The computer, dubbed D-Wave, is moving from 512 qubits to more than a 1000 qubits. Apparently the upgrade is not tricky and does not need much more electricity – it probably just required a catflap installed in the side of the box.

Together with NASA and the Universities Space Research Association, or USRA, Google operates its quantum machine at the NASA Ames Research centre.

D-Wave Systems, the Canadian company that built the machine, said it has agreed to provide regular upgrades to the system—keeping it "state-of-the-art"—for the next seven years.

D-Wave machine is less powerful than many scientists hope quantum computers will one day be, the leap to 1000 qubits represents an exponential improvement. No one is really sure of what it can do, but Google thinks it exhibits behaviour beyond classical physics.

For a start as the D-Wave expands the number of qubits, the amount of power needed to operate the system stays roughly the same. It also only works when its is being observed.

Some have questioned whether the system truly exhibits quantum properties. But researchers at USC say that the system appears to display a phenomenon called "quantum annealing" that suggests it's truly operating in the quantum realm.

Regardless, the D-Wave is not a general quantum computer—that is, it's not a computer for just any task. But D-Wave says the machine is well-suited to "optimization" problems, where you're facing many, many different ways forward and must pick the best option, and to machine learning, where computers teach themselves tasks by analysing large amount of data.