Bose-Einstein Condensate (BEC) is a super-fluid phase formed by atoms cooled to very close to Absolute Zero (about -273.15°C). At this temperature, the atoms get into a single quantum state (essentially behaving as one super-atom), and exhibit some really interesting phenomena. Now, Harvard University scientists (Lene Hau and group) have shown that these ultra-cold atoms can essentially 'freeze' and 'control' light, and form a processing unit of an optical computer :):). Optical computers would transport information ten times faster than traditional electronic devices (essentially at the speed of light), thereby smashing the intrinsic speed limit of silicon technology.

Stopped Light! (Courtesy: Hau's Lab)Professor Hau's group was previously able to slow down the speed of light (299,792,458 meters/second, or 186,000 miles/second, in vacuum) to about the speed of a bicycle, by using a cloud of BEC composed of sodium atoms. The same apparatus now is able to stop the motion of light alltogether! One applications of this could be in memory storage for a future generation of optical computers.
But the really striking discovery is that such frozen light can be used to do 'computations'!! The amplitude and phase of 'moving' light is smeared out over a distance (imagine a ripple on a lake). However, these characteristics are essentially frozen in stationary light, and thus can be used to a) store information (act as memory), and b) combined with amplitude/phase from other light particles (photons) to form rudimentary computational units (e.g. for addition and subtraction: just as two ripples sometimes form a bigger ripple when they cross each other). Combining many such units could one day lead to a true optical computer.
In addition to the beauty of such a structure, such optical processors will far exceed the capabilities of the electronic computers of today. Photons are much smaller than electrons, and carry no charge. Hence they can be packed in a much smaller space, thus perhaps leading to a higher density of such computational units than can be achieved in modern computers.
Hopefully, this century (and next) will belong to the quantum and the optical comptuers, just as the last one saw the rise of their electronic brethren :):).