Like the atomic particles he studies, Pablo Ducru seems constantly on the move, vibrating with energy. But if he sometimes appears to be headed in an unexpected direction, Ducru, a doctoral candidate in nuclear science and computational engineering, knows exactly where he is going: “My goal is to address climate change as an innovator and creator, whether by pushing the boundaries of science” through research, says Ducru, or pursuing a zero-carbon future as an entrepreneur. It can be hard catching up with Ducru. In January, he returned to Cambridge, Massachusetts,…