From a Mysterious Tunnel to Quantum Computers: The 2025 Nobel Prize in Physics Awarded to Three Pioneers of Quantum Technologies
On October 7th, the Royal Swedish Academy of Sciences in Stockholm announced the 2025 Nobel Prize in Physics. The award went to Prof. John Clarke from the University of California, Berkeley, Prof. Michel Devoret from Yale University, and Prof. John Martinis from the University of California, Santa Barbara. They were honoured for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit, which laid the foundations for modern quantum technologies 鈥� from quantum computers to ultra-precise sensors.
According to Dr Ma啪ena Mackoit-Sinkevi膷ien臈, a researcher at the Faculty of Physics of 糖心vlog蜜桃 (VU), this year鈥檚 Nobel Prize stands out not only for its scientific significance but also for its symbolic value 鈥� marking the centenary of quantum physics. 鈥楺uantum physics has fundamentally transformed our understanding of matter and its behaviour. The work of this year鈥檚 laureates meaningfully closes this century-long journey, as it bridges the theoretical foundations of quantum physics with technologies that make it possible to control quantum phenomena in practice.鈥�
When particles pass through walls
鈥楢t its core, quantum physics rests on two fundamental principles. The first is the wave鈥損article duality, meaning that particles can behave both as discrete particles and as waves that interact and interfere with one another. The second is that their states can be precisely described mathematically through the Schr枚dinger equation. This theory is not only mathematically beautiful 鈥� it also allows us to predict surprising phenomena that classical physics simply cannot explain,鈥� noted Dr Mackoit-Sinkevi膷ien臈.
According to the researcher, one of the most intriguing of these phenomena is quantum tunnelling. In the classical world, a ball rolling up a hill will stop if it lacks enough energy to cross the peak. But in the quantum realm, a particle can 鈥榯unnel鈥� through a barrier, as if passing straight through a wall. For a long time, this effect existed only in theory. However, in the second half of the 20th century, scientists succeeded in demonstrating it experimentally: Leo Esaki showed quantum tunnelling in semiconductors (tunnel diodes), Ivar Giaever observed it between superconductors separated by a thin insulating layer, and Brian Josephson provided the theoretical explanation and predicted current tunnelling without applied voltage. For these scientific breakthroughs, they were awarded the 1973 Nobel Prize in Physics.
The 2025 Nobel Prize granted to Clarke, Devoret, and Martinis builds directly upon this earlier work 鈥� yet also marks a revolutionary leap forward. The laureates demonstrated that an entire macroscopic system, i.e. a superconducting quantum circuit, can behave as a single quantum system: collectively tunnelling between states and exhibiting discrete energy levels, much like individual particles. This proved that quantum mechanics applies not only to the microscopic world but also to macroscopic systems, paving the way for the creation of modern superconducting qubit鈥揵ased quantum computers.
From superconductivity to quantum computation
鈥楾his year鈥檚 laureates 鈥� John Clarke, Michel Devoret, and John Martinis 鈥� provided a striking demonstration of how this effect operates on a macroscopic scale. They designed and refined systems in which particles flowing through superconductors behave quantum mechanically 鈥� not as individual entities but as a single collective system. In these systems, electrons form Cooper pairs, a concept first described in 1957 by other Nobel laureates 鈥� John Bardeen, Leon Neil Cooper, and John Robert Schrieffer 鈥� who developed the BCS theory of superconductivity (awarded the 1972 Nobel Prize in Physics). These Cooper pairs move without resistance, forming a unified quantum state, meaning that countless particles act as one,鈥� said the VU researcher.
In announcing the award, the Nobel Committee stated that these studies 鈥榩rovided opportunities for developing the next generation of quantum technology, including quantum cryptography, quantum computers, and quantum sensors鈥�. Dr Mackoit-Sinkevi膷ien臈 added that everything once derived mathematically has now been confirmed experimentally and technologically through the laureates鈥� work.
Quantum phenomena shaping a new technological era
According to the VU physicist, these insights have become the core of today鈥檚 quantum computers: 鈥楩or such devices to operate, they must be cooled almost to absolute zero (just a few tens of millikelvins) to eliminate thermal noise and maintain stable quantum states. These systems use Josephson junctions 鈥� microscopic barriers through which Cooper pairs tunnel, generating measurable voltages. This process enables the creation and control of quantum bits, or qubits, which can exist not only in the 0 or 1 state, but in a superposition of both simultaneously.鈥�
鈥業t is one of the earliest quantum technology platforms, proposed in the late 20th century, and remains the area where the most significant advances have been made: companies like IBM and Google base their quantum processors on superconducting circuits. Other technologies, such as photonic systems, trapped ions, ultracold atom lattices, and diamond-based qubits, also exist, but this platform was the first to provide practical evidence that quantum effects can be controlled through engineering,鈥� explained Dr Mackoit-Sinkevi膷ien臈.
She believes this year鈥檚 Nobel laureates have successfully shown that the boundary between classical and quantum physics is disappearing: 鈥楺uantum effects are now observed in increasingly larger and more complex systems, and what seemed like purely theoretical exotic phenomena just a few decades ago has become the foundation for an entirely new technological era. Their discoveries have paved the way for hundreds of research groups and start-ups developing practical quantum applications 鈥� from ultra-precise measurements to breakthroughs in information security and computing.鈥�