Hi everyone, I had a related, more complicated post in another thread - I hope it's ok to post a simplified and slightly different question here (posting as a layman): Let's say I have an electron traveling alone in the vacuum, when a vacuum disturbance (fluctuation) occurs nearby. If the disturbance has the correct form, say, an electron-position pair, could the positron annihilate with the original electron? (leaving the remaining electron) The positron would have to have negative mass to ensure conservation of mass/energy. So, the overall question, could something like the above occur? I've been careful to specifically stay away from the term virtual particle. Any help would be greatly appreciated, as I think there are a number of concepts I'm getting confused. Thanks all!