Alain Aspect, John Clauser, and Anton Zeilinger, physicists, laid the groundwork for quantum technology.
The 2022 Nobel Prize in Physics has been awarded to tests of quantum weirdness and its potential real-world applications.
We are all subject to quantum rules at some level, which Albert Einstein struggled to understand. These rules are mostly observed behind the scenes in transistors that comprise computer chips, lasers, and even the chemistry of atoms and molecules in materials all around us.
Applications resulting from this year's Nobel Prize make use of quantum properties at larger scales. They include completely secure communications and quantum computers, which may one day solve problems that no conventional computer could ever solve in the entire history of the universe.
The prize this year is shared by three physicists. Alain Aspect and John Clauser confirmed that quantum mechanics rules the world, as strange and difficult to believe as they are, while Anton Zeilinger has used strange quantum behavior to develop rudimentary applications that no conventional technology can match. Each laureate will receive one-third of the prize money, which totals ten million Swedish kronor ($915,000 as of October 4).
"Today, we honor three physicists whose pioneering experiments demonstrated that the strange world of entanglement... is not just the micro-world of atoms, and certainly not the virtual world of science fiction or mysticism, but it's the real world that we all live in," said Thors Hans Hansson, a member of the Nobel Committee for Physics, at the Royal Swedish Academy of Sciences press conference announcing the award on October 4 (SN: 11/5/10).
"Learning about the three laureates was certainly very exciting," says physicist Jerry Chow of IBM Quantum in Yorktown Heights, N.Y. "Aspect, Zeilinger, and Clauser are all very well known in our quantum community, and their work has been an important part of many people's research efforts over many years."
Aspect, of the Université Paris-Saclay and École Polytechnique in France, and Clauser, who now runs a company in California, demonstrated that there are no hidden back channels of communication that explain how two particles can exist as a single entity despite being separated by a large distance (SN: 12/29/14).
Zeilinger's experiments at the University of Vienna rely on quantum behavior to demonstrate communications, absolutely secure encryption, and components critical for quantum computers. Another widely misunderstood application he pioneered was quantum teleportation. In contrast to science fiction's teleportation of people and objects, the effect involves the perfect transmission of information about a quantum object from one location to another.
"I was always interested in quantum mechanics from the first time I read about it," Zeilinger said over the phone at the award ceremony. "Some of the theoretical predictions actually struck me because they did not fit the usual intuitions that one might have."
The discovery of quantum behavior, which governs the world on small scales, such as electron motion around an atom, revolutionized physics at the turn of the twentieth century. Many prominent scientists, most notably Einstein, acknowledged that quantum theories worked but argued that they couldn't be the true description of the world because they only involved calculating the probabilities that something would happen (SN: 1/12/22). This meant to Einstein that there was some hidden information that experiments were unable to uncover.
Others believed that, while quantum behavior, also known as weirdness, was difficult to understand, it had no hidden methods of transmitting information. Until physicist John Bell proposed a test in the 1960s to prove that there were no hidden channels of communication among quantum objects, it was largely a matter of opinion and debate (SN: 12/29/14). At the time, it was unclear whether or not an experiment to perform the test was feasible.
|John Clauser devised the first practical experiment to confirm Bell's test, which demonstrated that there are no hidden channels of communication between quantum objects. GRAPHIC ARTS UNIVERSITY OF CALIFORNIA/LAWRENCE BERKELEY LABORATORY|
Clauser was the first to devise a practical experiment to confirm Bell's test, though there were some gaps in his experiment that left room for doubt. (His interest in science began at a young age. Clauser competed in the National Science Fair, now known as the International Science and Engineering Fair, in 1959 and 1960 (SN: 5/23/59). The Society for Science, which publishes Science News, organizes the fair.
Aspect expanded on the idea to eliminate any possibility that quantum mechanics had hidden underpinnings in classical physics (SN: 1/11/86). Clauser and Aspect's experiments involved creating entangled pairs of photons, which were essentially a single object. The photons remained entangled even as they moved in different directions. That is, they persist as a single, extended object. Measuring one's characteristics reveals characteristics of the other, no matter how far apart they are.
Entanglement is a delicate situation that is difficult to maintain, but the results of Clauser and Aspect's experiments show that quantum effects cannot be explained by any hidden variables that would indicate non-quantum underpinnings.
According to Chow, the significance of this study is twofold. "From a philosophical standpoint, there's really an element of demonstrating that quantum mechanics is real," he says. "However, from a more practical perspective... this same beautiful theory of quantum mechanics provides a different set of rules by which information is processed." As a result, next-generation technologies such as quantum computers and communications have new avenues to explore (SN: 12/3/20).
Zeilinger's experiments use entanglement to accomplish feats that would be impossible without the effects confirmed by Clauser and Aspect. He has extended the experiments from the lab to intercontinental distances, raising the prospect of entanglement being used in practical applications (SN: 5/31/12). Because interacting with one of a pair of entangled particles affects the other, they have the potential to be important components in secure communications and encryption. An outsider attempting to listen in on a quantum communication would be revealed because their snooping would break the entanglement.
Quantum computers based on entangled particles are also a hot topic of research. Instead of the ones and zeros of traditional computers, quantum computers encode information and perform calculations using a combination of the two. They can, in theory, perform calculations that no digital computer could ever match. Zeilinger's quantum teleportation experiments provide a method for transferring the information required by quantum computers (SN: 1/17/98).
"This [award] is a very nice and positive surprise for me," says Nicolas Gisin, a physicist at Switzerland's University of Geneva. "This award is well-deserved, but it comes a little late." The majority of that work was completed in the [1970s and 1980s], but the Nobel Committee was slow to respond and is now rushing to capitalize on the boom in quantum technologies."
According to Gisin, this boom is occurring on a global scale. "Billions — literally billions — of dollars are poured into this field in the United States, Europe, and China." So everything is changing," he says. "Instead of a few individuals pioneering the field, we now have huge crowds of physicists and engineers working together."
Although some of the most esoteric quantum applications are still in their infancy, Clauser, Aspect, and Zeilinger's experiments bring quantum mechanics and its strange implications to the macroscopic world. Their contributions validate some of quantum mechanics' key, once-controversial ideas and promise novel applications that may one day be commonplace in everyday life, in ways that even Einstein couldn't deny.
Nobelprize.org. The Nobel Prize in Physics will be awarded in 2022. Online since October 4, 2022.