Time：14:00-15:30, Aug 26th (Tuesday, Beijing Time), 2025

时间：2025年8月26日（星期二）下午14:00-15:30

Host: Prof. Hongguang Liu, PI of Institute for Theoretical Sciences, Westlake University

主持人: 西湖大学理论科学研究院PI 刘洪光

Venue: E4-233, Yungu Campus, Westlake University

地点: 云谷校区E4-233教室

Lecture Language: English

讲座语言: 英文

何敏熙 博士

韩国基础科学研究院博士后研究员

Dr. Minxi He

Senior Researcher

Institute for Basic Science (IBS), South Korea

主讲人/Speaker:

何敏熙，韩国基础科学研究院博士后研究员。2015年中国科学技术大学毕业，2021年在东京大学取得博士学位，2021至2023年在日本高能加速器研究机构（KEK）做博士后研究，2023年至今在韩国基础科学研究院做博士后研究。主要研究方向为宇宙学与高能物理，目前研究主要集中在早期宇宙暴胀与再加热、原初黑洞、修改引力、天体物理方法探测超出标准模型粒子。

Minxi He is a senior researcher at Institute for Basic Science (IBS) in South Korea. He graduated from University of Science and Technology of China in 2015 and received his PhD in 2021 at The University of Tokyo. After that, he worked at a postdoc at KEK in Japan from 2021 to 2023 and moved to IBS from 2023. His main research interest is cosmology and high-energy physics. So far, he has been working on cosmic inflation and reheating of the early Universe, primordial black hole, modified gravity, and astrophysical probe of new particles beyond the Standard Model.

摘要/Abstract:

The Higgs inflation is the minimal inflation model within general relativity and the Standard Model of particle physics, and gives predictions on cosmic microwave background favored by the Planck experiment. However, the validity of this model as an effective field theory (EFT) is jeopardized by its low UV cutoff, because unitarity is violated during preheating. Due to the multi-field nature of this model, the UV cutoff is determined by the geometry of the target space as in the non-linear sigma model, which is independent of field redefinition. However, this uniqueness is obscured by the freedom of redefinition of the spacetime metric in the presence of gravity. To unambiguously calculate the cutoff scale which is essential for the EFT discussion, we propose an extended target space whose geometry is independent of the conformal transformation of the spacetime metric. I will discuss the application of this new method to the Higgs inflation in the metric and the Einstein-Cartan formalism. I may also briefly discuss the preheating process.

讲座联系人/Contact:

Wenxin Zhang, the Institute for Theoretical Sciences

Email: zhangwenxin@westlake.edu.cn