Quantum computing is the use of quantum-mechanical phenomena such as superposition and entanglement to perform computation. A quantum computer is used to perform such computation, which can be implemented theoretically or physically.
The field of quantum computing is actually a sub-field of quantum information science, which includes quantum cryptography and quantum communication. Quantum Computing was started in the early 1980s when Richard Feynman and Yuri Manin expressed the idea that a quantum computer had the potential to simulate things that a classical computer could not. In 1994, Peter Shor shocked the world with an algorithm that had the potential to decrypt all secured communications.
What is quantum computing?
Quantum computing takes advantage of the strange ability of subatomic particles to exist in more than one state at any time. Due to the way the tiniest of particles behave, operations can be done much more quickly and use less energy than classical computers.
In classical computing, a bit is a single piece of information that can exist in two states – 1 or 0. Quantum computing uses quantum bits, or 'qubits' instead. These are quantum systems with two states. However, unlike a usual bit, they can store much more information than just 1 or 0, because they can exist in any superposition of these values.
Google, IBM and a handful of startups are racing to create the next generation of supercomputers. Quantum computers, if they ever get started, will help us solve problems, like modelling complex chemical processes, that our existing computers can't even scratch the surface of.
But the quantum future isn't going to come easily, and there's no knowing what it'll look like when it does arrive. At the moment, companies and researchers are using a handful of different approaches to try and build the most powerful computers the world has ever seen.