“It sounds like a headline from the spoof newspaper The Onion, but for physicists, this is actually an achievement: Two teams have stored nothing in a puff of gas and then retrieved it a split second later. Storing a strange form of vacuum builds on previous efforts in which researchers stopped light in its tracks (ScienceNOW, 22 January 2001) and may mark a significant step toward new quantum information and telecommunication technologies.
To stop light, researchers first shine an intense and continuous beam of laser light into a gas of atoms. That “control beam” tickles the atoms to allow a pulse of laser light of another wavelength to enter the gas. To trap the pulse, researchers turn off the control beam, which causes the pulse to imprint itself on the atoms. To release it again, they turn on the control laser.
So storing a vacuum might sound ridiculously simple: Follow the same procedure but leave out the pulse, and you store nothing. However, Alexander Lvovsky of the University of Calgary in Canada and his colleagues and Mikio Kozuma of the Tokyo Institute of Technology in Japan and his group have stored a very peculiar type of nothingness called a “squeezed vacuum.”
(via Science Now)