Quantum computers: The world's first buyers' guide

Is there anything more to quantum computers than talk, talk, talk? You might have given up waiting – after all, it's been more than 30 years since physicist Richard Feynman came up with the idea. He wanted to harness spooky quantum effects to seriously surpass the processing power of any normal computer. In that time, normal computers have become around a billion times faster. Quantum computers, by contrast, are still struggling with primary school arithmetic.

At long last, though, there's good news. In laboratories around the world, researchers have been beavering away, and they can't help feeling there's magic in the air. "Some aspects of this field are getting tantalisingly close," says Matthias Steffen of IBM's quantum computing division based in New York. You can even buy a quantum computer right now – maybe – but you'll need deep pockets. It doesn't matter what apps you're planning to run, this much computational horsepower doesn't come cheap.

With that warning in place, let New Scientist help you make an informed choice – whether you're an online game freak looking to take multiplayer to a whole new level, an engineering powerhouse looking to stay one step ahead, or a security service worried about keeping the nation's secrets under lock and key. Over the next few pages you'll find out what they can do, what different kinds are on offer, and whether you'll have to turn the back bedroom into a cryogenic coolant plant.