原子和光物理学1-第3部分：原子-光相互作用1-矩阵元素与量子场

Founded by Tsinghua University in October 2013, XuetangX is the world’s first Chinese MOOC platform and serves as the research and application platform for the Ministry of Education (MOE) Research Center for Online Education. XuetangX has been awarded as one of the national first batch of demonstration base projects for innovation and entrepreneurship. Besides, XuetangX also works with the International Center for Engineering Education (ICEE) under the auspices of UNESCO and supports its online portion. By the end of June 2018, with a total of 25 million enrollments and more than 1,500 online courses from 13 disciplined fields, XuetangX has accumulated over 12 million registered users, covering 209 countries and regions.