Three scientists win Nobel in Physics for breakthroughs in quantum mechanics

The 2025 Nobel Prize in Physics has been jointly awarded to three visionary scientists—John Clarke, Michel H. Devoret, and John M. Martinis—for their groundbreaking work that successfully brought the bizarre, yet fundamental, rules of quantum mechanics out of the subatomic realm and into the macroscopic world of electric circuits. The Royal Swedish Academy of Sciences lauded the trio “for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit,” recognizing a triumph in modern physics that shatters the traditional view of quantum phenomena being restricted only to atoms and particles. Their achievement, decades in the making, opens radical new avenues for engineered quantum technologies.

For generations, physicists have wrestled with a foundational question: can the strange effects of quantum mechanics—like uncertainty and wave-particle duality—emerge in large, tangible systems visible to the human eye? This year’s laureates answered with a resounding "Yes." Their pivotal work, conducted in a series of painstaking experiments during the 1980s, involved constructing highly sensitive superconducting circuits using a core component known as Josephson junctions, where two superconducting materials are separated by an ultra-thin insulating layer.

The true breakthrough came from meticulously observing how the collective charge within these sophisticated circuits behaved. Instead of acting as a collection of isolated particles following classical physics, the entire circuit—large enough to be held—functioned as a single, unified, macroscopic quantum object. This demonstration was the key that unlocked the visualization of quantum behavior on an unprecedented scale.

The most dramatic proof of their success was the observation of macroscopic quantum tunnelling. In the quantum world, tunnelling is a process where a system doesn't jump over an energy barrier, but rather passes directly through it. Clarke, Devoret, and Martinis demonstrated this phenomenon occurring not at the scale of an electron, but in the entire, visible electric circuit, confirming that quantum rules were indeed governing the bulk properties of their engineered device.

Even more remarkably, the scientific team provided compelling evidence for energy quantisation in their macroscopic circuit. This fundamental tenet of quantum theory states that energy can only be absorbed or emitted in discrete, fixed amounts, or quanta. By proving that their electric circuit’s energy states were similarly quantized, the laureates provided a robust and tangible confirmation of quantum mechanics operating far outside its traditionally accepted confines.

By successfully making quantum effects manifest at a scale far beyond individual atoms, the work of Clarke, Devoret, and Martinis has profound implications for the future. Their achievement has laid the foundational blueprint for creating engineered quantum devices, including the superconducting qubits that form the basic building blocks of many of today's most powerful and advanced quantum computers, truly bringing quantum physics into the realm of practical technology.