Why did Harvard top mathematician Liu Jun leave the US for China?

When it was officially announced in late August that statistician Liu Jun had left Harvard University and joined Tsinghua University in Beijing, speculation ran rampant.

Was it political tension? Research funding cuts? A backlash against Chinese academics in the US?

For Liu, the answer is simple – and deeply personal.

It “has nothing to do with Trump”, he said in an email to the South China Morning Post, explaining that his decision was not out of political protest or professional disillusionment, but because of family and a lifelong bond with the Tsinghua campus where he was born.

On September 7, the Post published the story of Liu Jun’s return to China, which spurred heated discussions on social media and online forums, especially in the academic world.

Liu responded on September 9 to the Post’s email query.