Nobel Prize in Physics 2025

What these laureates did is show that the quantum properties we used to think only worked at the microscopic level can also appear in the real world (macroscopic level) under certain conditions.

From the behavior they observed in superconducting circuits, they saw clear signs of quantum tunneling and energy discretization happening in those circuits.

To give some backstory:

Tunneling is like throwing a ball toward a hill. If you throw it with enough energy, it goes over to the other side. If not, it rolls back. In the quantum world, though, things work differently. When a quantum particle approaches a barrier, it’s not an all-or-nothing situation. Because a particle can act as both a particle and a wave, there is a small chance it can tunnel through the barrier and appear on the other side, even without enough energy to climb over it.

Energy discretization means a quantum particle can only exist at certain energy levels. For example, it can have energy levels like 3 or 6 or 9, but not 4 or 5 or 7. These are the kinds of behaviors we usually see at the atomic level.

What makes this work so exciting is that these scientists showed we can observe those same quantum effects at the macroscopic scale, inside a superconducting circuit made of billions of electrons.

That’s really awesome, because one of the biggest challenges for current quantum computers is decoherence, which means qubits losing their information due to noise from their surroundings. Seeing quantum effects persist in circuits like this gives hope for building more stable and less error-prone superconducting quantum computers, the kind that companies like IBM and Google are working on.