Harvard's youngest Chinese full professor Xi Yin leaves OpenAI after only 5 months
Xi Yin, a string theorist and the youngest Chinese full professor in Harvard's history, has announced his departure from OpenAI. From reports of his joining in late May this year to his departure, roughly half a year passed. He said this was his first corporate job and that he will explore new directions. Yin entered the University of Science and Technology of China's youth class at age 12, was promoted to full professor at Harvard at age 31 in 2015, and has received the Sloan Research Fellowship and the 2017 New Horizons in Physics Prize; he previously estimated that, with extensive human supervision, AI sped up his research coding work by at least 100 times.
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OpenAI, it seems you can't keep people either.
Just now, the youngest Chinese full professor in Harvard's history, winner of the Sloan Award and the New Horizons in Physics Prize, and a star scholar in string theory—
Yin Xi, officially announced his departure from OpenAI.
From the news of his joining at the end of May this year to now personally announcing his departure, only about half a year has passed in total~
Regarding this departure, in his personal Twitter post, he gave this explanation:
This was a great journey, but I plan to get off early and explore new directions.
Yin Xi also revealed that this was his first corporate job.
He especially thanked Alex Lupsasca and Boris Alexeev for helping him adapt to the job, and also thanked Dan Roberts for his continued support. At the end, he did not forget to encourage his colleagues: "I will continue to cheer for you all!"
As for the next stop that everyone cares about most, Yin Xi has not yet revealed it. On the official website of Harvard's Department of Physics, his professor status is still listed.
Perhaps, maybe, it really might just be academic leave to experience life a bit.
Of course, some netizens directly named Discovery Loop, the AI company founded by former Google chief scientist Jeff Dean and others.
Where exactly he is going, let the bullets fly for a while first.
Who is Yin Xi?
Yin Xi entered USTC's Youth Class at age 12, obtained a PhD in physics from Harvard University in 2006, and was promoted to full professor at Harvard in 2015 at age 31, and has been called by many media outlets "the youngest Chinese full professor in Harvard's history."
He has long studied string theory, quantum field theory, and quantum gravity. In 2013 he won the Sloan Research Fellowship, and later, together with Simone Giombi, won the 2017 New Horizons in Physics Prize for research on higher-spin gravity and its holographic correspondence.
In April this year, before news of his joining came out, Yin Xi gave an interview to The Harvard Crimson and said directly:
Yin Xi estimated that, under extensive human supervision, AI still sped up his research coding work by at least 100 times—
Some research that was previously not even considered because the workload was too large can now be tried.
By September this year, the academic community launched another debate over what exactly AI will bring to mathematics.
Terence Tao and 25 other Fields Medal winners issued a joint statement expressing concern that AI companies treat conquering mathematical problems as a competition metric: there are more and more answers, but the process of understanding, organizing, and passing on these results cannot keep up.
Yin Xi clearly sided with those rebutting this view.
He retweeted mathematician Timothy Nguyen's response and said:
Among all the responses I have seen in the past few days, this is one viewpoint that I completely agree with and support.
Nguyen's opening directly stated: these Fields Medal winners' objections to AI will not stand the test of time.
His core point is that the way mathematics is understood has always been changing. From geometric constructions and symbolic computation to computer-assisted proofs, mathematics has always been expanding its toolbox.
Looking at it this way, although he is a human physicist, Yin Xi is not fixated on having humans stand at the center of scientific discovery. As long as the answers can withstand verification, he is happy to see AI run ahead first.
Basic scientists join model companies
When Yin Xi previously joined OpenAI, a group of top mathematicians and scientists had already gathered around him.
The black hole physicist Alex Lupsasca, whom he especially thanked in his farewell post, had already announced in October 2025 that he was joining OpenAI for Science.
Lupsasca said at the time: this team wants to build AI systems that can advance scientific reasoning and accelerate discoveries in mathematics and physics.
In addition, alongside the news of Yin Xi's joining, another figure also drew attention: Su Weijie, one of the "golden second generation" of Peking University's School of Mathematical Sciences.
In May this year, Su Weijie announced that during academic leave from Wharton School he would join OpenAI to participate in model training. At the same time, he was also officially promoted to full professor at Wharton.
Earlier, at the beginning of this year, Tsinghua Yao Class alumnus and theoretical computer scientist Chen Lijie had also joined OpenAI, focusing on mathematical reasoning.
Scientists bring research questions and the expertise to judge whether answers are good; model companies provide models, computing power, and engineering environments.
As for how Yin Xi views the relationship between AI and researchers, in that April interview he had already given a very clear answer:
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