Nobel Physics Prize Awarded for Pioneering A.I. Research by 2 Scientists

With work on machine learning that uses artificial neural networks, John J. Hopfield and Geoffrey E. Hinton “showed a completely new way for us to use computers,” the committee said.

John J. Hopfield and Geoffrey E. Hinton were awarded the Nobel Prize in Physics on Tuesday for discoveries that helped computers learn more in the way the human brain does, providing the building blocks for developments in artificial intelligence.

The award is an acknowledgment of A.I.’s growing significance in the way people live and work. With its ability to make sense of vast amounts of data, machine learning that uses artificial neural networks already has a major role in scientific research, the Nobel committee said, including in physics, where it is used for the creation of “new materials with specific properties.”

The breakthroughs of Dr. Hopfield and Dr. Hinton “stand on the foundations of physical science,” the committee said on X. “They have showed a completely new way for us to use computers to aid and to guide us to tackle many of the challenges our society face.”

Journalists attending the announcement in Stockholm took turns asking Dr. Hinton, who has been called the “godfather of A.I.,” questions about his work, and he expressed worries over machine learning and said it would have an extraordinary influence on society.

“It will be comparable with the Industrial Revolution,” he said. “Instead of exceeding people in physical strength, it’s going to exceed people in intellectual ability. We have no experience of what it’s like to have things smarter than us.”

While Dr. Hinton expressed his concerns, he shared that the advanced technology would bring much better health care. “It’ll mean huge improvements in productivity,” he said. “But we also have to worry about a number of possible bad consequences, particularly the threat of these things getting out of control.”

Who are the winners?

Dr. Hinton, born just outside London, has mostly lived and worked in the United States and Canada since the late 1970s. He recently retired from his job as a researcher and vice president at Google — in part, he said, so that he could speak freely about the rise of A.I. — and is a professor of computer science at the University of Toronto.

Dr. Hinton began researching neural networks as a graduate student at the University of Edinburgh in the early 1970s, a time when few researchers believed in the idea. Forty years later, Dr. Hinton doubled down on the concept, starting a new effort with the help of other researchers to tackle the technology with backing from the Canadian government.

After Dr. Hinton and two of his graduate students made a breakthrough with the technology in 2012, he joined Google. In 2019 — together with Yoshua Bengio, a professor of computer science at the University of Montreal whose research focuses on ensuring that A.I. is developed safely, and Yann LeCun, the chief A.I. scientist at Meta — he received the Turing Award, often called the “Nobel Prize of computing,” for their work on neural networks.

John J. Hopfield, a Chicago native, is an emeritus professor at Princeton known for seminal discoveries in computer science, biology and physics.

Dr. Hopfield began his career at Bell Laboratories in 1958 as a physicist studying the properties of solid matter, but felt limited by the boundaries of his field. He moved to the University of California, Berkeley as an assistant professor in 1961 and joined the physics faculty at Princeton in 1964. Sixteen years later, he moved to the California Institute of Technology as a professor of chemistry and biology, and in 1997, returned to Princeton, this time in the department of molecular biology.

In the 1980s, his work focused on how the processes of the brain can inform how machines save and reproduce patterns. In 1982, Dr. Hopfield developed a model of neural networks to describe how the brain recalls memories, known today as the Hopfield network. This enabled the ability for machines to “store” memories using artificial neural networks.

Why did the committee say the scientists were receiving the prize?

Both laureates helped lay the foundation for machine learning, the committee said. Dr. Hopfield “created a structure that can store and reconstruct information,” it said, while Dr. Hinton “invented a method that can independently discover properties in data and which has become important for the large artificial neural networks now in use.”

Since it was first awarded in 1901, the Nobel Prize in Physics has honored research from the discovery of subatomic particles to gravitational waves and supermassive black holes. But in some years, the committee has acknowledged the application of physics to other disciplines, like in 2021 for work contributing to understanding of climate change.

For Tuesday’s award, the committee emphasized the way that Dr. Hopfield’s and Dr. Hinton’s work in computer science had roots in the physical sciences.

The artificial neural network devised by Dr. Hopfield enables machines to store “memories” that can be “recalled” when fed partial information, similar to the method your brain uses to remember a word on the tip of your tongue. This ability is called associative memory. In describing the nodes and their linkages in the Hopfield network, Dr. Hopfield’s work showed that their behavior resembled the physics that explains how nearby atoms in a magnetic material influence each other’s spin.

Dr. Hinton and his colleagues built upon this foundation to develop a new neural network in 1985.

As with Dr. Hopfield’s research, the nodes in Dr. Hinton’s network could be described with physics. But instead of spin, they used the Boltzmann equation, named for the statistical physics pioneer Ludwig Boltzmann. The equation describes the energy of a system. They named it the Boltzmann machine, and it was one of the first examples of generative A.I., a model that improves by training on existing data, like ChatGPT.

In the decades that followed, Dr. Hinton and his colleagues explored other forms of neural networks that eventually gave rise to a wide range of technologies, including speech-recognition systems, language translation applications and chatbots.

What did the laureates say about winning the prize?

Dr. Hinton told the committee by telephone on Tuesday that he was “flabbergasted” by the news of receiving the award. “I had no idea this would happen.”

Dr. Hinton, who said he was speaking from a “cheap hotel” in California, said the news had come like a bolt from the blue. “I was going to get an M.R.I. scan today, but I think I’ll have to cancel that.”

Who received the 2023 Nobel Prize in Physics?

The prize was shared by Pierre Agostini, Ferenc Krausz and Anne L’Huillier for work that let scientists capture the motions of subatomic particles moving at impossible speeds.

Who else has received a Nobel Prize in the sciences this year?

On Monday, the prize in Physiology or Medicine went to Victor Ambros and Gary Ruvkun for their discovery of microRNA, which helps determine how cells develop and function.

When will the other Nobel Prizes be announced?

• The Nobel Prize in Chemistry will be awarded on Wednesday by the Royal Swedish Academy of Sciences in Stockholm. Last year, the prize went to Moungi G. Bawendi, Louis E. Brus and Alexei I. Ekimov for discovering and developing quantum dots that are expected to lead to advances in electronics, solar cells and encrypted quantum information.
• The Nobel Prize in Literature will be awarded on Thursday by the Swedish Academy in Stockholm. Last year, Jon Fosse of Norway was honored for plays and prose that gave “voice to the unsayable.”
• The Nobel Peace Prize will be awarded on Friday by the Norwegian Nobel Institute in Oslo. Last year, Narges Mohammadi, an activist in Iran, was recognized “for her fight against the oppression of women in Iran and her fight to promote human rights and freedom for all.” Ms. Mohammadi is serving a 10-year sentence in an Iranian prison where her attorneys have raised concerns about her well-being.
• Next week, the Nobel Memorial Prize in Economic Sciences will be awarded on Monday by the Royal Swedish Academy of Sciences in Stockholm. Last year, Claudia Goldin was awarded for her research uncovering the reasons for gender gaps in labor force participation and earnings.

All of the prize announcements are streamed live by the Nobel Prize organization.

Adam Satariano contributed reporting.