**Lecturer: You Jiangong**

**Abstract:**

Phase transition means that when the physical parameter of the system change, the physical properties of the system suddenly change at a parameter point, and the parameter point is called the phase transition point. Mobility edge means that the existence of different energy regions in a determined physical system makes particles in different energy regions show different motion states, and the boundary point between these regions is called mobility edge. Phase transition and mobility edge are important research objects of quantum physics. Mathematically, this corresponds to the sudden change of spectral properties of Schrodinger operator with parameter or energy. The lecture will briefly introduce the research progress in this field.

**Introduction to the Lecturer:**

You Jiangong received a doctorate from Peking University in 1989 and is now a professor at Chern Institute of Mathematics, Nankai University. He has been committed to developing mathematical theories and methods for dealing with small divisor resonance for a long time. He has made a series of achievements in the undisturbed reducibility theory of quasi-periodic linear system, spectral theory of pseudo-periodic Schrodinger operator, regularity of Liapunov exponent, KAM theory and its application in differential equations, and issued more than 60 papers in international famous academic journals such as*Invent. Math.*,*Duke Math. J*,*GAFA*and*PRL*. He has won the first prize of Natural Science Award of the Ministry of Education, the second prize of National Natural Science Award, and the Outstanding Youth Scholar, by Hongkong Qiushi Scientific and Technological Foundation. He was supported by the National Science Fund for Distinguished Young Scholars. In addition, he was invited to give a 45 minute academic report at the 2018 International Congress of Mathematicians.

**Invitee:**

Hu Xijun, Professor from School of Mathematics

**Time:**

16:30-17:20, November 25 (Thursday)

**Venue:**

Academic Hall #924, Block B, Zhixin Building, Central Campus

**Hosted by School of Mathematics, Shandong University**