What's stopping us from building useful quantum computers? And how long until we'll have them?

Quantum computers often grab the science headlines. But what exactly is quantum computing? What will quantum computers be able to do, and when can we expect to have fully functional ones?

An untapped resource could provide the magic needed for quantum computation — and perhaps even open the door to time travel.

Here's a brief introduction to the possible future of computing.

Why it's hard to build quantum computers and what can be done about it.

The 2012 Nobel Prize for Physics has been awarded to Serge Haroche and David J. Wineland for ground-breaking work in quantum optics. By probing the world at the smallest scales they've shed light on some of the biggest mysteries of physics and paved the way for quantum computers and super accurate clocks.

When it comes to the science of the very small, strange things start happening, and our intuition ceases to be a useful guide. Plus finds out about the crazy quantum world, and spin that a politician would die for.