Quantum computing uses the movement of subatomic particles to process data in amounts that modern computers can’t handle. Mostly theoretical now, the technology is expected to be able to perform calculations that make today’s computers look akin to an abacus.
The computers we use today are known as classical computers. They’ve been a driving force in the world for decades — advancing everything from healthcare to how we shop. But there are certain problems that classical computers will simply never be able to solve. Consider the caffeine molecule in a cup of coffee. Surprisingly, it’s complex enough that no computer that exists or could be built would be capable of modelling caffeine and fully understanding its detailed structure and properties. This is the type of challenge quantum has the potential to tackle.
Rather than store information using bits represented by 0s or 1s as conventional digital computers do, quantum computers use quantum bits, or qubits, to encode information as 0s, 1s, or both at the same time. This superposition of states—along with the other quantum mechanical phenomena of entanglement and tunnelling—enables quantum computers to manipulate enormous combinations of states at once.
Because a quantum computer is probabilistic rather than deterministic, the computer returns many very good answers in a short amount of time—thousands of samples in one second. This provides not only the best solution found but also other very good alternatives from which to choose.
Quantum systems may untangle the complexity of molecular and chemical interactions leading to the discovery of new medicines and materials. They may enable ultra-efficient logistics and supply chains, such as optimizing fleet operations for deliveries during the holiday season. They may help us find new ways to model financial data and isolate key global risk factors to make better investments. And they may make facets of artificial intelligence such as machine learning much more powerful.
Google, IBM and a handful of start-ups are racing to create the next generation of supercomputers, quantum computers.