Quantum Circuits as Artificial Atoms: 2025 Nobel Physics Laureates Chart the Future of Superconducting Qubits

The 2025 Nobel Prize lectures in physics brought cutting‑edge quantum research to a global audience as laureates John Clarke, Michel H. Devoret and John M. Martinis took the stage at Aula Magna, Stockholm University. The three physicists were honoured “for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit,” a breakthrough that showed quantum effects can be observed and controlled in devices large enough to see with the naked eye.​

In his lecture “From SLUGs to macroscopic quantum phenomena,” John Clarke traced the path from precision superconducting sensors to landmark experiments where a superconducting circuit tunneled through an energy barrier without the classical energy needed to climb over it. These results confirmed that entire electrical circuits, hosting billions of electrons, can behave as single quantum objects, overturning the intuition that quantum behaviour is restricted to microscopic particles. Clarke also highlighted how these macroscopic quantum systems paved the way for ultra‑sensitive magnetometers and amplifiers used in both fundamental physics and emerging quantum technologies.​

Michel H. Devoret’s talk, “From macroscopic quantum phenomena to artificial atoms,” focused on how superconducting circuits with Josephson junctions can be engineered to have discrete energy levels, mimicking the behaviour of atoms. By tailoring the circuit design and driving it with microwaves at carefully chosen frequencies, researchers can promote the system between quantised energy states, directly demonstrating energy quantisation in a macroscopic device. Devoret stressed that this ability to design “artificial atoms on demand” has become a powerful platform for exploring quantum mechanics and building the core elements of quantum information processors.​​

John M. Martinis, in his lecture “Prehistoric Superconducting Qubits,” recounted the early, often fragile incarnations of superconducting qubits and the multi‑decade effort required to turn them into reliable information carriers. He outlined how advances in materials, circuit layouts and control electronics have steadily improved coherence times and reduced error rates, enabling the first demonstrations of quantum advantage with superconducting processors. Looking ahead, Martinis argued that scaling these systems to the millions of qubits needed for fault‑tolerant quantum computing will demand continued innovation in both hardware design and error‑correction schemes, but rests firmly on the laureates’ foundational discovery that quantum rules can govern macroscopic circuits.​​

Beyond celebrating past achievements, the lectures underscored the practical impact of macroscopic quantum tunnelling and energy quantisation in electrical circuits on future technologies. Superconducting artificial atoms now sit at the heart of many leading quantum computing efforts, while related devices promise improvements in sensing, communication and metrology. For students and researchers in Stockholm and worldwide watching the live stream, the event offered a rare, coherent narrative linking fundamental quantum discoveries to the rapidly evolving field of quantum engineering.​​

Source: Nobel Prize lectures in physics 2025, Stockholm University and NobelPrize.org