报告讲座
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格物致理76期：活动星系核中准周期爆发的观测介绍与模型研究
准周期爆发（QPEs）是一种新型的活动星系核（AGNs）X射线爆发现象，首次由Giovanni Miniutti于2019年在《Nature》上报道提出。QPEs最显著的特征是呈现出稳定的爆发低态和短至小时量级的爆发间隔，这与一般的AGNs光变模式截然不同，且传统的光变理论难以解释如此短时标的爆发现象。本次报告将简要回顾已有的QPEs观测结果，并介绍目前的主要模型及其面临的挑战，最后，报告将分享我们团队在QPEs模型方面的最新进展。
发布者： 发布时间：2025-01-16 11:32:28 -
格物致理75期：Cosmological principle, dark energy and interstellar molecules
The precise validity of cosmological principle and general relativity is the cornerstone of the standard model of modern cosmology (ΛCDM) and is the logical presupposition for the existence of dark energy. Cosmologists usually assumed that the general relativity is the perfect law of gravity from small to large scales, which has been tested by many tests in Solar system and a few cosmological tests. The cosmological principle assumes that the universe is homogeneous and isotropic on a sufficiently large scale. However, several possible challenges to cosmological principle was reported in recent years. In this talk, we will introduce our progresses on the tests of cosmological principle and related works on the models and properties of dark energy, which is the main explanation for cosmic acceleration. At the same time, we will present our recent works on the observations of interstellar molecules, which is the prelude of origin of possible extraterrestrial life.
发布者： 发布时间：2024-12-10 16:33:13 -
天体物理中心系列学术活动：《大规模巡天时代下密近双星的观测研究》
天体物理中心系列学术活动：《大规模巡天时代下密近双星的观测研究》
发布者： 发布时间：2024-12-05 13:19:10 -
2024年天体物理中心系列学术活动之一：大规模巡天时代下密近双星的观测研究
密近双星是一类强相互作用双星系统，密近双星系统内出现的两子星间的物质和能量转移、系统质量和角动量的损失、子星磁活动以及吸积过程等各种复杂相互作用为我们研究这些物理过程提供了良好的机会。本报告将基于TESS巡天望远镜发布的光变曲线数据和LAMOST发布的光谱数据，结合利用国内各大观测站的中小口径光学望远镜对一批密近双星系统进行观测研究，获得它们的基本物理参量的同时探讨其演化状态和结构特征，为理解密近双星的形成、结构和演化过程提供观测证据。
发布者： 发布时间：2024-12-04 10:18:26 -
格物致理73期：BESIII实验上的超子物理研究进展
利用BESIII实验收集的J/psi和psi(3686)大量实验数据，为探究量子关联的正反超子对的产生和衰变提供了新的思路。在BESIII最近的一系列研究中，观察到J/psi和psi(3686)衰变到超子对时呈现出横向极化现象。由于存在非零极化，超子和反超子衰变参数得以首次相互独立确定。通过比较超子和反超子的衰变参数，可以精确验证超子衰变过程的CP对称性。
发布者： 发布时间：2024-11-01 09:22:48 -
格物致理72期：An Introduction to Solitonic Perturbation Methods
In this talk we will talk about more mathematical and fundational aspects of quantization in general, focusing on its difficulties instead of great achievements. Especially, we will talk about the second kind of divergence in quantum field theory, as a motivation to organically integrate the soitonic contribution into QFT as a whole, and the quantization at the presence of a kink. Recall that renormalization is crucial in obtaining finite order-by-order contributions in formal perturbation theory. However, the matching of renormalization schemes between different topological sectors was for a long time not well defined hence lead to ambiguity. In this talk we will also try to answer the question: If a vacuum sector Hamiltonian is regularized by an energy cutoff, how is the one-kink sector Hamiltonian regularized?
发布者： 发布时间：2024-10-14 14:14:16