There's a nice trove of Greg Egan stories on Free SF Online, and for the past few days I've been reading The Planck Dive, a 1999 Hugo nominee. Egan writes the hardest of hard SF--as with Gregory Benford, he is a practicing physicist. Egan goes even further than Benford, sometimes attempting to explain String Theory, even.
The Planck Dive goes very deep in this sort of explication, at the expense of the narrative. Really, the story part doesn't even make much sense, and didn't grab me at all. The story itself is 2 stars at best. But I bump it up a notch for this particular version, which includes very good background material on the physics involved. So as a textbook, I'll give it 3 stars