John Clarke, Michel Devoret and John Martinis win the 2025 Nobel Prize for Physics

The Royal Swedish Academy of Sciences has awarded the 2025 Nobel Prize in Physics to John Clarke, Michel H. Devoret, and John M. Martinis for their pioneering work that bridges the gap between the microscopic and macroscopic worlds of quantum physics.

The trio received the honour "for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit." Their groundbreaking experiments have deepened our understanding of how quantum mechanics - usually confined to atoms and subatomic particles - can manifest in systems large enough to be held in one's hand.

A long-standing question in physics has been how large a system can get before quantum effects disappear. Clarke, Devoret, and Martinis provided a stunning answer in the 1980s by demonstrating quantum tunnelling and quantised energy levels in a macroscopic electrical circuit.

Their experiment used superconducting circuits separated by a thin insulating layer - known as a Josephson junction - allowing current to flow without resistance. By carefully refining and measuring this system, they observed quantum tunnelling: a phenomenon where a particle - or in this case, the collective current - can pass through an energy barrier that it should not, according to classical physics.

They further discovered that the system's energy changes occurred in discrete steps, a clear hallmark of quantum behaviour. This proved that quantum mechanics governs not just microscopic particles but also larger, engineered systems - a finding that opened the door to practical quantum technologies.The Nobel Committee hailed their work as a "milestone in demonstrating the tangible, measurable nature of quantum mechanics."

"It is wonderful to be able to celebrate the way that century-old quantum mechanics continually offers new surprises," said Olle Eriksson, Chair of the Nobel Committee for Physics. "It is also enormously useful, as quantum mechanics is the foundation of all digital technology."

The laureates' discoveries have laid the scientific groundwork for quantum computing, quantum cryptography, and advanced quantum sensors, all of which are now central to modern research and emerging industries.

This year's Nobel announcement follows 2024's Physics Prize, which went to John J. Hopfield and Geoffrey Hinton for their foundational contributions to machine learning and artificial neural networks - technologies shaping today's AI revolution.

The 2025 Nobel week began with the award in Physiology or Medicine, given to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their discoveries explaining how the immune system avoids attacking the body's own organs.