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Most people have probably heard the word “Quantum Computer” thrown around in conversations, a futuristic technology that will change computers forever. But how do they work? What does it even mean to be “Quantum”? And when will we actually see them? I don’t exactly have a release date for you, but the general timeline may be closer than you think.
If you’ve been alive for the time where the internet has existed, I would guess you have a vague idea of how computers work. When it comes down to the very basics, computers store bits, simple 0’s and 1’s, and perform operations on them to change and use them. They can be used to do anything from addition to your favorite video game. To make our computers run faster, we have been shrinking the parts, which allows us to fit more of them, but this brings challenges. As we get smaller, quantum physics can mess up what worked in the normal world. Imagine you have a barrier that is stopping an electron carrying data from passing. This would work in the normal world, but as we get smaller, quantum physics could just make that electron pop right through the barrier. This would mess up our computation, and presents a large issue with shrinking parts.
Despite this, quantum physics is not completely negative for computing. As I mentioned before, traditional computers use bits to store data, which can be a 0 or a 1. The quantum equivalent is the qubit (quantum bit), which also can be a 0 or a 1. However, qubits do not necessarily have to be one or the other. In the quantum world, there is a thing called superposition. Superposition means that something has two possible states, but isn’t necessarily one or the other until it is observed in which case it chooses, and collapses down into just one. As an example, if you have 5 traditional, binary bits, they can be in 1 of 32 possible states. Not bad, but consider what you could do with 5 quantum bits. They can be in all 32 states at once. Another property that comes from quantum physics is entanglement. Two quantum particles can be entangled, which means that one of their states is completely linked to the other, so by observing one and collapsing it, the other’s state can be instantly determined. Using these properties cleverly will allow for much faster processing.
One field this would be particularly useful in is searching through databases, where using various quantum mechanics, it would take only a square root of the time to search a database. As the size of a database gets larger, you see how crazy this is. 1,000,000 operations could be cut down to only 1000. A specific example of where this could be a problem is in cryptography, and the security of a computer. Your computer encrypts data by using a public key, which is available to anyone, and your own private key, which only you have. The public key allows people to encode messages and send them to you, and using your own private key you can decode it and see the information. The issue is, these keys are linked in a way, and with the computing power of a quantum computer, what would take our ordinary computers years to find could be significantly cut down to a reasonable amount of time. Don’t worry though, people are actively trying to find ways to avoid this, and are developing encryption systems that will be safe from quantum computing. But when exactly will quantum computers be around?
Now, nobody knows exactly when quantum computers will come about. However, we are getting closer. Recently, researchers at the University of Innsbruck managed to entangle two atoms over a distance of 230 meters. This may not seem very long, but our previous experiments with this have only been a few meters apart. To conclude, quantum computers will probably not be around for some time, and definitely not as home computers. However, the concept and mechanics behind them are there, and perhaps they will exist in some of our lifetimes.