【02.05】Seminar：Cosmic Evolution and Direct Detection of QCD Axion
Seminar
报告题目：Cosmic Evolution and Direct Detection of QCD Axion
报告人：吕坤峰, 博士后，University of Oklahoma
主持人：任婧，研究员，中国科学院高能物理研究所
报告时间：2026年2月5日（周四），下午14:00
ZOOM：98561154024 / 123456
链接：https://zoom.us/j/98561154024?pwd=tEir5Na8qvagcjhUWrfYaQzas8beu3.1
报告摘要：
The QCD axion is a compelling dark matter candidate, whose cosmological evolution can be highly sensitive to non-standard thermal histories in the early Universe. Firstly, the NANOGrav GW signal implies our universe may undergo a suprooled phase transition near the QCD scale. We show this may lead to a modification of the axion dark matter abundance and the formation of axion domain walls without cosmic strings in the minimal QCD axion scenario. We further construct models realizing a lighter QCD axion that solves the strong CP problem, and study the detailed cosmic evolution dubbed as hilltop misalignment. Finally, we propose a new experimental strategy to probe light QCD axion dark matter using Mössbauer spectroscopy. The coherent axion field induces time-dependent shifts of nuclear binding energy that can be detected via the 109Ag transition. This approach significantly extend search capability and probe a vast, unexplored region of axion parameter space.
个人简介：
Kunfeng Lyu (吕坤峰) is currently a postdoc at University of Oklahoma in US. Before that, he obtained his PhD at Hong Kong University of Science and Technology in 2021 and then served as the postodotoral researcher in University of Minnesota from 2021 to 2024 and University of Utah from 2024 to 2025. His research focuses on particle physics beyond the Standard Model and scattering amplitude, and more recently the axion physics espeically topological defect and direct detection.
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