By Muhan Sun

The term quantum computing conjures up images of futuristic computers, more powerful than anything we can currently fathom. But what exactly is this concept all about? What will quantum computers be capable of?

Function and Advantages

To understand how a quantum computer works and the advantages it offers, we need to first briefly take a look at how an ordinary computer looks, mainly how it stores its information. In an ordinary computer, information is stored and processed in what is known as binary, meaning that all the information is represented as a series of 0s and 1s, with these in turn representing the state of an electrical circuit as being either open or closed. At the end of the day, no matter how complex a computer or computer program seems, it is simply manipulating 0s and 1s. This does not allow for any uncertainty, with there only being two definite states (open or closed) known as bits. A quantum computer is not restricted to definite states. Quantum computers leverage something known as quantum bits (qubits). Without going into details as to how this is achieved, it basically introduces a state known as superposition, which means that it can be in two states at the same time. Let’s use a flipping coin as an example; a traditional computer would allow for the two end states (heads or tails) while a quantum computer could also work with the uncertain state, namely the flipping part before it becomes heads or tails (as well as the probability of each outcome). These probabilities can also be raised or lowered by doing certain operations. While this might not seem all that beneficial at first, combining this aspect with another called entanglement* allows for some pretty unbelievable things.

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The classic maze. A traditional computer would have to try every single path one after the other, while a quantum computer would be able to make use of superposition (during the search it can enhance the probability of ending on the right answer) and entanglement to arrive at the correct path much faster. Of course, this is a drastically simplified explanation, but it sufficiently highlights the benefits of a quantum computer. These benefits would be further accentuated, as the problems get even more complicated. But this is only one of the advantages: being able to solve certain problems faster than a classical computer. However, there are also tasks that only a quantum computer can carry out. Among these are tasks like simulating certain chemical reactions or other experiments that rely on quantum systems and can therefore only be reliably and efficiently simulated on a quantum computer.

Development

With all of the advancements in science which a quantum computer would provide, it isn’t hard to see why a lot of companies and organizations are working on it. Companies like Google and IBM have made massive breakthroughs in the quest for a functional and powerful quantum computer, but there are still many problems that need to be solved. Completely new algorithms will have to be written in order to run these computers, a daunting challenge for computer scientists. This is mostly due to the fact that the operations that are run in a quantum computer bear no resemblance at all to the algorithms and mathematics of today. Moving on to a more hardware level, current concepts for quantum computers require extremely low temperatures as well as an extremely isolated environment, because the quantum systems necessary for the running computer are very sensitive to any disturbances. Overcoming these challenges only grows to be larger and larger of a problem. The more qubits we add, the more complicated our computer becomes (but obviously this is necessary to increase the power of the computer).

Conclusion

A quantum computer would bring about a massive surge forward, not only in science but also in other fields like artificial intelligence (specifically machine learning) and cryptography. But due to the many technical difficulties still present, a truly ideal quantum computer is still a faraway dream. It is one that we can hold on to, though.

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*Entanglement allows for quantum objects to be linked, so that any changes made to one will instantly be made to the other, even over huge distances