Imagine studying a single marble trapped in a room on Earth from outer space. For the marble to move to the other side of a wall, it would need an external force giving energy to break through. Now imagine, the marble actually moves through the wall without external energy. This illustrates the bizarre phenomenon of quantum tunnelling that physicists are studying at the microscopic level of protons and electrons. 

In the realm of classical physics, for a particle to move, it must overcome an energy barrier, but bounces back to its original place if it doesn’t have enough energy. Classical physics states that this is because their motion is governed by the laws of conservation of energy and momentum. This relies on continuous (non-discrete) energy values that are certain, such as potential energy transforming into kinetic energy and vice versa.

Nobel-winning research turned quantum mystery into a measurable tool, laying the foundation for revolutionary computing technology

In the realm of quantum physics, a particle behaves less like a marble in a room, but rather, a blur of probability. Quantum theory states that a particle is able to penetrate through a potential energy barrier that is higher in energy than the particle’s kinetic energy, defying classical physics. A particle has a range of possible locations and speeds, but the knowledge of both is unknown at any given point in time. Even so, there is a small non-zero chance that the particle appears on the other side of a seemingly impenetrable wall, as if it’s tunneling its way through an unbreachable mountain, without exorbitant energy. This particle behavior is called the “tunneling effect”, a process occurring nearly instantaneously . Instead, quantum mechanisms rely on inherent, discrete energy values that act as probabilistic models. It’s not that a particle has enough energy; it’s the fundamental quantum uncertainty of its unique positioning that allows a particle to perform this extraordinary feat. 

Three physicists, John Clarke, Michel Devoret, and John Martinis, have been working to understand quantum tunnelling behavior since 1985 . This team pioneered the use of the Josephson junction device , or two superconducting loops, which is a closed-circuit where electricity flows without resistance at ultra-low temperatures. In this system, the scientists could trigger, measure, and manipulate particles with precision. By controlling the flow of a current with this device, they recorded a significant voltage spike demonstrating an occurrence of the tunnelling effect. Essentially, they proved that the tiny, low-energy circuit could break into a higher-energy state represented by the sudden increase in voltage. In classical physics, this environment would remain stuck with nothing to measure.Following this breakthrough, Clarke, Devoret, and Martinis were awarded the 2025 Nobel Prize in Physics for their remarkable work in turning the “quantum tunneling” phenomenon into a measurable and precise tool for determining a system’s quantum state. This work lays the foundation for the entire field of superconducting quantum circuits, a blueprint for quantum bits, or “qubits,” that are the building blocks of today’s most advanced quantum computers. Supercomputers can leverage qubits to hold more information and solve complex problems faster than classical computers that use binary bits (0 or a 1). Apart from the future of supercomputers, quantum tunnelling can also explain the mysteries of many cellular processes in nature . Examples include spontaneous mutations in DNA, prebiotic chemistry, and the chemical reactions that assembled the first self-replicating molecules on primitive earth. The profound implications of this Nobel-winning work in quantum and classical physics has opened a gateway for scientists and engineers to create revolutionary technology in a novel approach for understanding complex particle behavior.