Why in news?
The 2025 Nobel Prize in Physics was awarded jointly to John Clarke, Michel H. Devoret and John Martinis for showing that phenomena predicted by quantum mechanics can occur at a macroscopic scale in electrical circuits. Their experiments revealed quantum tunnelling and energy quantisation in systems large enough to see with the naked eye, opening the door to quantum computing.
Understanding the discoveries
- Quantum tunnelling: In the microscopic world, particles can “tunnel” through barriers that they should not cross according to classical physics. The laureates demonstrated that entire electrical circuits can exhibit similar behaviour.
- Energy quantisation: Electrons in a circuit do not have arbitrary energy but jump between fixed levels, creating discrete steps in current flow.
- Macroscopic scale: These quantum effects were observed in circuits with trillions of atoms, proving that quantum mechanics is not limited to atoms and molecules.
Significance and applications
- Quantum computing: The discoveries paved the way for superconducting qubits, which are the basis of many current quantum computers.
- Precision measurements: Understanding macroscopic quantum effects improves sensitive devices like SQUIDs (superconducting quantum interference devices) used in geology and medicine.
- Fundamental physics: The experiments confirm that quantum laws govern even large systems, enriching our understanding of nature.