重庆大学物理系与中国科学技术大学天文系将于2021年4月16日至4月20日在重庆举办2021年度重庆大学－中国科大宇宙学青年学术研讨会：物理宇宙学的新视野，在此诚邀各位老师和同学们参加。
The Department of Physics at Chongqing University (CQU) and the Department of Astronomy at the University of Science and Technology of China (USTC) will host the CQU & CfA@USTC Junior Cosmology Symposium: New perspectives on physical cosmology from April 16 to April 20 of 2021 in the city of Chongqing. All scholars in fields of physical cosmology are most welcome.
为了促进相关领域青年学者的学术交流，特组织召开此次会议。本次会议以口头报告以及墙报的形式研讨交流物理宇宙学的新视野相关课题，充分研讨交叉领域的研究现状、重要问题和未来发展方向，展示最新研究成果和进展，以及探讨如何推进中国青年学者在物理宇宙学领域的进一步发展和科学合作。
In order to improve the academic exchange of young scholars in relevant fields, we organize this symposium, during which we will address various topics of physical cosmology in forms of oral presentations and posters.
本次会议不收取注册费。会议期间，住宿与交通请参会人员自理。
There is no registration fee for the symposium. All travel and local accommodations will be covered by the participants.
会议注册截止日期为3月31日，已盖章的会议通知请在这里下载。
The symposium can be registered by March 31. The notice can be found here for your convenience.
会务组：蔡一夫（主席），方文娟，李明哲，李昕（主席），拉丽萨，邱涛涛，赵文，郑云龙
Organizing committee: Yi-Fu Cai(Co-chair), Wenjuan Fang, Mingzhe Li, Xin Li(Chair), Taotao Qiu, Larissa Santos, Wen Zhao, Yunlong Zheng
资助单位 Sponsors
重庆大学物理系 Department of Physics, Chongqing University
星系和类星体创新群体 The NSFC "Galaxies and Quasars" Innovation Group
中国科学技术大学天文学系 Department of Astronomy, USTC
中国科学院星系宇宙学重点实验室 CAS Key Laboratory of Cosmology and Galaxy
国家自然科学基金委阿里项目委主任基金 The NSFC Director Fund for AliCPT
中科大交叉学科理论研究中心 The Interdisciplinary Center for Theoretical Study, USTC
华中师范大学天体物理研究所 Institute of Astrophysics, Central China Normal University
扬州大学引力与宇宙学研究中心 Center for Gravitation and Cosmology, Yangzhou University
会议背景 Background
2019年诺贝尔物理学奖花落天文学，其中一半授予了天文学家James Peebles，表彰他在物理宇宙学方面的理论发展。而进入21世纪以来，宇宙学领域已经斩获四次诺贝尔物理学奖，分别是宇宙背景探测者卫星、宇宙加速膨胀的发现、引力波的探测，以及2019年的此次诺贝尔物理学奖，这使得现代宇宙学获得了广阔的发展前景。因此，物理宇宙学引起了科学界的研究热潮和民众的极大兴趣。然而，随着天文观测数据的不断累积，通过不同的观测窗口针对同一个宇宙学参数的实验检验逐渐为我们呈现出来更为丰富的动力学细节。尽管基于广义相对论和宇宙学原理所建立起来的标准热大爆炸宇宙学模型仅用6个参数就完美解释了目前所有的宇宙学观测数据，不可忽视的是一些宇宙学危机正在悄然来临。
The Nobel Prize in Physics has been awarded to the developments of astrophysics in the year of 2019, of which half was awarded to the cosmologist Professor James Peebles for his magnificent contribution to the theoretical developments of physical cosmology. Nowadays, the study of physical cosmology has been the hot topic in the scientific community. Along with the accumulated observations of high precision astronomical experiments, the data of cosmological parameters through various observational windows have presented us fruitful details about their dynamics. While the standard paradigm of physical cosmology has successfully explained almost all cosmological data merely using 6 parameters, it is crucial to notice that some cosmological tensions may arise.
描述当前宇宙膨胀速率的哈勃常数H0，通过正向距离阶梯（利用银河系内造父变星几何测距加上近邻星系变星周光关系）测量得到的值和用反向距离阶梯（指用宇宙微波背景辐射测量作为基准，用声学视界作为标尺结合宇宙学模型反推H0）推断出的结果并不完全一致。欧空局的Planck卫星测量结果和Adam Riess团队结合Gaia测量得到的H0差异置信度已经达到4.4个sigma。此外，描述宇宙中物质比例的参数（Omega_m）和描述原初密度扰动程度的参数（sigma_8，原初密度扰动在8 Mpc/h尺度上扰动的均方根）的宇宙微波背景辐射测量和弱引力透镜测量结果也不尽一致。尽管目前弱引力透镜测量方法还刚刚起步，其中的系统误差分析有待改进，这也意味着二者测量差异的置信度还不算很高，但随着越来越多天文项目对宇宙大尺度结构巡天的高精度检验，这一问题变得非常重要。这些危机的存在给宇宙学家带来了极大的困惑。
One recently-well-debated tension relates the value of the Hubble parameter at present time, H0, which depicts the expansion rate of our Universe today. Its value derived from the Cosmic Microwave Background (CMB) temperature and polarization data by the Planck satellite differs from that determined by local measurements of the distance-redshift relation with a statistic significant above 4 sigma. Another potential tension concerns the measurements of the parameter sigma_8, which quantifies the gravitational clustering of matter from the amplitude of the linearly-evolved power spectrum at the scale of 8 Mpc/h. Specifically, a possible deviation was noticed between the measurements of CMB and LSS surveys, namely between Planck and SDSS/BOSS. Nevertheless, the statistical confidence of this cosmological tension remains low and is not as manifest as the H0 tension.
这些宇宙学危机出现的原因何在目前还尚未解答，究竟是测量误差还是新物理，大家众说纷纭。但无论如何，揭开真相都对物理宇宙学的发展至关重要。如果是测量误差，那么我们就需要重新审视当前所依赖的宇宙学观测手段，以及寻找新的宇宙学观测独立窗口，例如基于引力波探测技术所孕生的标准汽笛宇宙学；如果是新物理，那么我们需要给出详细的动力学描述，并进一步寻找超出标准图像的新宇宙学模型。
Although these cosmological tensions could in principle arise from unknown systematics which expects new and independent observational technology such as the standard siren cosmology based on the gravitational wave experiments, the possibility of physical origin puts the standard lore of cosmology into additional investigations, by pointing to various extensions beyond the standard paradigm of physical cosmology.