论文标题
来自相变的重力波中的大原始波动
Large Primordial Fluctuations in Gravitational Waves from Phase Transitions
论文作者
论文摘要
众所周知，早期宇宙中的一阶相变可能是可观察到的随机重力波背景的强大来源。任何这样的引力波背景必须表现出至少与CMB $ \ sim 10^{ - 5} $中的大规模各向异性，从而为原始波动的（通货膨胀）起源提供了一个有价值的新窗口。虽然可以明显的分数各向异性（例如，在多场通货膨胀中），并且更容易解释，但有人认为，如果重力波信号相应地较小，则只有与CMB边界保持一致。在本文中，我们表明，如果存在某种强大类型的早期物质优势时代，则可以避免这种依赖于早期宇宙的辐射优势的论点。这允许大型引力波各向异性与所提出的未来重力波检测器上可观察的信号一致。在小尺度上从CMB以及小尺度上的原始黑洞和迷你群集形成以及次级标量引起的重力波的约束都考虑在内。
It is well-known that first order phase transitions in the early universe can be a powerful source of observable stochastic gravitational wave backgrounds. Any such gravitational wave background must exhibit large-scale anisotropies at least as large as those seen in the CMB $\sim 10^{-5}$, providing a valuable new window onto the (inflationary) origins of primordial fluctuations. While significantly larger fractional anisotropies are possible (for example, in multi-field inflation) and would be easier to interpret, it has been argued that these can only be consistent with CMB bounds if the gravitational wave signal is correspondingly smaller. In this paper, we show that this argument, which relies on assuming radiation dominance of the very early universe, can be evaded if there is an era of early matter dominance of a certain robust type. This allows large gravitational wave anisotropies to be consistent with observable signals at proposed future gravitational wave detectors. Constraints from the CMB on large scales, as well as primordial black hole and mini-cluster formation on small scales, and secondary scalar-induced gravitational waves are all taken into account.
