AI 中文总结
该研究分析了轴子畴壁的演化，发现畴壁坍缩产生的轴子可使等曲率扰动在畴壁湮灭后仍存活，并探讨了相关暗物质的等曲率约束。
AI 中文摘要
我们重新研究了由暴胀涨落产生的轴子畴壁的演化。在我们之前的工作中，我们表明这类畴壁网络即使进入标度 regime 后仍保留超视界关联。我们将之前的分析扩展到初始涨落较大的情况，此时轴子开始振荡时，轴子势的多个极小值已被占据。尽管在对多个真空取平均时，传统的错排贡献可能会抑制长波等曲率扰动，但畴壁坍缩产生的轴子提供了额外贡献，当畴壁在湮灭前进入标度 regime 时，该贡献可占主导地位。特别地，畴壁湮灭过程中释放的偏置真空能量继承了暴胀涨落的超视界关联，并将其传递给轴子能量密度。我们发现，即使在畴壁湮灭后，相当大的等曲率扰动仍可存活。我们还讨论了畴壁坍缩产生的暗物质的一般等曲率约束。
英文摘要
We revisit the evolution of axion domain walls seeded by inflationary fluctuations. In our previous work, we showed that such domain-wall networks retain superhorizon correlations even after entering the scaling regime. We extend our previous analysis to the case with large initial fluctuations, where many minima of the axion potential are already populated when the axion starts to oscillate. Although the conventional misalignment contribution can have suppressed long-wavelength isocurvature perturbations when many vacua are averaged over, axions produced by domain-wall collapse provide an additional contribution that can dominate when the walls enter the scaling regime before annihilation. In particular, the biased vacuum energy released during wall annihilation inherits the superhorizon correlations of the inflationary fluctuations and transfers them to the axion energy density. We find that sizable isocurvature perturbations can therefore survive even after the walls annihilate. We also discuss generic isocurvature constraints on dark matter produced by domain-wall collapse.
Comments34 pages, 10 figures, comments welcome!
