Gravitational waves from axion domain walls in double level crossings
arxiv(2024)
摘要
We investigate the nano-Hertz gravitational waves emitted by axion domain
walls annihilation from the double level crossings. The double level crossings
exists in the mass mixing between two axion fields, one of which is the
Z_𝒩 QCD axion. Here we consider a general mixing case that the
heavy and light mass eigenvalues do not necessarily have to coincide with the
axion masses. In order to form the domain walls, the axions should start to
oscillate slightly before the first level crossing, and the initial oscillation
energy density should be large to climb over the barrier of potential. In this
case, the axion dynamics has a chaotic run-away behavior, which is considered
to be accompanied by domain walls formation. Then we investigate the
gravitational waves emitted by axion domain walls annihilation, which is
determined by their peak frequency and peak amplitude. Finally, we show the
predicted nano-Hertz gravitational waves spectra from the double level
crossings, which can be tested by the current and future pulsar timing array
projects.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要