Nobel Prize in physics goes to three scientists who discovered bizarre quantum effect on large scales
The 2025 Nobel Prize in Physics has been awarded to a trio of researchers for discovering quantum mechanics on a whole new scale – big enough to fit in your hand.
John Clarke from the University of California at Berkeley, Michel H. Devoret from Yale University and the University of California at Santa Barbara, and John M. Martinis from the University of California at Santa Barbara, received the prestigious prize “for the discovery of macroscopic quantum mechanics tunneling and the quantification of energy in an electrical circuit.”
“To put it mildly, it was the surprise of my life,” Clarke said by phone. during a press conference. “I am of course completely stunned. It never occurred to me that this could be the basis for a Nobel Prize.”
He said his discovery (which is the basis of the advanced microchips found in many modern technologies, including smartphones) is being used for the further development of quantum computers.
Clarke, Devoret and Martinis conducted experiments in which they were able to demonstrate quantum mechanics tunneling and quantified energy levels in an electrical circuit “large enough to fit in your hand,” according to a report. statement published by the Royal Swedish Academy of Sciences.
Quantum tunneling allows particles to pass through seemingly impassable barriers. Indeed, in quantum physics, particles exist simultaneously in the form of waves and particles; these waves are the projected probabilities of the existence of the particle in a given space.
Just as a wave breaking against a groin at sea would result in a smaller wave propagating to the other side, particles that exist as waves also have some probability of existing on the other side of a barrier. It is this ability that allows electrons to jump between layers of materials that would otherwise be impassable, at least according to large-scale physical laws.
Before the researchers’ discovery, quantum tunneling had been observed in single particles, but physicists soon wondered whether multiple particles could tunnel at the same time. One way to do this would be to make the materials extremely cold, turning them into superconductors by causing electrons to bond together in what is called “Pairs of coopers“.
Cooper pairs follow different rules of quantum mechanics than solitary electrons. Instead of stacking on top of each other to form shells of energy, they act like particles of light, or photons, of which an infinite number can occupy the same point in space at the same time. If enough of these Cooper pairs are created in a material, they become a superfluid, flowing without any loss of energy due to electrical resistivity.
To make their discovery, the researchers sandwiched two superconductors between a thin insulating barrier, creating an experimental setup known as the Josephson junction. Working together in the mid-1980s, the scientists shielded their own Josephson junction from interference before introducing a weak electric current into it.
Initially, the voltage across this circuit was zero, indicating that no current was flowing through the barrier. But by repeating their experiment several times, the researchers quickly discovered that a voltage appeared across the device at different times. This showed that the electrons were indeed tunneling through the system, acting as a single particle on a large scale.
The emission of microwaves intended to be absorbed by the electrons showed that, although their collective state was macroscopic, the electrons in Cooper pairs had discrete, quantized energy levels.
This discovery has had many practical applications in physics and beyond. The collective system is called an artificial atom, from which many quantum experiments and technologies have been developed.
“It’s wonderful to be able to celebrate how centuries-old quantum mechanics continually offers new surprises,” Olle Erikssonchairman of the Nobel Committee for Physics, said in the statement. “It is also extremely useful, because quantum mechanics is the foundation of all digital technology.”
