Phase Transition of High Density Matter in the Universe

本研究的结果归纳为以下三组。1)早期宇宙：一种新的量子宇宙学方法，其中时间是明确出现的概率总是正定的，制定（细谷）。系统地研究了暴胀宇宙中的重子生成。结果表明：（1）再加热阶段的非热效应起着重要作用;（2）在混沌暴胀情况下，可能形成重子数畴结构（Sato）。研究了早期宇宙中相变形成的密度波动的演化，并明确了3 k背景辐射的均匀性对模型的约束（Sasaki）。研究了轻子数不对称宇宙中的核合成，发现对轻子数不对称宇宙中的核合成有更严格的限制。2）超新星和中子星星：对超新星1987 A的中微子爆发进行了理论分析，发现：（1）中微子爆发与理论预言惊人地一致;（2）中子星星的质量可能为1.2- 1.6 M，iii）电子型中微子的质量必须小于26 eV（Sato）。对有限温度夸克胶子等离子体进行了MonteCalro模拟，发现其跃迁为一级跃迁（UKawa）。3）高密度等离子体：研究了太阳中心的两相分离（氢离子和铁离子），发现不存在这种分离（Ichimaru）。根据Weinberg-Salam理论（Itoh）详细计算了中微子损失率。

Results of the present research are summarized in the following three group. 1) Early Universe: A new method for quantum cosmology, in which the time is explicitly appeared and the probability is always positive definite, was formulated (Hosoya). Baryogenesis in the inflationary universe was investigated systematically. It was found that i) non thermal effects in the reheating stage play an important role, ii) in the chaotic inflationary scenario, baryon number domain structure might be formed (Sato). Evolution of density fluctuations which are formed by the phase transition in the early universe was investigated and the constraints on the model imposed from the homogeneity of 3k background radiation was made clear (Sasaki). Nucleosynthesis in the lepton-number asymmetric universe was investigated and it was found that more stringent constraints on the asymmetry is obtained.2) Supernova and Neutron Star: Theoretical analysis of neutrino burst from the Supernova 1987A was made and it was found that i) the burst is surprisingly consistent with theoretical prediction, ii) The mass of neutron star just born might be 1.2-1.6M, iii) The mass of electron type neutrinos mast be smaller than 26 eV (Sato). Monte Calro simulation of finite temperature quark gluon plasma was made and it was found that the transition is of first order (UKawa).3) High density plasma: Two phase separation (hydrogen and iron ions) in the center of the sun was investigated and it was found this separation does not occur (Ichimaru). Neutrino loss rate was calculated in detail on the basis of Weinberg-Salam theory (Itoh).