Probing the early universe by stochastic gravitational wave background

用随机引力波背景探测早期宇宙

• 批准号: 20K14461
• 负责人: 皮 石
• 金额: $ 2.66万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Early-Career Scientists
• 财政年份: 2020
• 资助国家: 日本
• 起止时间: 2020-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-20K14461/
• 关键词: gravitational waves; primordial black holes; curvature perturbation; inflation; δN formalism; pulsa timing array; curvaton scenario; swampland conjecture; cosmology

In September 2022 I finished a paper with my student: "Primordial Black Hole Formation in Starobinsky's Linear Potential Model", Shi Pi and Jianing Wang, e-Print: 2209.14183, accepted by JCAP. We revisit Starobinsky model with a piecewise linear potential, and find the exact position and height of the maximum of the power spectrum of the curvature perturbation, which is useful for determining the primordial black hole (PBH) formation.In November 2022 I finished a paper with Prof. Misao Sasaki: "Logarithmic Duality of the Curvature Perturbation", Shi Pi and Misao Sasaki, e-Print: 2211.13932. We studied single-field inflation with a piecewise quadratic potential. By using (classical) δΝ formalism, we found that in general the curvature perturbation can be expressed by a sum of logarithmic functions of the inflaton field perturbation δφ, while each logarithmic expression has a dual expression due to the second-order nature of the equation of motion. We clarified the condition under which a single logarithm dominates, which yields either the renowned "exponential tail" of the PDF of R or a Gumbel-distribution-like tail. Our formula unifies all previous works on the fully nonlinear PDFs of the curvature perturbation, including USR inflation, slow-roll inflation, constant-roll inflation, curvaton scenario, etc., and reveals new analytically solvable models. It sheds light on accurate calculation of the PBH formation and the induced gravitational wave spectrum.

2022年9月，我与我的学生一起完成了一篇论文：“ Starobinsky的线性潜在模型中的原始黑洞组”，Shi Pi和Jianing Wang，E-Print：2209.14183，由JCAP接受。我们以分段线性潜力重新访问Starobinsky模型，并找到曲率扰动功率谱的最大功率谱的确切位置和高度，这对于确定2022年11月的原始黑洞（PBH）形成很有用。电子打印：2211.13932。我们研究了单场通货膨胀，具有分段二次电位。通过使用（经典）Δν形式，我们发现通常，曲率扰动可以通过充气场扰动Δφ的对数函数的总和来表达，而每个对数表达式由于运动方程的二阶性质而具有双重表达。我们阐明了单个对数主导的条件，该条件产生了R的PDF的著名“指数尾巴”或类似gumbel-Distribution的尾巴。我们的公式统一了曲率扰动的完全非线性PDF的所有以前的作品，包括USR通货膨胀，缓慢倾斜的通货膨胀，恒定通货膨胀，curvaton方案等，并揭示了新的分析可解决模型。它阐明了PBH形成和诱导的重力波谱的准确计算。

项目成果

Primordial black holes and gravitational waves from resonant amplification during inflation

• DOI: 10.1103/physrevd.102.103527
• 发表时间: 2020-10
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Zihan Zhou;Jie Jiang;Yi-Fu Cai;M. Sasaki;Shi Pi

Measuring the Gravitomagnetic Distortion from Rotating Halos. I. Methods

• DOI: 10.3847/1538-4357/abe69e
• 发表时间: 2020-09
• 期刊: The Astrophysical Journal
• 作者: Chengfeng Tang;Pierre Zhang;Wentao Luo;Nan Li;Yi-Fu Cai;Shi Pi

Universal upper bound on the inflationary energy scale from the trans-Planckian censorship conjecture

• DOI: 10.1103/physrevd.102.021301
• 发表时间: 2020-07-21
• 期刊: PHYSICAL REVIEW D
• 影响因子: 5
• 作者: Mizuno, Shuntaro;Mukohyama, Shinji;Zhang, Yun-Long
• 通讯作者: Zhang, Yun-Long

NANOGrav hints on planet-mass primordial black holes

• DOI: 10.1007/s11433-021-1839-6
• 发表时间: 2020-10
• 期刊: Science China Physics, Mechanics & Astronomy
• 作者: Guillem Domènech;Shi Pi

NANOGrav 12.5-yr result and induced gravitational waves

NANOGrav 12.5 年结果和感应引力波

• 发表时间: 2021
• 作者: Liugang Hu;Takayoshi Tsutsumi;Thi-Thuy-Nga Nguyen;Shih-Nan Hsiao;Hiroki Kondo;Kenji Ishikawa;Makoto Sekine;and Masaru Hori;Seyed Morteza Hosseini;Shi Pi;小笠原康太，伊形尚久;加藤ちなみ，平井遼介，長倉洋樹;Green Bank and Effelsberg Radio Telescope Searches for Axion Dark Matter Conversion in Neutron Star Magnetospheres;B. Arora and Pankaj Attri*;Aoki Katsuki;Shi Pi
• 通讯作者: Shi Pi