论文标题
中间频率和宇宙扩展历史的遗物引力
Relic gravitons at intermediate frequencies and the expansion history of the Universe
论文作者
论文摘要
宇宙的早期扩展历史通过结合了音频带中宇宙重力的最新限制以及NHz域的所谓证据。最简单的场景规定，在通货膨胀结束和光核的形成之间，进化是由一个单相扩展的速度，其速度比辐射的速度更快或更慢。如果相反，有多个通货膨胀后阶段以不同的速率演变，则光谱能量密度始终散发出可能归因于中间频率的Pulsar Pime阵列可能归因于遗物重力的信号，但最终会发展出局部最大值。在检查了进一步的互补可能性（例如，在低尺度上存在通货膨胀的次级阶段），我们分析了有效扩展率的早期修饰，并认为，如果Relic Readons的屈光度指数在传统通货膨胀时期内增加，则在传统的通货膨胀时期内，光谱能量密度在FHz上方蓝色，然后在FLATTENCE上浮出水面。在这种情况下，信号与未确认的NHz观测值兼容，与宽带干涉仪的最新限制以及通常在通货膨胀过程中产生的遗物重力的背景的进一步约束。
The early expansion history of the Universe is constrained by combining the most recent limits on the cosmic gravitons in the audio band and the claimed evidences of the nHz domain. The simplest scenario stipulates that between the end of inflation and the formation of light nuclei the evolution consists of a single phase expanding at a rate that is either faster or slower than the one of radiation. If there are instead multiple post-inflationary stages evolving at different rates, the spectral energy density always undershoots the signals potentially attributed to relic gravitons by the pulsar timing arrays at intermediate frequencies but ultimately develops a local maximum. After examining further complementary possibilities (like the presence of a secondary stage of inflation at low-scales) we analyze the early modifications of the effective expansion rate and argue that if the refractive index of the relic gravitons increases during a conventional inflationary epoch the spectral energy density is blue above the fHz and then flattens out in the $μ$Hz region. In this instance the signal is compatible with the unconfirmed nHz observations, with the most recent limits of the wide-band interferometers and with the further constraints customarily imposed on the backgrounds of relic gravitons produced during inflation.
