What’s Moore’s law? It states that every 18 months or so the computer power of a silicon chip doubles. But, how long do you think it can go on, right ? The computing efficiency of a silicon chip based computer is already on the verge and the rate is slowing down and within 10-15 years from now it will be a flat line. Why? because of overheating of the chips. When the number of silicon atoms used will reduce up to a thickness of 5 atoms of thickness or near, the chip will overheat and destroy itself in the process and as we go down to that extent the quantum phenomenon of the electron would take over and it wouldn’t be bound to a restricting path but it could be anywhere. Therefore we would not be able to do precise calculations anymore. It would be the end of Moore’s law. We no longer would be able to keep up with it using silicon chips in out computers. There would be a huge recession for sure in that period.
Don’t worry though because new candidates are coming up in order to replace the silicon chips. One of them is molecular computers. Do you know how many atoms are required to make up a single bit of memory in our ordinary memory drive ? It takes more than a million atoms; well that’s not that shocking right ! But recently IBM has managed to store a single bit of memory in exactly 12 INDIVIDUAL ATOMS. Yes only with 12 atoms. The ratio to the size of today’s memory bit is ~ 0.000012 time. But the problem with this is its very complicated to built at that scale. Building circuit in that small scale isn’t that easy. But, even with this problem we might be able to make computers with a larger number of atoms. Getting down to the size of atoms in order to compute a problem doesn’t seem like a far stretch any more. We are almost there and you can probably guess the sizes of the supercomputers in the next decade. But getting down to still smaller number of atoms create a huge problem with coherence. The coherence from outside like any kind of small vibrations can even disturb their state and would result into random rubbish in output. But, there is hope. At least we would be able to see molecular computers in the next few decades. This Picture here is taken by a Scanning Tunneling Microscope which can even interact with the atoms individually.
And here’s a model showing how they interact with the magnetic fields of the atoms.
And as you would have heard Quantum Computing has recently gained some popularity among physics enthusiasts. This can use the polarization of a single photon based on the direction of its polarization to store a single bit of date. But as it is in quantum state we would be able to attain a superimposed state i.e. both 1 and 0 at the same time. You might think that’s confusing, how is it going to give us the correct result then ? right ! But, you see when you would be able to attain a state of superposition, we would be able to perform a task with several results. What I mean is previously we used to allot a certain work or response to only two results i.e. 0 or 1 but now we would be able to respond to different polarization angles as well so we can attain any number in between 0 and 1 too. So, there will be an infinite number of responses we can perform according the the signal or information we get from a single polarization of a photon. So think of it this way; if we had to choose the correct path out of a maze which had a millions of possible paths but only one led you out, then a quantum computer can simultaneously will be able to test every possible path there is and will instantly give you the correct path; which a computer would do checking every path one by one. It gives us the ability to compute every possible outcome at a single go which a today’s computer has to do one by one.
But this is a far stretch though. Because, the biggest calculation we have been able to do with just five numbers of atoms (no where near photons) is ‘3 x 5=15’. So you can see how far we have to go. The same advantage of being able to attain more than just two possible outcome in a bit has become its greatest demerit too making it nearly impossible to engineer. To architect a system which can solve problems using these phenomenon will be a revolution in itself and whoever will successfully do that will be the inventor of the century. And let me remind you that we are no where near to make this possible. There is another big hurdle in the way i.e. decoherence. The smallest of vibrations even daily activity like putting the cup on the coffee table or walking near the apparatus is disturbing the synchronization of the atoms. So it is very difficult to maintain their stability. These reasons are what’s making this awesome technology very impossible to make. I hope we would be able to see this technology in my lifetime who knows maybe before the end of this millennium. But, don’t worry even if we won’t be seeing quantum computers in coming decades we might see molecular computers though. Look to two decades ahead and we might find ourselves with molecular computers in our hands and so much better and efficient than today’s technology.