Quantum computers have been talked about for years, but it is only recently that they have come into existence. But what is a quantum computer? A quantum computer simply makes use of quantum mechanics to perform operations. To go any further into explaining quantum computers would mean to enter the world of superposition, entanglement and qubits.
Instead, let us look at what they can do for us, and when we can use them.
A quantum computer has a qubit at its heart, instead of a transistor, and gives a quantum computer the capability to compare data not only at a fast rate, but simultaneously. For example, if you have a book with 1 million names and phone numbers, sorted by name, and you needed to match a phone number. A normal computer would have to look at each phone number and perform a compare operation on each number, so it would take 1 million steps. A quantum computer could do the same action in 1,000 steps.
Another example is in performing calculations. Using another quirk of quantum computers makes it possible to perform billions of versions of a calculation at the same time. This is wonderful news for chemistry, biology and medicine which are suited for the type of calculations a quantum computer can perform. Another specialty for quantum computers is breaking current encryption systems, although steps are being taken to ensure that the latest encryption systems cannot be cracked even by a quantum computer.
One more example of quantum computers is in communications. China recently achieved a record for “spooky action at a distance” by having intertwined quantum particles communicate from a satellite to ground stations, separated by 1200 kilometers. Or in layman’s terms, “linked” particles copying each other while being separated by 1200 km, enabling a form of communication that is impossible to be hacked, as nothing is actually transmitted. This form of communication isn’t fast, so it is not viable for messages, but is great for securely sending encryption keys between two endpoints, which are relatively small, enabling hacker-proof encryption.
But the bad news is that a quantum computer still can’t solve problems like the famous Travelling Salesman Problem: Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the origin city?
The other bad news is that there are only a few quantum computers in the world. D-Wave sells one of the only proven quantum computers, although other companies are developing systems. Google has a 9-qubit computer and is in the finishing stages of a 49-qubit chip. Microsoft does have a quantum computer project, and they hope to create dependable tools that scientists without a quantum background can use to solve some of the world’s most difficult problems, although it will be a few years until you see a quantum computer in Azure.