表題番号:2021C-569 日付:2022/04/08
研究課題Dark Energy Model Satisfying the Solar System Observations
研究者所属(当時) 資格 氏名
(代表者) 理工学術院 先進理工学部 講師 パンパーニッチ シラチャック
(連携研究者) Waseda University Professor Kei-ichi MAEDA
研究成果概要
We study the modified gravity theory, names cuscuta-galileon gravity to explain the accelerated expansion of the universe by using a nondynamical scalar field. We find that the model can provide the sequence of the thermal history of the universe correctly, in the same time the gravitational coupling is modified from the Newtonian gravitational constant. Interestingly, the new gravitational coupling depends on time, then it leads to a changing on the Hubble parameter. As a result, the present value of the Hubble parameter in our model increases from the standard model of cosmology, the Lambda-Cold-Dark-Matter model, about 10%, then it might be a tendency to solve one of the recent problems in cosmology, so-called the Hubble tension problem. Observations in universe such as Big-Bang-Nucleosysthesis and Lunar-Laser-Ranging also provide constraints on parameters of the model, however the model can satisfy these observations. The above results have been done under some conditions, namely we assume an exponential form of potential for the scalar field. Thus other forms of potential may give other possibilities and results. We also improve the model by adding a small negative vacuum energy, it leads to a smaller of the present value of the Hubble parameter which satisfies the latest observations on Super Novae Type IA.