Philip Anderson, legendary theorist whose ideas shaped modern physics, dies | Science
Philip Anderson, the theoretical physicist whose ideas reshaped condensed matter physics and stretched to the forefront of different fields, died yesterday in Princeton, New Jersey. He was 96. Anderson had spent the previous 45 years at Princeton University, which confirmed his demise in an announcement.
Feisty and cantankerous, Anderson made contributions that rival these of famed American theorist Richard Feynman, who died in 1988, says Michael Norman, a theorist at Argonne National Laboratory: “Phil was a true giant of physics, one of the greatest ever.”
Anderson established himself within the 1950s by displaying how dysfunction within the association of atoms in a crystal may lure in any other case free-flowing electrons in a particular spot, a quantum impact referred to as Anderson localization, for which he shared the 1977 Nobel Prize in Physics. The phenomenon is far deeper than it could sound, because it requires the quantum wave of the electron to overlap and intervene with itself to maintain it from spreading.
Around the identical time, Anderson deciphered supplies referred to as antiferromagnets, that are a bizarre riff on extra widespread magnetic supplies referred to as ferromagnets. In a ferromagnet similar to iron, all of the atoms act like little magnets and so they all level in the identical route to magnetize the complete materials. In an antiferromagnet, similar to chromium, neighboring atoms level in reverse instructions to type an up-down-up-down sample.
At the time, that sample vexed physicists. That was as a result of, on very normal quantum ideas, they may consider no interplay among the many magnetic atoms that may have the suitable symmetry to provide that sample. However, Anderson employed an idea name spontaneous symmetry breaking to argue that time was irrelevant. He confirmed materials may have a lowest vitality floor state that featured the sample even when the interactions didn’t explicitly encode it. In essence, the symmetry of the interplay is damaged by the bottom state.
In the early 1960s, Anderson used the idea of spontaneous symmetry breaking to elucidate why a superconductor—a fabric that may carry electrical energy with out resistance if cooled sufficiently near absolute zero—expels a magnetic subject. In doing so, he confirmed photon would change into large inside a superconductor. Just 1 yr later, British theorist Peter Higgs fleshed out that concept in a little bit of idea that in the end has change into particle theorists’ clarification of how all basic particles get their mass from interactions with the vacuum. (Yes, the speculation posits that the vacuum is in some very summary manner like the within of superconductor.) Thus, Anderson got here inside just some steps of inventing the Higgs mechanism and the particle that goes with it, the Higgs boson, says Piers Coleman, a theorist at Rutgers University, New Brunswick.
Later, Anderson claimed to have solved one other thriller: high-temperature superconductors. In the late 1980s experimenters found a category of complicated supplies that comprises copper and oxygen and may superconduct at temperatures far above these predicted by the traditional idea of superconductivity. Anderson rapidly proposed his personal idea, referred to as the resonating valence bond idea, which he claimed defined the phenomenon. However, others discovered the concept unconvincing—one outstanding theorist dubbed it “rather vague bullshit”—and the puzzle of high-temperature superconductivity stays unresolved to at the present time.
Although Anderson’s efforts stretched over many fields, they shared a typical conceptual basis, Coleman says. In the mid-1900s, many physicists employed an excessive reductionist strategy that assumed an issue was solved as soon as a system’s most basic constituent had been recognized and their interactions characterised, a tack exemplified in particle physics. In distinction, Anderson expounded the idea of emergence, which said that as any system grew bigger, new phenomena—similar to antiferromagnetism and superconductivity—may emerge that would not be predicted from the basic interactions. “You have to see him as having made these tremendous scientific contributions, but also having this philosophical point of view that was tremendously powerful,” Coleman says.
Over his lengthy profession, Anderson earned a status for being combative and, at instances, making scientific disputes private. “He was not afraid of a fight, even when he was wrong,” Norman says. That strategy possible grew out of Anderson’s years on the famed Bell Labs, the place Anderson labored from 1949 to 1984 and the place a tradition of brutal honesty and combativeness reigned. Norman remembers a very sharp barb Anderson threw one night. “We went to dinner and somebody made the mistake of asking Phil what he thought of his theory,” Norman says. “Phil just looked at him and said, ‘Not much.’”
But Anderson was additionally variety to his college students and collaborators, says Coleman, who was Anderson’s graduate pupil from 1980–84. “He was extremely sweet with his students and pushed very hard for them.”