http://en.wikipedia.org/wiki/Antimatter
first paragraph, last sentence.
i guess they also produce other particle, antiparticle pairs but i'd imagine they would annihilate each other as well within Planck time.
So apparently vacuum energy is created and destroyed within Planck time by matter, antimatter annihilation. If someone could theoretically stop or slow down time, would it be possible to tap into vacuum energy? Since annihilation creates gamma rays, I suppose vacuum energy would face the same...