What is a quantum computer?

Every year, new computers are being developed that are faster and smarter than ever before. But if you really want to take things to the next level, you've got to go quantum. CrowdScience listener Atikah in Hungary likes the sound of a quantum computer but wants to know: what exactly is it, what can it do that a normal computer can't, and how soon can she get hold of one? The digital devices in our everyday lives - from laptop computers to smartphones - are all based on 0s and 1s: so-called ‘bits’. But quantum computers are based on ‘qubits’ - the quantum 0s and 1s that are altogether stranger, but also more powerful. With the help of quantum computing researcher Jessica Pointing and a spinning doughnut, presenter Alex Lathbridge learns how these ‘qubits’ allow computers to perform calculations millions of times faster than normal. While quantum computers do exist, it turns out they're not yet big enough or stable enough to be really useful. Alex visits Professor Winfried Hensinger and his prototype quantum computer at the University of Sussex to understand what they can do right now, and why it’s so incredibly difficult to scale them up. He hears from the engineers racing to overcome the obstacles and unlock the potential of these mega-powerful systems. But once the engineering problems are solved, what then? Professor Shohini Ghose opens our eyes to the exciting range of possible applications - from helping create new drugs, to making electric batteries much more efficient and maybe even helping farmers fertilise their crops for a fraction of the price. Contributors - Jessica Pointing, Professor Winfried Hensinger, Professor Shohini Ghose

Presenter - Alex Lathbridge

Producer - Ilan Goodman

Sound Design - Jon Nicholls [Image: Winfried Hensinger in his lab at the University of Sussex, Credit: Universal Quantum]