A vacuum - empty space - is not as empty as one might think. In fact, empty space is a bubbling soup of various virtual particles popping in and out of existence – a phenomenon called "vacuum fluctuations". Usually, such extremely short-lived particles remain completely unnoticed, but in certain cases vacuum forces can have a measurable effect.
A team of researchers have proposed a method of amplifying these forces by several orders of magnitude using a transmission line, channeling virtual photons.
"Borrowing" Energy, but just for a Little While