Surveying the early Universe in numerical cosmology

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K17695
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Rikkyo University
• Principal Investigator: HIRAMATSU Takashi 立教大学, 理学部, ポストドクトラルフェロー (50456175)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 宇宙論 / 重力波 / 宇宙マイクロ波背景放射 / 修正重力理論 / 宇宙紐 / 数値宇宙論 / インフレーション

Outline of Final Research Achievements

In the extremely early Universe, the Universe experienced the extremely high-energy phenomena such as inflation, the reheating process, and the phase transition of vacuum states. In this research, we focused on the high-precision observations of the cosmic microwave background (CMB) and the future observations of the gravitational wave background with space-borne detectors to survey such high-energy phenomena. In particular, we put emphasis on estimating how well we can extract their information from the observations quantitatively using the field-theoretic simulator and the CMB Boltzmann solver that I have been developing. Moreover, we also focused on the generalised theories of gravity beyond the General Relativity (GR) which affect the generation and propagation of gravitational waves, and estimated to what extent we can see the differences from GR.

Free Research Field

宇宙論

Academic Significance and Societal Importance of the Research Achievements

本研究では、形式的な議論もしくは定式化しかされていないような様々な初期宇宙の理論を、場の理論的シミュレーションや CMB ボルツマンソルバーを使って実際にシミュレーションすることで、様々な宇宙観測に対する理論予言を定量的に行った点に意義が有ります。観測機器の能力の飛躍的な向上が見られる近年、理論側でもこのような本研究のような具体化がより進むよう一石を投じることができたと考えています。