Quantum Distortion, as stated by Alicia, occurs in regions of empty space where matter randomly appears and vanishes as a result of intense magnetic fields. One place where such a phenomenon has been theorized to occur is near a neutron star, a star filled with subatomic particles know as neutrons, which have no electrical charge.
If a spacecraft where to approach the speed of light, it would be hindered by Einstein's famous equation , Energy equals mass times the speed of light squared, namely the energy it took to propel the craft would be converted to mass, and then you would need more energy to propel the "weight of the craft" as well as new added mass (relativistic mass), and so on and so forth down the line. In other words, General Relativity (science of very large objects) states that space and time are fused and that nothing can travel faster than the speed of light. One way around this as stated, would be a space-time or warp bubble, that is the space (or space-time) is shorten or compressed in front of the craft and expanded in "the back". As a result, the ship could travel at many times the speed of light while the ship itself sits in zero gravity, meaning the crew don't end up as a grease stain on the aft bulkhead from the acceleration. This end-run still begs the question, which is where is the energy for all of this. That is where negative energy comes into play. Empty space is filled with all sorts of fields: gravitational ones set up by the mass of surrounding objects, electromagnetic ones from stars and other light-emitting things, and even quantum jitters of subatomic particles flickering in and out of existence too quickly to see (These particles are called virtual particles.) These fields fill space with energy. Even if gravity and electromagnetic sources are removed, the virtual particles persist. Quantum mechanics, the science of the very small, has taught us that even empty space contains energy. In this context, "Negative energy," therefore, is the state of having less energy than empty space. And that's where things get hard. Nobody knows how to get less energy than empty space. If we knew how, we could exploit that energy difference and have limitless power (The idea is called zero-point energy). Regardless, the Alcubierre warp drive, which would use negative energy to create a warp bubble that could be used to counteract the positive energy that would be needed to initiate the bubble creation. In essence, the negative energy would cancel out some of the positive energy needed, reducing the overall energy requirements.