Trio awarded 2025 Nobel Prize in Physics for quantum tunneling work
The 2025 Nobel Prize in Physics has been awarded to John Clarke, Michel Devoret, and John Martinis for their pioneering research on quantum tunneling in superconducting circuits. Their 1985 experiments demonstrated how quantum effects apply to complex systems, laying the foundation for modern quantum computers. Clarke expressed surprise at the recognition, noting the unexpected impact of their discovery.
In 1985, John Clarke, Michel Devoret, and John Martinis, then at the University of California, Berkeley, conducted experiments on Josephson junctions—superconducting wires separated by an insulating material that earned Brian Josephson the 1973 Nobel Prize in Physics. They measured the properties of charged particles moving through these junctions and found that the particles behaved as a single entity with distinct energy levels, a quantum effect. The researchers also observed a voltage indicating that particles had tunneled through the insulating boundary, confirming quantum tunneling in a macroscopic system.
This breakthrough showed that quantum behaviors, previously observed only in single particles, could extend to electronic circuits traditionally governed by classical physics. Such findings revolutionized quantum science by enabling precise tests of quantum mechanics on silicon chips. As Clarke stated, “Our discovery, in some ways, is the basis of quantum computing.”
Their work directly contributed to the development of superconducting qubits, the building blocks of today's quantum computers. Companies like Google and IBM now use hundreds of such qubits in their machines. Martinis and Devoret later joined Google Quantum AI, which in 2019 demonstrated a superconducting quantum computer achieving quantum advantage over classical systems.
Upon learning of the award, Clarke told the Nobel committee, “I’m completely stunned. It had never occurred to me in any way that this might be the basis of a Nobel prize.” He added that the significance of their 1985 research was not apparent at the time: “It had not occurred to us in any way that this discovery would have such significant impact.”
Quantum particles exhibit strange properties, including probabilistic nature and discrete energy levels, leading to phenomena like tunneling through barriers—ideas explored by early physicists such as Erwin Schrödinger.