Google scientists say they've reached "quantum supremacy"

Google scientists said their quantum machine completed in less than 3.5 minutes a calculation that would take the most powerful present-day computers 10,000 years to finish.

How it works: Quantum machines use atomic particles to represent "qubits" — short for "quantum bit." One qubit can convey twice as much information as a single traditional computer bit, thus beefing up a system’s computing power. A system's computing power increases exponentially with each additional qubit.

Yes, but: IBM scientists, who are also developing quantum machines, recently argued that Google's team underestimated the power of current computers.

• IBM scientists claim that a modern computer system could perform the calculation in Google’s report in 2.5 days, and it would make fewer mistakes than Google's quantum machine.

Of note: There's debate over the utility of quantum random number generation — the task Google's machine completed. However, Google says it's important for next-generation cryptography.

Go deeper: Heading off the quantum encryption apocalypse