I certainly missed this one, which is understandable because it was uploaded in a section of ArXiv that I don't normally read.
On the day that Steven Chu was undergoing his confirmation hearing for the Secretary of the Dept. of Energy position, his research paper was posted on ArXiv by one of his co-author. Not that this is a surprise considering everything we know about him already. Besides, this was done when he is the Director of Lawrence Berkeley Lab, and it is not unusual for a Nat'l Lab director to still continue doing physics research work.
Still, I wonder how much of this can he still do after he becomes the head of DOE. Will he have time to continue doing or be involved in research work, even on the peripheral? Can it also be a conflict of interest? Or maybe he'll work alone and produce papers more on ABOUT physics, rather than physics itself, such as the one done by the out-going Presidential Science Advisor John Marburger.
In any case, he will have his hands full, that's for sure.