Classical computing of today depends on 0’s and 1’s to represent a bit state. A bit can either be ON=1 or OFF=0. This therefore means a bits effective efficiency is 50% as it represents either a 0 or a 1. This is the inefficiency that Quantum computing seeks to solve.
Quantum computing uses the principles of quantum mechanics to derive a system where, instead of a bit state efficiency of 50%, a bit state has efficiency approaching 100%. The close the bit efficiency is to 100%, the more possible states a bit state can assume, as opposed to only two in classical computing.
Quantum mechanics say that an electron is not the dot that used to trace a circular path around a nucleus in an atom as depicted in high school chemistry books, but that an electron is a short burst of a wave of energy.
These short waves of energy have different amplitudes, or sizes, but despite this, they are all electrons.
Quantum mechanics (according to the Copenhagen interpretation) also says that this short energy waves amplitude is the parameter with which we can measure the electrons presence at any spot in the universe. The amplitude has a direct correlation to the percentage probability of finding the electron when you look for it. confusing? hang on.
So each and every electron in the world has its own amplitude. This amplitude being also the percentage probability of finding that electron when you look for it somewhere. What does this mean? This means that all electrons are in several places at the same time and each spot of where it could be represents a percentage probability of it being there. Of course it will appear at the spot where it has the highest probability of being there, that is where its amplitude measurement matches the amplitude we are looking for. confusing?… hang on one once more.
So an electron that is observed somewhere has many other possible probable places where it could have been, but has appeared at the spot where probability = 100% and this is where its wave amplitude is a 1:1 match to the measurement expectation. This creates an unimaginable and mindbogglingly large number of possible places where it could have been. you should be getting the drift now…
Quantum mechanics again adds that this electron is capable of mimicking all these other possible probabilities if its excited by the right amount of energy. The electron can be here but also not be here (remember Schrodinger’s cat experiment?) Quantum computing research has been about getting this energy right and exciting these electrons to mimic these many possible probabilities of where they could have been and each probability represents a bit state.
So instead of a bit state being a 0 or 1 (with 50% bit state efficiency), with quantum computing, a bit state can be all the possible probabilities of finding that electron anywhere in the universe including where you are actually looking for it at that amplitude. That is a very large leap in possible ways in which computers represent data.
It does not end there…
With this very large number with us. We then take a group of electrons, measure their amplitudes and arrange them in a grid as below.
Because we know there is a 100% probability of finding electron E1 at the spot we have put if we look for its amplitude there, we can invert this amplitude to create an amplitude that cancels out E1’s amplitude to represent Zero. Find electron =1, not find electron there is anything between 1 and Zero.
A quantum computer does computations by looking at the grid above and placing electrons in them, measures their amplitudes, and uses it to store data bit states from 0 (negative amplitude) to 1 in very many steps that are equal to the probability of finding the same electron elsewhere in the universe. A Quantum computer can access all the electrons possible bit states at the same time and represent a 0 or a 1 at each possible state in each electron simultaneously. This is as you would imagine, speeds up computation speed drastically as the number of simultaneous computations is extremely large
A grid of 9 electrons above can represent a matrix with very many possible states of anything between 0 and 1 states. the number of electrons in a grid are known as qubits and each additional electron added to a grid doubles the computing speed.
To demonstrate how powerful a quantum computer can be, A computation that a quantum computer can do in 1 second would take 400 years to complete for our most powerful classical computer in 2020.
The ability to perform quantum computations would dramatically speed up and multiply our computing abilities in ways unimaginable and advance mankind towards General Artificial Intelligence. The dangers of quantum computing cannot also be ignored. One of cryptography’s underlying strengths is that encryption is done using numbers that are very hard to guess and for someone to decrypt a communication, they must know this number. There are ways to reverse engineer and calculate this number from encrypted data but this would take thousands of years to complete using our current classical computers. A quantum computer is capable of doing this reverse engineering computation in minutes. This ability will render current cryptographic techniques ineffective.Follow @tommakau