內容：

Positive semidefinite (PSD) rank is a concept that was proposed recently to study the computational power of semidefinite programming, a problem in optimization theory. It turns out that it also has nontrivial applications in quantum information theory and even quantum foundations. In this talk, we will briefly introduce this quantity and its applications in device-independent quantum tasks. 

人物介紹：

Dr. Zhaohui Wei is currently a research fellow at the Centre for Quantum Technologies in Singapore. Before that, he received his PhD in 2009 from Tsinghua University. His main research interests are in quantum adiabatic computation, quantum error-correcting, quantum game theory, quantum correlations, and device-independent quantum tasks.