The Q-cohomology of four-dimensional N=4 super Yang–Mills theory provides a powerful framework for studying supersymmetric states and the microscopic origin of black hole entropy in AdS₅. In this talk, I will review recent progress in understanding this cohomology, focusing on the distinction between monotone and fortuitous states. While monotone states persist as the rank of the gauge group increases, fortuitous states arise from finite-N effects and are believed to play an essential role in accounting for black hole microstates. I will then discuss how quantum corrections modify the classical Q-cohomology, and what these corrections imply for the structure and fate of supersymmetric states. Together, these developments offer new insights into the emergence of black hole entropy from gauge theory.

Biography

Chi-Ming Chang is an Associate Professor at the Yau Mathematical Sciences Center, Tsinghua University. He received his bachelor's degree from Tsinghua University in 2006 and his Ph.D. from Harvard University in 2014. He held postdoctoral positions at the University of California, Berkeley (2014–2016) and the University of California, Davis (2016–2019), before joining Tsinghua University as an Assistant Professor in 2019. He became an Associate Professor in 2025. His research focuses on quantum field theory, string theory, and quantum gravity, with particular interests in black hole microstates, non-invertible symmetries, and holographic dualities. 

Inviter: Gang Yang