Nobel Prize in Physics 2025

• The Royal Swedish Academy of Sciences has awarded the 2025 Nobel Prize in Physics to John Clarke (UK), Michel Devoret (France), and John Martinis (USA) for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit.
• Their discovery confirmed that quantum phenomena, once thought limited to subatomic particles, can also manifest in macroscopic systems, expanding the boundaries of quantum mechanics.
• At the heart of their breakthrough was a device known as a Josephson junction, which consists of two superconducting materials separated by a thin insulating layer. In this setup, the trio was able to precisely control and measure the quantum state of the electrical circuit, showing that an entire electrical circuit could exhibit quantum tunnelling when cooled to extremely low temperatures.

About Macroscopic Quantum Tunnelling (MQT)

• Quantum mechanics permits a particle to pass directly through a barrier via a process known as quantum tunnelling.
• Macroscopic quantum tunnelling occurs when a large-scale system crosses an energy barrier (quantum tunnelling) without having enough classical energy to do so.
  • Energy Barrier is a region of higher potential energy that classically prevents particles or systems from moving across.

• Quantum Principle: This tunnelling phenomenon occurs because of wave-particle duality, where matter behaves both as a particle and a wave.
• Significance: Demonstrating MQT in visible circuits bridges the gap between quantum and classical physics, thereby paving the way for the development of quantum technologies.

Josephson Junction

• A Josephson junction consists of two superconductors separated by an ultrathin insulating layer that allows quantum tunnelling of electron pairs.
• Mechanism: Cooper pairs pass through the insulating barrier via Quantum Tunnelling, producing a supercurrent to flow without any applied voltage.
• Qubits: These junctions form the building blocks of quantum bits (qubits) used in quantum computers.
• Innovation: Clarke and his team improved shielding and cooling techniques to precisely isolate the setup from interference and confirm quantum effects on a macroscopic scale.

Significance of the Discovery

• These discoveries help bridge the conceptual gap between quantum physics and macroscopic engineered devices.
• They are foundational for quantum technologies such as quantum computing, quantum sensing, and quantum cryptography.

Read More > Quantum Physics, Nobel Prize in Chemistry 2025.