Desperate to locate and re-read exceptional book/series, but cannot remember the title.
The high concept: The U.S. has just sent the first successful expedition to Mars, and it has just landed. As the astronauts make their initial exploration outside their ship, a tear in the fabric of space opens up right in front of them, and they look through to the insides of a laboratory (at a California university?) and two students who just figured out how to create arbitrary portals between two points in the Universe.
The rest of the novel/series is a consequence of this breakthrough. But I can't remember the author and title(s). Surely someone reading this forum will remember it well! TIA.
(Reposted from the SFSite F&SF forums.)