If the Casimir Effect is readily repeatable, one should, in theory, be able to collect a pool of negative energy. It has been postulated that where there is no energy, there is no space. So if you could collect enough negative energy, you could "punch through" the fabric of space-time and create a wormhole, called a PPT Tunnel in the book. Going through a PPT Tunnel allows you to go from Point A to Point C in zero time, mathematically going faster than the speed of light without violating relativity.
A fellow named Miguel Alcubierre Moya postulated the Alcubierre Drive which looks more like the Star Trek warp drive than my PPT Tunnel method of travel. But I thought the idea of coming to a dead stop so you could travel at many times the speed of light was more amusing. Later, MINIMCOM discovers how to create a continuous series of PPT Tunnels so that he never has to come to a stop. This method of travel does, indeed, resemble the Alcubierre Drive. In the novel The Ark Lords, OMCOM discovers how to apply the Casimir principle to negative energy, dividing it into real and imaginary negative energy, thus producing a null-fold. He adapts the null-fold into a stardrive which permits MINIMCOM to travel at an effective velocity of 15,000c which is pretty fast.
Most science fiction novels require the use of FTL drives to move the plot along because the stars are so damned far apart. I just wanted to pick one that had the greatest chance of happening some day. The Vuduri use negative energy, in the form of PPTs (nothing but miniature wormholes) to create weapons, generate electricity and communicate mind-to-mind.
To read another article that expounds upon the possible use of negative energy, click here.