Arguably, "creativity" plays an important role in all intellectual work, and is more important and easier to achieve the closer you get to the cutting edge of a subject. I don't think that there's anything special about creativity; It's just that the higher your expertise is in whatever it is you work with, the harder it is for people who have a lower level of understanding of the subject to understand how you come up with your ideas, and what it is that you see that they don't, and therefore they think that you're creative. I think one of the most important skills to develop as any kind of intellectual person is the habit of actively and deliberately exploring alternative ideas and their consequences.
So my answer is: Obsessiveness, curiosity, and playfulness.P.S. I'm not a physicist.