The Nobel Prize for 2025 was awarded on Tuesday to a trio of physicists—John Clarke, Michel H. Devoret, and John M. Martinis “for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit".
The Royal Swedish Academy's award of 11 million Swedish kronor (roughly $1.17 million) will be divided equally among them.
Through their experiments, the three physicists have shown that quantum tunnelling—or the process by which subatomic particles "pass" through a potential energy barrier, despite lacking the energy to overcome the barrier (in classical physics terms)—could be demonstrated on a scale "big enough to be held in the hand".
In simpler terms, they have just proven that even man-made circuits could act like quantum systems, which will be a huge influence in tech giants' race towards quantum computing.
“It is wonderful to be able to celebrate the way that century-old quantum mechanics continually offers new surprises. It is also enormously useful, as quantum mechanics is the foundation of all digital technology,” says Olle Eriksson, Chair of the Nobel Committee for Physics.
What they discovered
The trio's story goes back to 1984-85. Clarke, Devoret, and Martinis used an electrical circuit with two superconductors—placed on a 1-centimetre-long chip—in a series of experiments at the University of California, Berkeley.
A superconductor is a component that can conduct an electric current with zero resistance, meaning no loss of energy and maximum efficiency.
They separated the two superconductors with a thin layer of material that did not conduct any current at all.
The experiments showed that they could control and examine a phenomenon in which all the charged particles in the superconductor work together, as if they were a single particle filling the entire circuit.
This macroscopic (visible to the human eye) system is initially in a state in which current flows without any voltage.
The system is trapped in this state, as if behind a barrier that it cannot cross.
In the experiment, the system shows quantum properties by managing to escape the zero voltage state through quantum tunnelling. The change in the state of the system is detected through the appearance of a voltage.
The three laureates
British-born John Clarke, born in 1942, is an emeritus professor of Physics at the University of California, Berkeley.
Devoret, born in France, is a professor at Yale University and the University of California, Santa Barbara, where Martinis is also a professor.
"My feelings are that I'm completely stunned. Of course it had never occurred to me in any way that this might be the basis of a Nobel Prize," Clarke told the Nobel press conference by telephone.
"I'm speaking on my cell phone and I suspect that you are too, and one of the underlying reasons that the cell phone works is because of all this work."