Production and detection of relic gravitons in quintessential inflationary models
Production and detection of relic gravitons in quintessential inflationary models
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DOI：
10.1103/physrevd.60.123511
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发表时间：
1999-02
影响因子：
5
通讯作者：
M. Giovannini
中科院分区：
文献类型：
--
作者：
M. Giovannini
最近由皮布尔斯和Vilenkin提出的一大类典型的暴胀模型导致了后暴胀阶段，其有效状态方程比辐射更硬。预期的引力波对数能谱倾向于高频率，其特征在于两个参数：暴胀曲率尺度，在该尺度下发生向刚性相的过渡，以及（非共形耦合）标量自由度的数量，其衰变为费米子触发宇宙引力再加热的开始。根据模型的参数和不同的暴胀动力学（在刚性演化开始之前），对于大于1 Hz的频率，残余引力子的能量密度可以比标准暴胀模型中的大得多。我们估计所需的灵敏度检测预测的光谱振幅，并表明，我们的参数空间的允许区域导致信号小于（由一个1.5数量级）比先进的LIGO灵敏度在0.1千赫的频率。在我们的背景下，最大的信号预计在GHz区域，在那里残余引力子的能量密度在临界单位（即h_0^2\Omega_{GW}$）的数量级为10 ^{-6}$，大约比普通的暴胀模型大8个数量级。较小的探测器（不一定是干涉仪）可能与GHz频率窗口中的探测目的有关。我们建议/推测，未来的测量通过微波腔可以提供有趣的观点。
A large class of quintessential inflationary models, recently proposed by Peebles and Vilenkin, leads to post-inflationary phases whose effective equation of state is stiffer than radiation. The expected gravitational waves logarithmic energy spectra are tilted towards high frequencies and characterized by two parameters: the inflationary curvature scale at which the transition to the stiff phase occurs and the number of (non conformally coupled) scalar degrees of freedom whose decay into fermions triggers the onset of a gravitational reheating of the Universe. Depending upon the parameters of the model and upon the different inflationary dynamics (prior to the onset of the stiff evolution) the relic gravitons energy density can be much more sizeable than in standard inflationary models, for frequencies larger than 1 Hz. We estimate the required sensitivity for detection of the predicted spectral amplitude and show that the allowed region of our parameter space leads to a signal smaller (by one 1.5 orders of magnitude) than the advanced LIGO sensitivity at a frequency of 0.1 KHz. The maximal signal, in our context, is expected in the GHz region where the energy density of relic gravitons in critical units (i.e. $h_0^2 \Omega_{GW}$) is of the order of $10^{-6}$, roughly eight orders of magnitude larger than in ordinary inflationary models. Smaller detectors (not necessarily interferometers) can be relevant for detection purposes in the GHz frequency window. We suggest/speculate that future measurements through microwave cavities can offer interesting perspectives.