Quantum supremacy is coming. It won't change the world

If quantum computers are to help solve humanity's problems, they will have to improve drastically

The unveiling of the marvel had the media gushing. It was Valentine's Day 1946, and the New York Times broke the story. The front page spoke of "an amazing machine" and "one of the war's top secrets". By crunching numbers at unprecedented speed, the Electronic Numerical Integrator and Computer, with its 18,000 vacuum tubes, was poised to "revolutionise modern engineering". Eniac would usher in a new epoch of industrial design, some said.

More than 70 years on, another overblown announcement is near. Several companies, notably Google, IBM and the California-based Rigetti, are racing to build a machine that achieves what is grandly termed "quantum supremacy". The feat will mark the moment when a quantum computer, for the first time, outperforms the best conventional computers. Google, the frontrunner, could claim the record this year.