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)
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 :):).
Stopped Light! (Courtesy: Hau's Lab)
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 :):).
Frozen Light
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Theoretically, say the first photon has amplitude A1 and phase P1. The second has amplitude A2 and phase P2. When these two interfere, you get a new photon with amplitude A1*cos(P1)+A2*cos(P2)! If P1 and P2 have suitable values, you can simulate addition (A1+A2), or subtraction (A1-A2).
Once addition and subtraction can be done, you can do every other operation.
The heat produced should be less, as a lot of heat in current processors is due to electron scattering, which is partly because electrons carry a charge. Photons are chargeless, so should create less heat. Also, since the setup is at near absolute zero, and nothing much is moving, makes heat generation pretty low!
:-D:-D.
Perhaps it is helpful to imagine a point of light, hanging in the air?
This memory cannot work persistently.
To put it another way, once the plug is pulled, the state of the memory is lost.
So this kind of thing couldn't function like some of the other memory types you use in common electronic devices like mobile / cell phones and the like...
a) First remove all the faster atoms in the gas. That reduces the temperature quite a bit.
b) Slowly confine the remaining atoms in a smaller volume (by magnetic traps)
c) Hit them with lasers, which carry away energy on reflection.
"If these two technologies are combined, we'd soon see the emergence of mainframe-sized computers able to do more than all the computers out there today."
Yup! Then there are spintronic devices that will be soon on the market... so this century will belong to quantum computers, holographic storage, and brand new fields such as spintronics, superconductive electronics, and so on :-D.
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