You might not have to look too far to find what you need to dress as the "father of the atomic bomb," J. Robert Oppenheimer, played by Cillian Murphy in Christopher Nolan's biopic. To embody the film's titular physicist, you'll want to obtain Oppenheimer's signature brown fedora as well as a vintage, professorial suit or trench coat. If you want to make an "Oppenheimer" costume into a joint effort, Albert Einstein also makes for a fun and easy choice — just locate a flowing white Einstein-style wig and you're all set.