论文标题
可以在通货膨胀的场景中形成轴支吗？
Can axion clumps be formed in a pre-inflationary scenario?
论文作者
论文摘要
QCD轴和轴突状粒子（ALP）是暗物质的引人注目的候选者。对于QCD轴，众所周知，当Peccei-Quinn（PQ）对称性在通货膨胀后会自发损坏时，较大的初始波动会导致轴突团块的形成。另一方面，当对称性在通货膨胀期间已经断裂时，人们相信由于初始轴是自发的幅度较小，因此不会发生轴突团块的形成。考虑到QCD轴和ALP，我们重新审视了这种普遍的理解。我们发现，对于QCD轴，即使我们考虑了极度微调的初始条件，也不会发生团块的形成。同时，事实证明，对于允许更一般的电势形式的ALP，考虑到多余的余弦电位，可以通过速度不稳定性或/和共振不稳定性进行团块形成。
The QCD axion and an axion-like particle (ALP) are compelling candidates of dark matter. For the QCD axion, it is known that when the Peccei-Quinn (PQ) symmetry is spontaneously broken after inflation, the large initial fluctuation can lead to axion clump formation. On the other hand, when the symmetry is already broken during inflation, it has been believed that the axion clump formation does not occur due to the small amplitude of the initial axion fluctuation. We revisit this prevailing understanding, considering both the QCD axion and an ALP. We find that for the QCD axion, the clump formation does not occur even if we consider an extremely fine-tuned initial condition. Meanwhile, it turns out that for an ALP which allows a more general potential form, the clump formation can take place through the tachyonic instability or/and the resonance instability, considering a multiple cosine potential.
