The Genesis Machine, a novel by James P. Hogan - his first hardcover. Here's the flap copy for plot set-up:

Brad Clifford's theory was just applied mathematics - but its implications were too hot for the frozen minds of his superiors to grasp. So they buried it - and him - under wraps of secrecy.

Then Aubrey Philipsz, iconoclast and fellow genius, appeared on the scene to build the Genesis Machine that Clifford's theory made possible. And all previous science and technology went into a tailspin.

Suddenly, all weapons seemed useless before the previously unimagined power of the Genesis Machine. It could wreck a world or save it - and the men who ruled that world on a path of disaster now fought to gain control of this new force.

But Clifford and Philipsz had another goal, another dream.

They were reaching for the stars!