When a researcher from a Chinese military academy applied to study with celebrated Boston University physicist Eugene Stanley, he said her affiliation didn’t raise red flags.“I’m not interested at all in politics. I’m a scientist,†said Mr. Stanley, whose wide-ranging research has included using artificial intelligence to decode financial markets and applying statistical physics to prevent diseases.The recent indictment of the researcher, who is accused of lying on her U.S. visa application to conceal she is a lieutenant in the Chinese military, shows how U.S. universities’ openness to international collaboration in cutting-edge research leaves them vulnerable to potential exploitation.Mr. Stanley...