By Don Lincoln on October 11, 2012 11:44 AM |
Quantum mechanics is one of the most devilishly confusing theories ever devised. Cats that are simultaneously alive and dead, objects that are both particles and waves, subatomic particles that know whether you are looking at them or not—and, most bafflingly, these quantum effects can be erased when individual atoms, electrons, and photons interact with their environment.
That is what makes Serge Haroche and David Wineland’s Nobel Prize-winning work in physics so remarkable: They have achieved mastery of the microrealm. Both of them have spent decades trying to generate systems in which a single atom or a single photon can be studied.
David Wineland, at the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder, is an expert at trapping individual atoms using electric fields and by keeping them in an ultra-high vacuum. The mastery of individual atoms is possible by artfully employing laser beams and laser pulses. The laser beams can cool the motion of the atoms and even can transfer quantum information about the atom’s location to the location of electrons inside the atom. This is an extraordinary achievement.
Serge Haroche, of the Collége de France and the Ecole Normale Supérieure, Paris, essentially does the opposite. He uses atoms to study individual photons. Using superconducting niobium, he creates the two most reflective mirrors ever achieved. With the mirrors placed about an inch apart, he introduces a single photon, which bounces back and forth for over a tenth of a second until it eventually hits an imperfection in the mirror and is absorbed. While the photon is bouncing, it travels a distance equivalent to circling the entire globe.
In order to measure the photon, Haroche fires single rubidium atoms through his equipment. These atoms are of a special class called “Rydberg atoms,” in which the electrons “orbit” very far from the atomic nucleus. (Though we now know that atoms do not operate as mini solar systems, the analogy of orbits can still be a useful one.) By measuring the configuration of the Rydberg atom before and after it travels through his apparatus, Haroche can determine if there is a photon inside his equipment without absorbing or altering the photon.
These techniques have made it possible to probe quantum mechanics in more detail than ever before, with Haroche’s work making it possible to effectively make a movie of the transition of a photon from one state to another, a process that scientists call “the collapse of the wave function." But these two scientists’ work has more practical applications. For instance, if we are able to put equipment into a quantum state and read that state without destroying it, this opens the possibility of quantum computing. The potential power of quantum computing is enormous and if we are able to actually accomplish it, this will change computing in the same degree that ordinary computing has changed the world since the 1940s. Quantum computing is still a ways in the future, but Haroche and Wineland’s work has brought it closer to fruition.
Wineland's work has also made possible a new generation of clocks that are 100 times more accurate than the best timekeepers in the world. These new clocks are precise to one part in 1017. To give some context, if these clocks were started when the universe began 13.7 billion years ago, by now they would be off by a mere four seconds. Such accuracy is useful for communication and navigation, and could also enable even more stringent tests of Einstein’s theory of general relativity, which states that time runs slower in stronger gravitational fields. When people think about this effect, they usually invoke the mind-bending gravitational fields surrounding black holes, but these new clocks are so precise that the effect of time dilation due to gravity would be obvious if one of them were raised a mere foot off the surface of the Earth.
Haroche and Wineland’s work is of the highest caliber, with potential society-changing implications. In this year’s Nobel Ceremony on December 10, they will rightfully join their peers in the pantheon of great scientists.
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Explore Haroche and Wineland's Nobel Prize-winning work in this technical-level article.
By Charles Choi on August 28, 2012 2:13 PM |
The Nobel Prize may be the most prestigious award in science, but the new Fundamental Physics Prize is by far the world's most lucrative scientific award, instantly making its first winners this August multimillionaires. But the size of the payout isn’t the only difference between the two prizes: Unlike the Nobel, the Fundamental Physics Prize can be awarded for research that has not yet been verified by experiment. Is it foolhardy to extol work later findings might prove wrong?
The Fundamental Physics Prize is the brainchild of Russian tycoon Yuri Milner, a one-time physics graduate student turned billionaire investor in internet companies such as Facebook, Twitter, Groupon and Zynga. Milner personally selected the inaugural class of nine winners, each of whom received $3 million, roughly three times as much as a Nobel grant.
Although some of the work recognized by this year’s awards has been experimentally verified (for example, the principles of quantum computers are firmly grounded in experiment), others, like string theory, which compares elementary particles to loops of vibrating string, and the holographic principle, which suggests that our three-dimensional reality is a projection of information stored on a far-off two-dimensional surface, live further out on a theoretical limb.
Ideas like these may not get experimental verification any time soon, either. Take string theory. As Fundamental Physics Prize winner Ashoke Sen, a string theorist at the Harish-Chandra Research Institute in India, explains, "Unfortunately the strings are so small that the energy required for seeing these structures is huge, much larger that what we have achieved in the present day accelerators.”
Yet many physicists (including, unsurprisingly, some Milner honorees) argue that unverified ideas, and even ideas that are unverifiable with today’s technology, are prizeworthy—even if future tests should prove them wrong.
"Many of the most important developments in physics involve subjects for which there is little hope of experimental verification anytime soon," argued cosmologist Alan Guth at the Massachusetts Institute of Technology, one of the winners of the Milner prize. Guth invented the theory of cosmological inflation, which suggests our universe expanded staggeringly just a sliver of a second after it was born. This rapid expansion that would help explain, among other things, why the cosmos is so extraordinarily uniform on large scales, with only very tiny variations in the distribution of matter and energy.
In fact, two of the greatest theoretical breakthroughs of the 20th century—Albert Einstein's theories of special and general relativity—were never honored by a Nobel Prize, said Stanford cosmologist Andrei Linde, another winner of the Fundamental Physics Prize. These ideas changed the world by showing that mass and energy are equivalent and that gravity is a result of mass curving the fabric of space and time. Although Einstein was awarded the Nobel Prize in 1921, he was given the prize not for relativity but for describing how light was composed of discrete packets of energy now called photons, because the Nobel committee felt that relativity had not at the time been verified.
"More recently, we have the case of the Higgs particle, with almost 50 years between the theoretical advance and the experimental verification," Guth added. "If this kind of theoretical work is not respected, then progress in fundamental physics would suffer tremendously."
Even if theoretical research does lead to a dead end, it can help inform what ultimately prove to be successful ideas, said theoretical physicist Nima Arkani-Hamed at the Institute for Advanced Study in Princeton, New Jersey, a winner of the new prize who has investigated ideas such as extra dimensions of reality and new theories regarding the Higgs particle.
"One of the great developments in physics in the 20th century was the Standard Model of particle physics, which explains particles such as electrons and quarks and gluons," Arkani-Hamed said. "But before the Standard Model was known to work, there were people exploring lots of other theoretical possibilities that might be consistent with our world. Even if they didn't pan out, collecting ideas that have a chance of working may help lead to developments like the Standard Model."
“Wrong” ideas can advance science in other ways, too. "We should keep in mind that Newtonian mechanics was ultimately found to be incorrect, but it nonetheless was a momentous force in driving science forward," Guth said. "Today there are many developments in physics that are recognized by the community as being important, even though we cannot prove that they are correct."
As to how the prize-winners might spend their gains, other than paying taxes and mortgages, they often said they were still in shock over the award. "I continue to remind my students that they should not go into physics for the money," Guth said.
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By Kate Becker on March 29, 2012 10:21 AM |
Physicists are on the brink of a breakthrough discovery: They may have finally cornered the Higgs boson, the subatomic particle hypothesized to give mass to all the stuff in the universe. But should we really be calling this particle the “Higgs”?
A computer simulation of a detection of the Higgs boson. Or is that the ABEGHHK’tH boson? Credit: David Parker/Photo Researchers, Inc.
Peter Higgs, it turns out, wasn’t the only one to come up with the idea of a new field (the Higgs field) that endows particles with mass. In fact, he wasn’t even the first to publish the theory. That distinction goes to Robert Brout and Francois Englert at the Free University in Brussels, who wrote up the idea in August 1964. Higgs was close on their heels with his own paper in October of the same year. Just a few weeks later, Dick Hagen, Gerald Guralnik, and Tom Kibble published their take on what would come to be known as the Higgs field and Higgs boson.
This wasn’t plagiarism: It was a kind of synchronicity that is the norm in science, says MIT science historian David Kaiser. In fact, independent research groups simultaneously arrive at similar breakthroughs so often that Robert Merton, a sociologist of science, put a name to the phenomenon: multiples. One famous multiple is calculus, which was simultaneously “discovered” by both Isaac Newton and Gottfried Leibniz in the late 17th century. More recently, the accelerating expansion of the universe was observed at nearly the same time by two competing groups of astronomers, both of which were honored with the Nobel Prize in physics in 2011.
Higgs, Brout, Englert and the rest were continuing a tradition that is as old as physics itself. But why is “Higgs” the name that stuck? “Higgs expressed the challenge”—how do we get particles that have mass and still obey the rules of symmetry?—“and the expected solution especially sharply,” says Kaiser. Another recounting pins the name on Ben Lee, a physicist who used “Higgs” as shorthand in a 1972 Fermilab conference program after having had a productive lunch chat with Higgs.
Higgs himself has always been uncomfortable seeing his name ride solo. He prefers to call the particle the “scalar boson” or the “so-called Higgs,” Ian Sample writes in his book “Massive.” Higgs has also advanced the uncommonly inclusive acronym ABEGHHK’tH—that’s the Anderson, Brout, Englert, Guralnik, Hagen, Higgs, Kibble and ‘t Hooft—to honor all the scientists who played a part in originating the theory.
Frank Wilczek, a Nobel prize-winning physicist who has named a few particles of his own (anyons and axions—the latter inspired by a laundry detergent), thinks that the alphabet soup solution would be “especially absurd.” Says Wilczek: “History is complicated, and wherever you draw the line there will be somebody just below it!”
If the Higgs discovery is confirmed, though, someone will have to draw that line—and that someone will be the Nobel Prize committee. The discovery is seen as a shoo-in for the physics honor, but the prize can be divided among no more than three laureates. There are at least six scientists with reasonable claims on the Higgs—not to mention the cast-of-thousands teams whose instruments are responsible for the experimental evidence that the Higgs actually exists.
Complicating matters is physicists’ anarchic naming methodology. When astronomers have planets, moons, and asteroids in need of naming, they turn to the International Astronomical Union. Elements get their formal names from the International Union of Pure and Applied Chemistry. Physicists, who have no such official naming body, have historically opted for descriptive names, like “neutrino” (“little neutral one”), or names devoid of any physical meaning at all, like “up,” “down,” and “charm.” As a particle named after a person, the Higgs is essentially alone among the fundamental elementary particles.
So what should we be calling the Higgs? “By now it's so deeply embedded in the literature that changing to another name would be jarring, and might introduce a gratuitous complication in literature searches or eventually even a hurdle to parsing older papers,” says Wilczek. If he had to choose? “A possibly better choice might be ‘zeron,’ to connote that the particle has zero quantum numbers, and in some sense is an ingredient of what we call nothingness.”
“I’d find a fancy-sounding word in ancient Greek, to give it gravitas, and then add ‘on,’” says Kaiser. In the absence of a Greek dictionary, Kaiser nominates “lardon”—a particle that makes things heavy.
Ultimately, it may come down to branding. “In business, it would be considered destructive to take a well-known name and replace it with a long-winded, technical-sounding alternative that no one has heard of,” wrote the editors of Nature in a recent editorial. Indeed, “Higgs” seems to have captured the public imagination—and it makes a much better Twitter hashtag than #ABEGHHK’tH.
Now it’s your turn: If you could rename the Higgs, what would you call it?
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