Vacuum to Antimatter-Rocket Interstellar Explorer System (VARIES)
An Interstellar Rendezvous and Return Architecture
Recent research shows that, with a sufficiently powerful laser (of the type we're close to building), it would be possible to actually generate particle-antiparticle pairs from the vacuum of space itself, by providing these virtual particles with sufficient energy to make them real. It's the same principal behind Hawking radiation - only Hawking uses the gravitaional energy of a singularity instead of a laser.
The idea is to build a spacecraft with inflatable solar panels that would go into quite close orbit around the sun. The panels would charge either supercapacitors or quantum batteries, and discharge an extremely powerful laser, in the peta or exawatt range. This laser would create matter-antimatter pairs from the vacuum and store it as antihydrogen, which would later be annihilated for propulsion.
One critical and unique component to the VARIES architecture is the proposal that proton- antiproton pair creation can be generated from the vacuum, given a sufficiently powerful electric field. An electric field is known to make the quantum electrodynamic vacuum unstable, which decays by emitting bosons or fermion pairs [Sauter, 1931; Heisenberg, 1936; and Schwinger, 1951]. In terms of Feynman diagrams, vacuum polarization can be represented by a fermion loop, as in Fig. 2. It is possible to associate a mathematical expression with the graph, and, for a critical electric field strength, real particle-antiparticle pairs are created via absorption of the photon by the vacuum.
Spontaneous particle creation from the vacuum by an external electric field has been applied to numerous problems in contemporary particle physics, including black hole quantum evaporation [Hawking, 1974; Damour, 1976; Gibbons, 1978; Gavrilov, 1975] and electron- positron creation in the vicinity of charged black holes [Damour, 1976]. Numerous papers in the literature indicate that it is possible to construct lasers with sufficient power to spontaneously produce electron-positron pairs from the vacuum [Ringwald, 2003].
What does this mean in practical terms? Basically, it would be possible for an interstellar spacecraft to create it's own fuel - and the most powerful fuel it's possible to have - from nothing more than sunlight and empty space. There are a few minor technical hurdles to overcome, such as containment of the antimatter, storage of the energy required for lasers... but in principal, it seems like a workable scheme.