The 2004 Nobel Prize in physics was awarded today to Americans David J. Gross, H. David Politzer, and Frank Wilczek for their work in the field of quarks. A quark refers to any of a group of subatomic particles carrying a fractional electric charge.
Gunnar Oquist, the secretary-general of the Royal Swedish Academy of Sciences, announced the winners in Stockholm.
"The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in physics for 2004 jointly to David Gross, David Politzer, Frank Wilczek, and I cite, 'for their discovery of asymptotic freedom in the theory for the strong interaction [between quarks],'" Oquist said.
In awarding this year's prize, the Nobel jury said Gross, Politzer, and Wilczek made an important theoretical discovery concerning the "strong force" -- or "color force" -- that is dominant in the atomic nucleus, acting between the quarks inside the proton and the neutron.
Lars Bergstrom is professor of theoretical physics at Stockholm University and secretary of the Nobel's committee for physics. He explains more about the "strong force."
"Here is gravity -- the force that we all know, that holds us on Earth. Then we have three other forces. The electromagnetic force that is responsible for all electric and magnetic phenomenon that everybody also uses nowadays. Then there is a weak force that has not so much to do with everyday life but that is very important, for instance, for the generation of energy of the sun. And then there is a strong force -- the force that bind quarks together three and three in protons and neutrons. And that is what this year's Nobel Prize is about -- how this strong force works," Bergstrom said.
What this year's laureates discovered, the jury says, was something that, at first sight, seemed completely contradictory -- the closer the quarks are to each other, the weaker is the "color charge." The converse is also true. Bergstrom says this property may be compared to a rubber band.
"Maybe one can, just as an example, take a rubber band like this. So if I stretch it, the force I need to elongate it becomes stronger and stronger. But then of course when I move my hands together at short distances, the force is very, very weak. Now for the strong force between the quarks in neutrons, everybody believed it would be the other way around," Bergstrom said.
The Nobel jury says that, thanks to their discovery, Gross, Politzer and Wilczek "have brought physics one step closer to fulfilling a grand dream -- to formulate a unified theory comprising gravity as well -- a theory for everything."
The first Nobel prize for physics was awarded in 1901 to Wilhelm Roentgen for his discovery of X-rays.
This year's award announcements began yesterday with the Nobel Prize in medicine going to Americans Richard Axel and Linda B. Buck for their work on the sense of smell.
The winner of the Nobel Prize in chemistry will be named tomorrow, followed by the literature prize on 7 October. The economics prize will be announced on 11 October.
The winner of the coveted Nobel Peace Prize -- the only one not awarded in Sweden -- will be announced Friday in Oslo, Norway.