是相干电磁场。在磁场存在的情况下，轴子可以转化为光子，反之亦然。因此，研究轴子-光子系统在轴子暗物质和磁场同时存在的情况下会发生什么是很有趣的。这个系统可以看作是一个轴子和光子的耦合系统，它的方程包含Mathieu型项。我们发现，与传统的Mathieu方程相比，磁场的存在改变了不稳定性条件。稳定和不稳定之间的分岔点位置发生了移位，出现了新的不稳定带。这是因为共振放大的轴子可以转化为光子，反之亦然。
It is known that a coherently oscillating axion field is a candidate of the dark matter. In the presence of the oscillating axion, the photon can be resonantly produced through the parametric amplification. In the universe, there also exist cosmological magnetic fields which are coherent electromagnetic fields. In the presence of magnetic fields, an axion can be converted into a photon, andvice versa. Thus, it is interesting to investigate what happens for the axion-photon system in the presence of both the axion dark matter and the magnetic fields. This system can be regarded as a coupled system of the axion and the photon whose equations contain the Mathieu type terms. We find that the instability condition is changed in the presence of magnetic fields in contrast to the conventional Mathieu equation. The positions of bifurcation points between stable and unstable are shifted and new instability bands appear. This is because the resonantly amplified axion can be converted to photon, andvice versa.