A Pause in Space-Time (#1 in The Stasis Stories)

This novella length hard Sci-Fi book begins the “Stasis Stories,” a series of tales from the near future. They tell us about Kaem Seba, a sickly and financially destitute young man who uses his extraordinary math talents to work out a way to stop time within limited volumes of space-time. He and Arya Vaii, a business student, set out to develop the phenomenon.
It quickly becomes obvious that, beyond the fact that time stops inside the stasis field, the volume of space-time in stasis might be useful for some of its other phenomenal properties.
Since it essentially can’t be altered (time’s stopped inside) it’s stronger than any known substance and, unlike matter, does not melt.
This makes it the perfect material for building rocket engines. They set out to sell such engines in order to provide their budding business enough profit to let them develop other useful products.
Unfortunately, the owner of the lab that tested the properties of their samples also recognizes their potential. His desire to share in their profits unhinges his shaky grasp on reality. When he can’t talk them into letting him join their enterprise, he demands a share at gunpoint.