Oppenheimer was a generous and engaged mentor to his flock of admirers. Discussions in class were often continued at his house, over dinner–often physics was left behind, as "Oppie" and his students drank, danced, and talked about art and literature late into the night. Many students even followed him to the California Institute of Technology, where he taught during the spring semester each year. Every April, these loyal Berkeley physics students would rent out their houses, pack up their cars, and drive up to Pasadena to listen to their beloved teacher lecture to his flock.
He was still the distant, arrogant man who had turned off fellow students in his New York high school, but he had a new charisma, a power of personality that led him to a level of success that he could never have attained with his physics skills alone.
Oppenheimer was still a practicing physicist, and he consistently published well-respected papers recording his gifted research in quantum physics. But while Oppenheimer was considered a good or even great physicist, it was clear that he did not rank among the world's top physicists. Despite expectations– those of his own and of his peers–Oppenheimer made no ground-breaking, cutting-edge discoveries, no lasting contributions to his discipline.
Although he never practiced world-class physics, Oppenheimer's years at Berkeley were far from fruitless. Working together with Ernest Lawrence, another Berkeley physicist who was also determined to elevate his department's reputation, Oppenheimer turned Berkeley into a world-class physics institution. Within two decades, American physics departments had taken their place among the world's top centers for theoretical physics, thanks, in large part, to Oppenheimer.