Scientists who conjured quantum phenomena at human scales awarded Nobel Prize in Physics

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Three scientists who demonstrated the surprising range of quantum effects in electrical circuits have been awarded the Nobel Prize in Physics.

On Tuesday, members of the Royal Swedish Academy of Sciences announced that this year’s physics Nobel will be shared by John Clarke of the University of California, Berkeley; John Martinis of the University of California, Santa Barbara; and Michel H. Devoret, also at the University of California, Santa Barbara, and Yale University.

The trio are being recognized for their discovery in the mid-1980s that a phenomenon known as quantum tunnelling – by which a subatomic particle can pass through a seemingly impenetrable barrier – can also occur at the scale of a macroscopic circuit.

For single-particles, the tunnelling effect already has a myriad of practical applications including the flash memory found in any cellphone. Work done by Tuesday’s prize winners shows how much further the phenomenon can extend. Their results have been fundamental to the development of quantum computers, which are projected to transform important aspects of the digital world in years to come.

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“We had not realized in any way that this might be the basis of a Nobel Prize,” said Dr. Clarke, when speaking with reporters in a telephone interview after the prize announcement.

He added that being informed that he was a Nobel laureate “was the surprise of my life.”

The award, bestowed each December at a special ceremony in Stockholm, is valued at about $1.6-million.

This year’s prize builds on earlier advances, starting with the initial development of quantum mechanics a century ago by pioneering theorists including Erwin Schrödinger, Werner Heisenberg and Paul Dirac. Their discoveries changed how physicists view electrons and other constituents of matter by showing they behave less like solid entities and more like waves of probability, where properties such as location and momentum come with a built-in degree of uncertainty. It is this uncertainty in position that can allow an electron to sometimes pop up on the other side of a barrier, which physicists in the 1930s dubbed “tunnelling.”

In 1962, British physicist Brian Josephson predicted the conditions under which pairs of electrons in a superconducting material could tunnel their way across a thin barrier. He was awarded the Nobel Prize for his work in 1973.

This laid a foundation for Dr. Clarke, 83, who was born in the U.K. and received his PhD at Cambridge University in 1968.

By 1984, he was established at the University of California, Berkeley, with a research team that included a French postdoctoral researcher, Dr. Devoret, and Dr. Martinis, who was then a PhD student.

Together the researchers constructed a superconducting circuit in which they demonstrated the quantum tunnelling effect with billions of pairs of electrons. Under such conditions the superconducting circuit can behave like a macroscopic version of a single atom.

The researchers then showed that, like an atom, the energy of the circuit occurs at discrete levels – another quantum effect with big implications.

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It’s these two developments together, and the way they show that quantum effects can reach well beyond the invisible world inside the atom, that were highlighted by the Swedish academy as the reason for the Nobel Prize.

Subsequent work showed that such superconducting circuits can be harnessed together and manipulated into different states using microwaves. In this form they are known as “transmons,” a popular choice for use as quantum bits – or qubits – the basic units of information that underpin quantum computers now in development and the subject of increasing investment by industry.

This year’s physics prize shows that “fundamental research is absolutely required for this endeavour,” said Alexandre Blais, director of Quebec’s Institut Quantique at the University of Sherbrooke. “The industrial effort we’re seeing is amazing, but it is not enough. The proof of that is that the companies are hiring all of our PhDs.”

In the mid-2000s, Dr. Blais worked with Dr. Devoret at Yale University on some of the research that followed from the team’s prizewinning discovery.

He said Dr. Devoret is the kind of intuitive thinker whose ability to make connections across different fields of expertise can lead to new insights – a characteristic that is not uncommon among Nobel laureates. For example, those who approach him with a quick question on one topic might unexpectedly find themselves learning about cosmology or 16th-century ceramics.

“Michel understands physics at a level that is not common,” Dr. Blais said.

This year’s selection marks a renewed focus on experimental quantum physics and material science. In 2024, the prize was awarded to University of Toronto computer scientist Geoffrey Hinton and U.S. physicist John Hopfield for their work on neural networks – computer algorithms that are the basis for artificial intelligence.

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Dr. Hinton was the seventh Canadian-based or Canadian-born scientist to have won the Nobel Prize in physics.

The others include Richard E. Taylor (1990), Bertram Brockhouse (1994), Willard Boyle (2009), Arthur McDonald (2015), Donna Strickland (2018) and James Peebles (2019).

On Monday, Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi were named winners of this year’s Nobel Prize in Physiology or Medicine for discoveries related to the immune system.

This year’s round of Nobel announcements continues on Wednesday when recipients of the chemistry prize are set to be revealed.