In September, NYU Shanghai awarded its first ever Mathematics PhD. Qin Shuo, a Fudan University graduate, was also the program’s first Mathematics PhD candidate, joining soon after the program launched in 2018. “Honestly, it was a risk,” he said. Two factors helped him make the decision. One was that the program is jointly offered with NYU’s Courant Institute of Mathematical Sciences and confers an NYU degree. “Another key factor was that the three advisors accepting students at that time were all leading scholars in the field of probability theory,” he said. “For a PhD student, having the right advisor is incredibly important. The opportunity to learn from and even collaborate with top scholars made me feel the risk was worth it.”
Right: May 2024 @ NYU Shanghai, PhD Dissertation Defense
Qin’s studies spanned five years and three countries – China, France, and the US. “It was quite a unique experience,” he said. His first two years were spent at NYU Courant, before returning to Shanghai to conduct research under the guidance of his advisor, Professor of Mathematics Pierre Tarrès. The following year he left for Paris to be a visiting student at Sorbonne University, one of the world’s leading centers for probability research. In his final year, Qin returned to China, and leveraged NYU Shanghai’s resources to report on his research progress at partner research institutions both domestically and internationally. “I’m truly grateful for the cross-national, cross-cultural academic experience that NYU Shanghai has provided me,” Qin said.
Qin’s doctoral studies were in probability theory, a field deeply connected to real-world phenomena, and his research focused on “stochastic processes with memory.” “In simple terms, the evolution of such systems is influenced not only by their current state but also by the entire history of the systems,” he said. “Much like human behavior, we develop mechanisms based on past rewards or punishments, which in turn affect our current actions.”
Qin’s PhD dissertation focused on three subtopics within this area, the most significant of which is known as the “elephant random walk” problem, which refers to an imagined scenario of an elephant taking steps, sometimes randomly and sometimes repeating past steps. The study shows how historical behavior can significantly influence current and future actions in memory-driven systems. The findings also contribute to the theoretical framework of reinforced random walks. Qin’s paper on this topic, “Recurrence and Transience of Multidimensional Elephant Random Walks” was accepted for publication in Annals of Probability in September.
Qin expressed gratitude for his advisor’s continued support. “Professor Tarrès once told me that the only difference between him and me is that he’s senior and more experienced, while I’m younger with more time and energy,” Qin said. “This collaborative model allowed me enough time and space to explore and develop my own research style.Looking back now, I am grateful for that period of self-refinement.”
Beyond research, Professor Tarrès also mentored Qin as he explored his career options. “Before pursuing my PhD, I was relatively impatient, preferring to quickly complete tasks according to plan. But after working with him, I gradually understood the meaning of ‘more haste, less speed’—being in a rush wouldn’t spark inspiration,” said Qin. “Whether in my approach to life or research, Professor Tarrès taught me to treat both academia and life with more ‘grace,’ allowing enough time for thorough preparation and learning to handle multiple tasks in parallel.”
Having been NYU Shanghai’s first Mathematics PhD candidate and the program’s graduate, Qin seems not afraid to take on another “first” in his academic career. This year, he joined the Beijing Institute of Mathematical Sciences and Applications as a postdoctoral researcher, becoming part of the institute’s first cohort of Chern Instructors.