J. Robert Oppenheimer was an immensely complex figure, and the movie's based on a biography of him. While the movie is historically accurate in many ways, there are a few bits of fiction mixed in.

Nolan loves to tell a disjointed, stream-of-consciousness narrative, and Oppenheimer is no different ... contributions from Kenneth Branagh (Niels Bohr), Tom Conti (Albert Einstein), Josh Hartnett ...