Short story about time travel with real physics. About his award-winning short story, Geoff writes, "'Ripples in the Dirac Sea' was an experimental story for me. Quite a number of disparate threads wove into the final narrative. One important thread was my feeling that a story involving time travel should have a nonlinear narrative to reflect the discontinuous way the characters experience time. I also wanted to see if it was possible to write a story in which real physics is presented. Very little of modern SF goes beyond the early quantum mechanics of Heisenberg and Schrodinger, work which is admittedly remarkable and beautiful, but by no means the end of the story. Here I tried to invoke some of the strangeness and beauty—I might even say sense of wonder—of the physics of Paul Adrien Maurice Dirac. In 'Ripples' I decided to explore the inconsistency between Dirac's relativistic quantum mechanics and the mathematics of infinity developed by Cantor and others (as far as I can tell, a quite real inconsistency). The Dirac sea is also real, not an invention of mine—despite the very science-fictional feel of an infinitely dense sea of negative energy that surrounds and permeates us."