A classical computer processes information in the form of bits. Any given bit, at any given time, can exist in either of two states: a one or a zero.
A quantum computer, however, processes “qubits”. Any given qubit, at any given time, can be a one, a zero, or it can be in “superposition”: neither of those states.
When a qubit is in superposition, it’s like a flipped coin spinning in midair. (No, you’re right – it’s not like that. But trust us, unless you’ve time to dive much deeper, the analogy’s helpful.) There’s some probability the qubit/coin will land on one/heads, and some probability it’ll land on zero/tails.
Now, imagine a labyrinth with one entrance and one exit. To find the quickest path through, a classical computer would have to explore each in turn by making a choice – heads or tails, one or zero – every time the path divides.
You can think of a quantum computer as placing a spinning qubit/coin at every junction of the maze. While the qubits are in this state, they can be carefully manipulated to increase the likelihood that, when they’re measured – when the coins land – the correct path is revealed.
Suffice to say, this opens some powerful computational doors. Questions that a classical supercomputer would need trillions years to chew over could, in theory, be answered by a quantum computer in a matter of days.
(If you do want to plunge deep into the technology’s fundamental principles, check out our quantum computing bookshelf at the end of this guide.)