Understanding quantum mechanics: How this year's Nobel Prize winners brought quantum mechanics within reach
Quantum mechanics is everywhere, from powering the phone you’re reading this on to the galaxies that are formed with colliding stars, everything has to be understood at a molecular level that is based on the principles of quantum mechanics
Understanding quantum mechanics is paramount in producing the technologies of the future. The complex phenomenon of quantum mechanics is often revered but rarely understood, and research in this frontier is crucial in bringing forth greater comprehension of how the universe works.
Quantum mechanics is everywhere, from powering the phone you're reading this on to the galaxies that are formed with colliding stars, everything has to be understood at a molecular level that is based on the principles of quantum mechanics.
So in this regard, the winners of the Nobel Prize 2025 in Physics, John Clarke, Michel H. Devoret, and John M. Martinis, pursued a worthy endeavour and took a step in the direction of understanding how the world, not even observable under a microscope, actually works.
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A bit of quantum mechanics
Before you start reading, it should be very evident that this article in no way, shape, or form hopes to educate you about quantum mechanics. What is done here is to give you a layman's version, just so you understand the significance of the discovery and not dissolve your brain reading this piece.
This newer understanding has the potential to bring forth new ideas for quantum computing and sharpen its tools for more complex problem-solving, data extraction, and processing
There are some fundamental principles of physics we all understand. Gravity, velocity, force, or energy are all concepts we are familiar with and can visualise easily. However, there is one world where these principles, commonly known as Newtonian mechanics, do not work.
The world in question is extremely and unimaginably small. Think of the smallest thing you know of, maybe an atom?
Well, quantum mechanics deals with elements more foundational than a whole atom itself, as it deals with fundamental elements such as the electron, neutron, positron, and even smaller particles such as the quark. These are subatomic elements and while having mass, energy, and movement, they do not behave like the bigger elements.
The principles involved in describing the nature of such subatomic particles are known as quantum mechanics. The millions of transistors used inside a chip today are based on quantum mechanical principles.
The layers of atoms bonding together to form a cohesive element are guided by quantum rules. And not to mention the universe we see today, the tangible solid objects, all are formed at a subatomic level using the principles of quantum mechanics. Therefore, not having a professional interest in understanding its discoveries should in no way discourage you from taking an interest, because it affects your life more than you can ever imagine.
The prize-winning discovery
When you throw a ball straight at a wall, naturally it bounces back, as facing a barrier forces it to revert and stop. However, electrons or neutrons in motion can hardly be stopped using any physical object. They exist well beyond the physical space of solid objects, as the objects themselves are composed of them.
John Clarke, Michel H. Devoret, and John M. Martinis conducted an experiment to observe what actually can stop a moving subatomic particle. They used a Josephson junction, which consists of two superconductors separated by a thin insulating barrier. In a superconductor, the passing current — in other words, electrons — will not have any resistance. The barrier, made of a non-conductive material, was meant to see if the electrons could still pass through it.
It was found that the subatomic particles could tunnel through the non-conductive layer, and they did so as quantum theory predicted. The current behaved as if a single collective particle — a group of paired electrons known as Cooper pairs — was flowing through the entire circuit.
They also behaved so as to pass without the need for an initial voltage to be present. The system itself initially ran without any voltage — the difference of potential energy that is believed to provide the need for the electron to flow.
This demonstrated a zero-voltage state, which is a key feature of the Josephson effect. Later, when the system escaped this state through quantum tunnelling, a measurable voltage appeared. This brought forth a greater understanding of how electrons behave at a subatomic level.
Normally, when you hear that your electric socket provides 220 volts, it means the difference in potential energy between your socket and the electric device you are about to plug in is 220. This difference is crucial; otherwise, there would be no need for the electrons to move from high voltage to low voltage; thereby, there would be no need for electricity to generate.
In the quantum world, however, electrons were producing current — meaning they were passing not just through a superconductor, where they were expected to pass, but also through a non-conductor, and that too without the presence of any initial voltage.
But in a twist, changes in the system were observed as it gradually built up its own voltage as it absorbed more and more energy from presumably the moving particles. This absorption is coined as quantised, meaning that it only absorbs or emits specific amounts of energy. The experiment showed macroscopic quantum tunnelling — a quantum event happening in a system large enough to be seen with the naked eye.
The impact on industry
"It is wonderful to be able to celebrate the way that century-old quantum mechanics continually offers new surprises. It is also enormously useful, as quantum mechanics is the foundation of all digital technology," Olle Eriksson, chair of the Nobel Committee for Physics, said.
This newer understanding has the potential to bring forth new ideas for quantum computing and sharpen its tools for more complex problem-solving, data extraction, and processing. The world is already heavily reliant on semiconductors. To add to expectations, this discovery surely contributes to constructing more durable, accurate, and efficient models of future semiconductors.
The scientists involved in this groundbreaking research are also not confined to the shackles of academia, as two of the Nobel Laureates, Martinis and Devoret, were both involved in Google. Devoret is the current Chief of Google Quantum AI, and Martinis worked as the head of Google's Quantum Artificial Intelligence Lab until 2020.
At Google, Martinis was part of the research team who, in 2019, said they had achieved "quantum supremacy", in which a computer harnessing the properties of subatomic particles did a far better job of solving a problem than the world's most powerful supercomputer.
This is also the second straight year that scientists linked with Google have won the Nobel Prize in Physics, owing to the constantly diminishing gap between academia and industry, which could be a calling card for other fields, as innovation and research must go hand in hand to ensure progress.
