论文标题
蓝倾斜通货膨胀张量光谱并根据纳米级结果加热
Blue-tilted inflationary tensor spectrum and reheating in the light of NANOGrav results
论文作者
论文摘要
我们讨论了用蓝倾斜原始光谱通过通货膨胀引力波（IGW）来解释最近的纳米格拉夫结果的可能性。 Although such IGWs can account for the NANOGrav signal without contradicting the upper bound on the tensor-to-scalar ratio at the cosmic microwave background scale, the predicted spectrum is in strong tension with the upper bound on the amplitude of the stochastic gravitational wave background by big-bang nucleosynthesis (BBN) and the second LIGO-Virgo observation run.然而，宇宙的热历史（例如再加热和末日熵产生）会影响IGW的光谱，并允许逃避上限。我们表明，对于标准再加热方案，当加热温度相对较低时，蓝色张量光谱可以解释最近的Nanograv信号，而不会与BBN和Ligo-Virgo约束相矛盾。我们进一步发现，当人们考虑延迟熵产生时，即使是即时加热的情况，也可以解释纳米格拉夫信号。
We discuss the possibility of explaining the recent NANOGrav results by inflationary gravitational waves (IGWs) with a blue-tilted primordial spectrum. Although such IGWs can account for the NANOGrav signal without contradicting the upper bound on the tensor-to-scalar ratio at the cosmic microwave background scale, the predicted spectrum is in strong tension with the upper bound on the amplitude of the stochastic gravitational wave background by big-bang nucleosynthesis (BBN) and the second LIGO-Virgo observation run. However, the thermal history of the Universe, such as reheating and late-time entropy production, affects the spectral shape of IGWs at high frequencies and permits evading the upper bounds. We show that, for the standard reheating scenario, when the reheating temperature is relatively low, a blue tensor spectrum can explain the recent NANOGrav signal without contradicting the BBN and the LIGO-Virgo constraints. We further find that, when one considers a late-time entropy production, the NANOGrav signal can be explained even for an instant reheating scenario.
