In a triumph that bridges the ghostly world of quantum mechanics with the tangible reality of everyday objects, the Royal Swedish Academy of Sciences has awarded the 2025 Nobel Prize in Physics to John Clarke (UC Berkeley), Michel H Devoret (Yale and UC Santa Barbara), and John M Martinis (UC Santa Barbara) for a groundbreaking discovery that defied intuition: quantum effects can manifest in circuits large enough to hold in your hand.
Their work – conducted nearly four decades ago but only now fully appreciated for its revolutionary implications – proved that the bizarre rules governing electrons and photons aren’t confined to the atomic scale. They can echo through human-made circuits visible to the naked eye, opening the door to the quantum technologies now reshaping our world.
When quantum physics went macro
For decades, physicists assumed quantum weirdness, like particles tunnelling through impenetrable barriers or existing only in discrete energy levels, vanished in larger systems, drowned out by classical physics. But in a series of elegant experiments between 1984 and 1985, the laureates turned that assumption on its head.
Using superconducting circuits cooled to near absolute zero, they engineered a device centred on a Josephson junction: two superconductors separated by an ultra-thin insulating layer. In this setup, billions of electrons moved in perfect unison, behaving not as individuals but as a single quantum entity, a “macroscopic quantum object.”
This collective state could sit in a zero-voltage condition, trapped like a ball in a valley behind a hill. According to classical physics, it should stay there – unless given enough energy to climb over. But quantum mechanics offered a shortcut: tunnelling.
And tunnel it did.
The team observed the circuit spontaneously “leaking” out of its trapped state, not by climbing, but by tunnelling through the energy barrier, producing a measurable voltage. Even more strikingly, they showed the system absorbed and emitted energy only in precise, quantised steps, just like an atom.
“It was as if we’d built a tiny quantum atom out of wires and metal,” said John Martinis in a post-announcement interview. “Except this ‘atom’ was big enough to see under a microscope—and eventually, to power a new technological revolution.”
From lab curiosity to quantum revolution
What began as a profound test of quantum theory has become the bedrock of today’s second quantum revolution. The circuits pioneered by Clarke, Devoret, and Martinis are the ancestors of superconducting qubits, the core components of quantum computers like Google’s Sycamore and IBM’s Eagle processors.
Martinis, who later led Google’s quantum hardware team, famously demonstrated “quantum supremacy” in 2019 using technology rooted in these very principles. Devoret’s theoretical and experimental frameworks helped decode quantum noise and error mechanisms, while Clarke’s innovations in ultrasensitive measurement laid the groundwork for quantum sensors capable of detecting magnetic fields from single neurons.
“Transistors in your phone already rely on quantum mechanics,” noted Olle Eriksson, Chair of the Nobel Committee for Physics. “But this year’s laureates showed we could engineer quantum behaviour into macroscopic systems. That insight didn’t just answer a deep question, it gave us the tools to build the future.”
A prize that echoes through time
The 2025 Nobel Prize comes at a pivotal moment. Governments and tech giants are investing billions into quantum computing, secure communication, and ultra-precise sensing, all fields made possible by controlling quantum states in engineered circuits.
And yet, the laureates’ original motivation was pure curiosity: How big can something be and still obey quantum laws?
“The beauty is that nature said ‘yes’, even at scales we can touch,” said Devoret from Yale. “Quantum mechanics isn’t just for atoms. It’s for circuits, for chips, and soon, perhaps, for society.”
The trio will share the 11 million Swedish kronor prize (approximately $1.05 million USD), but their true legacy lies in the labs, startups, and data centres worldwide where their 1980s experiments now power the quantum age.
As Clarke, now 83, reflected: “We didn’t set out to build a quantum computer. We just wanted to listen to what the universe was whispering. Turns out, it was shouting.”