Moore’s Law tells us that every couple of years the number of transistors in a microchip double, but as transistors become smaller and smaller, quantum physics creates a limit to the size at which they can work. Essentially, transistors are an electric switch, controlling the flow of current. The switch can be turned on to let electrons through, or the switch can be turned off to block electrons. This on or off state of the transistor creates the binary system (1’s and 0’s) which is essential for the functioning of computers.
An important part of the transistor is the depletion layer. A part of this layer is negative, acting as a barrier, repelling electrons and stopping electric current. Stopping this flow turns the transistor off. But, by applying a positive voltage, this negative charge can be overcome, and electric current can flow, turning the transistor on.
As transistors become smaller, this depletion layer is no longer an effective barrier. In classical physics every particle has an exact position and momentum. However, in quantum physics the particle does not move on a trajectory; its place in space is described by a distribution of probability. This means that when the depletion layer becomes thin enough, quantum particles like electrons can undergo quantum tunneling and appear on the other side of the barrier. This means that one day Moore’s law will no longer apply because the depletion layer, and therefore also the transistor, can only become so small.
Quantum computing could be the solution to sustain the yearly improvement of our computers power. Unlike traditional computers, quantum computers do not use transistors. So, instead of having bits which can only have 1’s and 0’s, quantum computing works with qubits which can simultaneously represent 1’s and 0’s. This property of qubits makes quantum computers incredibly powerful.
This power could be used to quickly create highly trained AI (artificial intelligence). AI needs to process huge amounts of information to evolve, learn and gain experience in a field. For example, AI has already been created by showing thousands of images tumoral samples so that it can learn to identify cancer and make diagnoses. But, due to limited computer power, this AI software is not 100% effective and can misdiagnose patients. With the help of quantum computers, AI’s which help to find cancers could process far larger data sets and increase their accuracy.
One area that quantum computers will without a doubt change is the world of encryption. One of the most common forms of encryption is called RSA. It works by locking messages using a larger number (n) so that the only way to decode and access that data is knowing the factors (p and q) of that number. And since p and q are both prime numbers, n has only one possible value. If somebody does not have these factors, they can either not access the data or they need days going through millions and millions of numbers. Whereas quantum computers are far more powerful than traditional computers and can have faster operations. This would render IT security obsolete and significantly affect embassies, military, governments and any other organisation that needs to hold the messages it sends a secret.
Quantum computers create endless solutions to the problems of our time, but it would be reckless to discount the risks they could pose. A new age of technology is about to start; we must make sure that we are not caught off guard.