🌌 The 2025 Nobel Prize in Physics

 When Quantum Physics Became Visible on a Chip;

Every year, the Nobel Prize in Physics celebrates discoveries that reshape our understanding of the universe.This year (2025), the prize went to three scientists ; John Clarke, Michel H. Devoret, and John M. Martinis for proving that quantum mechanics, usually seen only in atoms and electrons, can also appear in an electric circuit you can hold in your hand.

⚡ What Did They Discover?

They discovered two amazing phenomena in an electric circuit:

1. Macroscopic quantum tunnelling, and

2. Energy quantisation

These discoveries showed that quantum physics isn’t limited to the microscopic world . it can appear in larger, engineered systems too.

🧩 What is quantum mechanics?

Quantum mechanics is the science that explains the behavior of tiny particles like electrons, atoms, and photons.

In this strange world:

- Particles can act like waves.

-  They can exist in two states at once (superposition).

-     They can tunnel through barriers instead of climbing over them.

-  And their energy is not continuous .it comes in quantized packets (like steps, not a smooth ramp).

In daily life, we don’t see these effects because large objects are made of trillions of particles, and their combined behavior looks smooth and classical.

🔍 The big question

Physicists have long wondered:

 “How big can something be and still behave according to quantum rules?”

Usually, quantum effects vanish when systems get larger.

But these three scientists proved that quantum mechanics doesn’t stop at atoms . it can also control an electric circuit.

⚙️ The special circuit ; Josephson Junction

They used a tiny superconducting circuit . A  special type of circuit that allows current to flow without any resistance when cooled to very low temperatures.

This circuit included a component called a Josephson junction:

Imagine two superconductors separated by a thin insulating layer.

Even though the layer is not conductive, pairs of electrons (called Cooper pairs) can tunnel through it because of quantum effects.

This forms the heart of many modern quantum devices.

You can think of it like a valley and a hill . In normal physics, a ball cannot roll over the hill without extra energy.

But in quantum physics, the ball can mysteriously tunnel through the hill and appear on the other side.

🧪 What they did in the lab

In the 1980s, Clarke, Devoret, and Martinis built and cooled such circuits close to absolute zero temperature.

They then observed two amazing things:

1. Macroscopic Quantum Tunnelling

The entire electric current in the circuit  made of billions of electrons  suddenly “escaped” through a barrier without climbing over it.

That’s like seeing a large crowd walk through a wall, not over it.

This was proof that quantum tunnelling can happen in a system visible to the naked eye.

2. Energy Quantisation

When they gently added energy to the circuit, it didn’t increase smoothly.

It only absorbed specific, discrete amounts  like steps on a ladder, not a continuous ramp.

This meant the circuit behaved like a giant atom with quantized energy levels.

🧠 Why this is important

This discovery showed that quantum behavior is not limited to microscopic particles.

It can be engineered and controlled in man-made systems.

Their work proved that:

Large electrical systems can have quantum energy levels.

The boundary between the quantum and classical worlds is not fixed . it depends on how well we isolate the system from noise and temperature.

🧰 : From discovery to technology

The experiments by Clarke, Devoret, and Martinis became the foundation of modern quantum technology.

Their circuits evolved into:

Superconducting qubits  the basic units of quantum computers.

Quantum sensors ultra-sensitive detectors used in medicine, astronomy, and materials research.

Quantum cryptography secure communication based on quantum rules.

Today’s quantum computers, like those developed by Google (Sycamore chip) and IBM, use the same kind of Josephson-junction circuits  direct descendants of the work done by these laureates in the 1980s.

💡  A simple analogy

Imagine a marble trapped in a bowl:

In classical physics, it can only escape if you shake the bowl hard enough (give it energy).

In quantum physics, it can disappear from one side and reappear outside the bowl  without enough energy to climb out.

Now, imagine not just one marble, but billions of them acting as one and doing the same thing.

That’s exactly what these scientists saw in their circuits.

They showed that quantum effects can be observed in a collective system made of many particles.

🌍  The legacy

Because of their pioneering experiments:

We can now design circuits that behave like artificial atoms.

Quantum computers can perform calculations impossible for classical computers.

Scientists can test where the “boundary” between the quantum and classical world truly lies.

Their work has bridged the invisible quantum world with the technology we can touch.

🏆  Why they truly deserve the Nobel Prize

John Clarke, Michel Devoret, and John Martinis didn’t just study theory .

they proved that quantum mechanics works at a human scale.

Their experiments helped transform an abstract mystery into practical technology.

Just as the invention of the transistor launched the digital era,

their work launched the quantum era.

✨ Final thought

The 2025 Nobel Prize reminds us that the universe’s deepest laws are not just hidden inside atoms 

they can be built, measured, and seen in action on a tiny chip.

It’s a beautiful message:

“Quantum physics isn’t just the world of the very small and it’s the foundation of everything.”