American physicist Yoichiro Nambu, one of three winners of the 2008 Nobel Prize for Physics awarded on Tuesday, revolutionised scientific thinking about the nature of subatomic particles and how they move.

After more than a half-century at the forefront of his field, Nambu (87) won one half of the prestigious prize for work dating back to the 1960s on the groundbreaking mechanism of "spontaneous broken symmetry" in subatomic physics, the Nobel committee said.

Nambu shares the Nobel award with Japanese physicists Makoto Kobayashi and Toshihide Maskawa who expanded upon his theories to explain why the symmetries were broken.

Nambu's research forever changed scientists' understanding of how particles move and illuminated a range of phonenoma, including "the very origin of the cosmos in the Big Bang some 14 billion years ago," according to the Nobel citation.

And his theories formed an essential cornerstone of the Standard Model of elementary particle physics which explains and predicts how three of the four fundamental forces of nature interact.

Along the way, he has earned the deepest respect of his peers.

Edward Witten, a colleague at the Institute for Advanced Study in Princeton, New Jersey, said of Nambu in a 1995 Scientific American Magazine article: "People don't understand him, because he is so farsighted."

Another fellow physicist, Bruno Zumino of the University of California at Berkeley, confessed in the same article that at the beginning of their acquaintance, he sometimes struggled to comprehend Nambu's groundbreaking work.

"I had the idea that if I can find out what Nambu is thinking about now, I'll be 10 years ahead in the game," Zumino was quoted as saying.

"So I talked to him for a long time. But by the time I figured out what he said, 10 years had passed."

The recognition is long overdue, said colleague and fellow Nobel laureate James Cronin who described Nambu as an "extraordinarily modest man."

"These basic ideas — the dynamical symmetry breaking — was really the foundation of beginning to understand the model that works so beautifully in particle physics," said Cronin, who has worked with Nambu in the University of Chicago's physics department for more than 50 years.

"This probably wasn't understood or adapted very quickly — it's not like a eureka moment — but as his experimental data came it, and people came to understand how this all came together it was clear that these fundamental ideas were at the basis of making that understanding (possible.)"

Nambu said that while he retired from direct research about 17 years ago he has not stopped working and intends to maintain his position as an emeritus professor of physics at the University of Chicago's renowned Enrico Fermi Institute.

"I still try to work and think about the problems and try to understand them," he said. "I do want to do that until I die."

Born in 1921, Nambu received his doctoral degree from Tokyo University in 1952. That same year, he traveled to the United States to conduct research and stayed, eventually obtaining US citizenship in 1970.

His previous awards include the 1982 National Medal of Science — the highest US honor in the sciences. He also has received the Benjamin Franklin Medal in physics, the Wolf Prize in physics, the J. Robert Oppenheimer Prize and the Max Planck Medal. Nobel laureates receive a gold medal, a diploma and 10 million Swedish kronor ($1.42-million, €1.02-million) which can be split between up to three winners per prize.

The formal awarding of the prizes will take place in Stockholm on 10 December.

AFP