Serge Haroche (l) is based at the College de France and David Wineland is based at the US National Institute for Standards and Technology

BBC

This year's Nobel prize in physics has been awarded to two researchers for their work with light and matter at the most fundamental level.

Serge Haroche of France and David Wineland of the US will share the prize, worth 8m Swedish kronor (£750,000; $1.2m).

Their "quantum optics" work deals with single photons and ions, the basic units of light and matter.

It could lead to advanced modes of communication and computation.

The Nobel citation said the award was for "ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems".

Light and matter, when the minuscule scales of single particles are reached, behave in surprising ways in a part of physics known as quantum mechanics.

Working with light and matter on this level would have been unthinkable before the pair developed solutions to pick, manipulate and measure photons and ions individually, allowing an insight into a microscopic world that was once just the province of scientific theory.

Their work has implications for light-based clocks far more precise than the atomic clocks at the heart of the world's business systems, and quantum computing, which may - or may not - revolutionise desktop computing as we know it.

But for physicists, the import of the pair's techniques is that they preserve the delicate quantum mechanical states of the photons and ions - states that theorists had for decades hoped to measure in the laboratory, putting the ideas of quantum mechanics on a solid experimental footing.

Those include the slippery quantum mechanical ideas of "entanglement" - the seemingly ethereal connection between two distant particles that underpins much work on the "uncrackable codes" of quantum cryptography - and of "decoherence", in which the quantum nature of a particle slowly slips away through its interactions with other matter.

The prize is the second in quantum optics in recent years; the theory behind decoherence formed part of 2005's Nobel physics prize citation.

Prof Haroche was reached by phone from the press conference. He had been told he had won just 20 minutes before telling reporters: "I was lucky - I was in the street and passing near a bench, so I was able to sit down immediately.

"I was walking with my wife going back home and when I saw the... Swedish code, I realised it was real and it's, you know, really overwhelming."