It may not be long until they overtake our fastest supercomputersby Philip Ball / May 5, 2016 / Leave a comment
I’d expected to have to wait a decade or so before I could use a quantum computer. But on the contrary I can do it today. And so can you. From 4th May, technology multinational IBM is making its prototype quantum processor available for the public to use on a cloud-based platform accessible from any mobile or desktop device.
In the IBM Quantum Experience you can run experiments and algorithms that use “quantum bits” (qubits). Roughly speaking, these are like the transistor-based bits of regular computer circuits that process information as binary 1’s and 0’s, but manipulated according to the laws of quantum mechanics.
These laws make qubits immensely more versatile than the classical bits of your laptop. At any moment they can be not just in two possible states—a 1 or a 0—but in so-called superpositions of those states, such as “half 1 and half 0,” or any other combination of the two. This means that qubits have access to a much bigger range of states, and that variety allows them to perform certain tasks much more rapidly than classical bits. This is often expressed in terms of quantum computers performing many calculations in parallel whereas classical computers can only do one at a time—an over-simplification of where “quantum speedup” comes from, but adequate to give an impressionistic view of what is special about quantum computers. (When Canadian prime minister Justin Trudeau wowed the press last month with an impromptu explanation of quantum computing, he did well to keep it a bit vague.