Laureates for the Pulpit

Nobel Prizes for Preachers
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Physics · announced Tuesday, 7 October 2025

Quantum physics on a chip you could hold

“for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit”
  • John Clarke b. 1942 · University of California, Berkeley
  • Michel H. Devoret b. 1953 · Yale University, University of California, Santa Barbara, and Google Quantum AI
  • John M. Martinis b. 1958 · University of California, Santa Barbara, and Qolab

In plain terms

Quantum mechanics describes the very small. A single particle shut behind a barrier it lacks the energy to climb will sometimes turn up on the other side anyway. This is called tunnelling. Quantum systems also take in and give out energy only in fixed amounts, or quanta. Things made of vast numbers of particles show none of this. A ball thrown at a wall bounces back every time. So physicists have long asked how large a thing can be and still behave in a quantum way.

In 1984 and 1985, at the University of California, Berkeley, John Clarke, his postdoc Michel Devoret and his doctoral student John Martinis built a circuit from two superconductors, metals that when very cold carry a current with no resistance at all. Between them was a thin layer that does not conduct, an arrangement called a Josephson junction. In a superconductor the electrons pair up and move in step, so that billions of pairs behave like a single particle filling the whole circuit. The circuit starts out trapped in a state where current flows with no voltage. Every so often, at a moment no one can predict, it escapes by tunnelling, and a voltage appears. When the team fed in microwaves, the circuit absorbed only certain amounts of energy, exactly as quantum mechanics predicts.

The hard part was keeping the world out. Stray microwaves from warmer parts of the apparatus could mimic the effect, so the circuit had to be screened with great care, and every property of it measured independently, so that the results could be checked against theory with nothing adjusted to fit. They matched. The chip was about a centimetre across, and in effect it was an artificial atom with wires attached. Martinis later used its two lowest energy levels as the 0 and 1 of a quantum bit, and superconducting circuits are now one of the main techniques being explored in the effort to build a quantum computer.

1928
George Gamow explains a kind of radioactive decay by tunnelling.
1978
Anthony Leggett suggests that tunnelling by a whole superconducting circuit might be observed.
1984–85
Clarke, Devoret and Martinis run the experiments in Clarke’s laboratory at Berkeley.
1999
A team at NEC in Japan makes a superconducting circuit swing between two energy levels, an early step toward a quantum bit.
2014
Martinis and his team join Google to build a quantum computer. The effort later produces a 53-qubit chip that solves a problem judged out of reach for ordinary computers.
2025
The prize. Clarke, on the telephone to the press conference in Stockholm: “To put it mildly, it was the surprise of my life.”

Say it accurately

“Quantum physics shows things can pass through walls.”
Nothing on the chip passed through anything solid. The “barrier” is one of energy: the circuit sat in a state it did not have the energy to leave, and left it anyway. What crossed was the state of the whole circuit, and the sign that it had crossed was a voltage on a meter. A thrown ball will still bounce off the wall every time.
“They discovered quantum tunnelling.”
Tunnelling by single particles has been understood since 1928, and the superconducting junction they used earned Brian Josephson a Nobel Prize in 1973. The new thing was to see tunnelling, and fixed energy levels, in a system made of billions of particles acting together, on a chip about a centimetre across.
“They proved Schrödinger’s cat.”
Theorists such as Leggett compare the circuit to Schrödinger’s imagined cat, because quantum rules here govern something large made of many parts. But the committee notes that it is still many orders of magnitude smaller than a kitten, and that the quantum properties of a whole cat cannot be shown in a laboratory. No cat, alive or dead, is involved.
“This gave us the quantum computer.”
It gave one of the main routes toward one. Martinis later used the circuit’s two lowest energy levels as the 0 and 1 of a quantum bit, and Clarke said the basis of quantum computing relies “to quite an extent” on their discovery. The committee calls superconducting circuits “only one among a number of promising technologies” in the effort to build one, and speaks of “a future quantum computer.”
“Quantum chance means the world runs on luck, not on God.” Or the reverse: “Quantum chance is the gap where God acts.”
In the experiment no one could say when the circuit would tunnel, only how long it took on average, much as with the half-life of a radioactive atom. That is a finding about what can be predicted. Whether God governs events that physics can only count is a theological question, and the experiment does not answer it either way.

For preaching

  • “Their contributions are just overwhelming” Instance

    Romans 12:10 · Philippians 2:3–4

    Clarke ran the laboratory; Devoret was a postdoc and Martinis a doctoral student. After the announcement Clarke said: “I was in principle the leader of the group, of course, but their contributions are just overwhelming.” Martinis said they had taught him “how to do compelling experiments.” Here is a senior man giving the credit away, and a junior one giving thanks. “In honor prefer one another” (Romans 12:10, WEB).

  • Sowing without knowing which will prosper Instance

    Ecclesiastes 11:1 · Ecclesiastes 11:6

    In 1985 three physicists set out to answer a question about how far quantum rules reach. Fourteen years passed before anyone made a superconducting circuit swing between two energy levels, and nearly thirty before Martinis took his team to Google to build a quantum computer. That the work deserved a Nobel Prize, Clarke said, “had not occurred to us in any way.” “You don’t know which will prosper, whether this or that, or whether they both will be equally good” (Ecclesiastes 11:6, WEB).

  • Escape from a state that holds you Likeness

    Psalm 124:7 · Romans 7:24–25

    The circuit begins trapped. It lacks the energy to climb out, and on ordinary physics it would stay there for ever. Then it is out, and a voltage shows it. The image is vivid, but it proves nothing, and it breaks down at the point that matters: the circuit escapes by chance, and the psalmist’s escape is a deliverance. “Our soul has escaped like a bird out of the fowler’s snare” (Psalm 124:7, WEB).

  • Many moving as one Likeness

    Acts 4:32 · 1 Corinthians 12:12–27 · John 17:21

    In a superconductor the electrons pair up, and the pairs move in step, so that billions of them behave as a single particle filling the whole circuit. It is a picture of a body with one life. Mark where it fails: the pairs act as one by losing their individuality, and Paul’s body keeps every member distinct, the eye no less an eye for belonging.

On the Wesleyan shelf

  • Journal (16 October 1747)

    Wesley went with friends to see “what are called the electrical experiments,” and wrote that night: “How much these also confound those poor half thinkers, who will believe nothing but what they can comprehend? Who can comprehend, how fire lives in water, and passes through it more freely than through air?” He ends, “It is all mystery: if haply by any means God may hide pride from man!” His physics of electrical fire is long gone, and nothing in it anticipates tunnelling. His posture survives: an electrical apparatus doing what common sense says it cannot was, for him, an occasion for humility, not for disbelief.

  • On Divine Providence (sermon on Luke 12:7)

    Wesley answers those who allow God a general providence over great events but not a care for small ones. His reply is that “great and little are merely relative terms, which have place only with respect to men” (§26), and he sums up with Augustine: God presides over each as over all, and over all as over each (Ita praesidet singulis sicut universis). Earlier he says God “sees every atom of his creation,” while “we see only the surface” (§10). His subject is God’s care, not physics. But a prize about whether the rules of the small reach up to the large can open a sermon on Luke 12:7, so long as the preacher does not claim the experiment as evidence for it.

Sources: Nobel press release · Nobel popular information · Nobel scientific background (pdf) · University of California · UC Berkeley Physics · Physics World