How a 40-Year-Old Experiment Forged Our Future
"The greatest discoveries often don't just answer questions—they change the questions we're asking."
Imagine holding a system in your palm that behaves like a single quantum particle, large enough to see with the naked eye, yet obeying the bizarre rules of the quantum world. This isn't science fiction—it's the breakthrough that earned three physicists the 2025 Nobel Prize, four decades after their pioneering work. Their journey from fundamental questioning to technological revolution exemplifies the very culture of discovery that the Nobel Prize aims to celebrate.
Quantum mechanics has long been the fundamental framework describing nature at its smallest scales—governing the behavior of atoms and subatomic particles. Yet its predictions defy our everyday experience. We don't see tennis balls tunneling through walls or cars existing in multiple places at once, yet at the quantum level, such phenomena regularly occur.
For decades, a fundamental question persisted in physics: how large can a system be and still exhibit quantum mechanical effects? Where is the boundary between the quantum world of potentialities and the classical world of definite realities? 4 6
This year's Nobel Laureates in Physics—John Clarke, Michel H. Devoret, and John M. Martinis—tackled this question head-on in the mid-1980s. Through elegant experiments with superconducting circuits, they demonstrated both quantum mechanical tunnelling and energy quantisation in a system "big enough to be held in the hand," as the Nobel Committee described it 1 4 .
Particles passing through energy barriers that should be impenetrable
Systems existing only at specific discrete energy levels
The laureates' groundbreaking work centered on a remarkable piece of experimental physics that made quantum effects visible at a macroscopic scale. Their apparatus consisted of an electrical circuit containing a key component: a Josephson junction, where two superconductors are separated by a thin insulating barrier just nanometers thick 4 6 .
| Component | Function |
|---|---|
| Superconductors | Materials that conduct electricity with zero resistance at low temperatures, allowing electrons to flow indefinitely 6 . |
| Josephson Junction | Thin insulating barrier sandwiched between two superconductors, enabling quantum tunnelling of Cooper pairs 4 6 . |
| Cooper Pairs | Pairs of electrons that behave as a single quantum entity in superconductors, forming a collective quantum state 6 . |
| Cryogenic System | Apparatus to cool the circuit to near absolute zero (-273°C), essential for maintaining superconducting states 6 . |
The team cooled their circuit to extremely low temperatures, causing electrons in the superconductors to form Cooper pairs. These pairs then coalesced into a single quantum state called a condensate—a macroscopic entity comprising billions of electron pairs behaving as one 6 .
In this state, the circuit could sustain electrical current flowing with zero voltage. The system became trapped in this zero-voltage state, analogous to a marble resting at the bottom of a bowl, prevented from escaping by the steep sides surrounding it 4 6 .
According to classical physics, the system lacked sufficient energy to escape this trap. Yet the researchers observed it doing exactly that—the current would suddenly switch to a voltage-carrying state. The system had quantum-tunneled through an energy barrier that should have been impenetrable 4 .
To eliminate any doubt, the team also demonstrated that the circuit's energy was quantised—it could only absorb or release specific discrete amounts of energy, a hallmark of quantum systems 4 .
| Scenario | Classical Physics Prediction | Quantum Physics Reality |
|---|---|---|
| A marble rolls toward a hill without enough speed to reach the top | The marble never reaches the other side; certain regions are forbidden 6 . | There's a probability the marble will appear on the other side, having "tunnelled" through the barrier 6 . |
| Electrical circuit in a low-energy state separated by an energy barrier | The circuit remains trapped in the zero-voltage state indefinitely 4 . | The circuit can spontaneously switch to a voltage-carrying state via quantum tunnelling 4 . |
The probability of a particle tunneling through an energy barrier decreases exponentially with barrier width and height.
The most remarkable aspect of this Nobel-winning work is how an experiment motivated by pure curiosity has fueled a technological revolution. The laureates weren't trying to build a quantum computer in the 1980s—they were probing fundamental questions about how nature operates 6 .
Original research focused on fundamental questions about quantum mechanics
Discovery of macroscopic quantum effects in superconducting circuits
Basis for quantum computing, sensors, and cryptography technologies
Yet their discoveries provided the essential foundation for one of today's most promising technologies: superconducting quantum computers 6 .
The very Josephson junctions used in their experiments have become the fundamental building blocks of quantum processors being developed by Google, IBM, and other leaders in the field. These quantum bits, or qubits, exploit the quantum properties these pioneers demonstrated to perform computations that would be impossible on classical computers 6 .
John Martinis, one of the 2025 laureates, exemplifies this bridge between fundamental science and applied technology. After his foundational work with Clarke and Devoret, he led Google's team that achieved quantum supremacy in 2019—demonstrating a quantum computer performing a calculation beyond the reach of the world's most powerful supercomputers 4 6 .
The 2025 Nobel season reveals a consistent pattern across disciplines: curiosity-driven research, often pursued without immediate concern for practical applications, regularly produces the most transformative breakthroughs.
In Chemistry, the laureates Susumu Kitagawa, Richard Robson, and Omar Yaghi were honored for developing metal-organic frameworks (MOFs)—highly porous crystalline structures that can capture carbon dioxide, harvest water from desert air, or store gases 1 3 . Like the physics laureates, they created an entirely new architecture for materials, opening possibilities they couldn't have fully anticipated when they began.
In Physiology or Medicine, Mary Brunkow, Fred Ramsdell, and Shimon Sakaguchi were recognized for fundamental discoveries about peripheral immune tolerance—how our immune systems avoid attacking our own bodies 1 . Their work, driven by basic curiosity about immune regulation, has since spawned new treatments for cancer and autoimmune diseases 1 2 .
| Field | Laureates | Key Discovery | Eventual Applications |
|---|---|---|---|
| Physics | Clarke, Devoret, Martinis | Macroscopic quantum tunnelling in circuits | Quantum computing, quantum sensors, quantum cryptography 4 |
| Chemistry | Kitagawa, Robson, Yaghi | Metal-organic frameworks (MOFs) | Carbon capture, water harvesting, gas storage 1 3 |
| Medicine | Brunkow, Ramsdell, Sakaguchi | Peripheral immune tolerance mechanisms | New treatments for autoimmune diseases and cancer 1 2 |
The story of the 2025 physics Nobel reminds us that transformative technologies often emerge from research pursued for its own sake, driven by curiosity rather than specific applications. As the laureates' work continues to enable new quantum technologies, it exemplifies the unpredictable return on investing in fundamental science.
Creating a Nobel culture doesn't mean rewarding only those whose work leads to practical applications. It means recognizing and supporting the human drive to understand nature at its most fundamental level—and trusting that such understanding will, in time, transform our world in ways we cannot predict.
The quantum circuit you can hold in your hand is more than a scientific breakthrough—it's a powerful reminder that the questions we ask today from pure curiosity may well shape the technologies that define our future.