If there was only a gateway for atomic sized materials you can send INFORMATION and replicate your civilization, members, history and data on the other side as well.
Kaku mentions sending nanobots. Information alone wouldn't do it, I think. There must be an actor of some sort to instantiate the information on the 'other side' (if there is an 'other side').
Of course, I was referring that in addition to nanobots, a civilization could send it's library, genetic library and other databases as well as the nanobot. Next time I will be a little more precise with the language.