In the past few decades, computer technology has grown and is continuing to grow at an exponential rate. Humans went from counting with their fingers just 200 thousand years ago to building machines that can solve differential equations. In the 1960s, humans were able to land on the moon for the first time because of computers. Now, in the 21st century, we are using computers to analyze and model complex mathematical equations. Computers are tackling problems that are crucial to our lives and human civilization. Not only that, humans have found a way to simulate intelligence in computers!
Despite all of its success, our current computer technology is going to encounter problems in the future. But don’t worry, a new type of computer technology is slowly emerging. Scientists are testing and attempting to develop quantum computers.
Quantum computing is in its very early stages. But in order to understand quantum computing, you must know the basics of current computer technology and quantum mechanics.
In short, computers essentially process information. The reason they were made is that they process information faster and better than humans. Well, how do they process information? Computers contain devices called transistors which are basically switches. When electricity passes through a transistor it’s turned on and when there is no electricity the transistor is turned off. Furthermore, the number “1” represents on and “0” represents off. Transistors allow us to control the flow of electrons (electricity) and when we have a bunch of transistors that are turned on and off we produce a bunch of “0”s and “1”s. These individual “0”s and “1”s are called bits. Nowadays, computers usually have billions of incredibly tiny transistors (they control the flow of electrons, sometimes just 1, so they have to be super tiny). Due to so many transistors, we can process a lot of information through “0”s and “1”s.
Now that the fundamentals of computer technology have been explained, the next thing to “understand” is quantum mechanics . Notably, the most popular interpretation of quantum mechanics is the Copenhagen interpretation. It basically says that a particle does not exist in one state, but in all possible states at the same time. For example, a particle can have a position, velocity etc. But we won’t know exactly the values of those things. This idea of particles existing in all states is called superposition. However, once we observe or interact with the particle, its superposition “collapses” and it assumes one state. A famous example is the uncertainty principle. It says the more accurately we measure the velocity of a particle the less accurately we can measure its position and vice versa. Basically, we can never know exactly both the state of the velocity and position of a particle at a given time.
To sum up, computers process information by creating bits through switches controlling the flow of electrons. The Copenhagen interpretation says that particles (e.g. electrons) can be in multiple states at once and we won’t know exactly what state it’s in unless we observe it.
Combining both of those ideas, quantum computers use qubits. Qubits are particles that have 2 possible states, represented by “0” or “1”. Due to quantum superposition, before observation/interaction they are in both states at once. Once we put that particle through a filter similar to a transistor we will know the exact value/state of the particle. This is an extremely powerful idea. In a classical computer, 4 bits can have just 1 combination at a time. But in a supercomputer, they can have (2*2*2*2) or 16 different combinations at the same time since each bit (particle) exists in 2 possible states.
Quantum computers can do calculations extremely fast since they can test a huge amount of values at the same time (due to superposition) to check if they are right or wrong. They can factor huge numbers and figure out if a number is prime much faster than a classical computer. Quantum computing has a lot of potential due to its power and speed. It has the possibility to simulate quantum and molecular phenomenon very accurately. However, quantum computing is its early stages and scientists are only able to perform simple calculations with quantum computing.
Unfortunately, we won’t be using quantum computers like personal computers anytime soon but it’s a very promising technology. I find particle physics an interesting subject so it’s really cool to see a new application emerging from it in computing technology. Overall, quantum computing is a very fascinating subject with the potential to change the world.