It all started with a cat. A cat locked in a box, alive and dead at the same time, at least until someone decided to look. An absurd, almost ironic image, created to explain how much the quantum physics was distant from everyday experience. A hundred years later, however, that theoretical oddity has left the laboratories and has silently entered our homes, hospitals, smartphones, even supermarkets.
A century ago, quantum mechanics surprised the very scientists who had built it. Today it is the invisible basis of technologies we take for granted, such as lasers, microchips, secure communications and the most advanced computing systems. It is a revolution that makes no noise, but which has changed the world much more than we imagine.
When quantum physics was born as an incomprehensible theory
A new analysis published on reconstructs this long journey Science from Marlan Scullyprofessor at Texas A&M University and also affiliated with Princeton University. In his story, quantum physics stops being an abstract discipline and becomes a story made of brilliant intuitions, errors, ideas considered crazy and concrete applications that keep our technological society going today.
At the beginning of the twentieth century, quantum physics was born to answer an apparently simple question: how do the smallest particles of matter behave? The answers overturned every certainty. Energy did not flow continuously, particles did not follow predictable trajectories, reality seemed to take shape only when someone observed it. It is no coincidence that even its founding fathers struggled to accept the consequences.
When Erwin Schrödinger proposed the famous cat paradox in 1935, he wanted to show how disturbing quantum theory became if applied to the real world. A thought experiment, nothing more. Yet, precisely those very counterintuitive mechanisms are today the basis of quantum computers and quantum cryptography, which promises communications that are impossible to intercept.
Schrödinger’s work joined that of other pioneers such as Werner Heisenberg And Niels Bohrwho from different perspectives tried to give order to a world that seemed to reject any classical logic. From this often heated confrontation, a new vision of nature was born which over time will become increasingly solid and usable.
Invisible phenomena that regulate our daily lives today
One of the key concepts that has emerged in this century is quantum coherence, or the ability of particles such as atoms and photons to behave as a single system even at a distance. It is thanks to this property that lasers exist, a technology initially considered useless and which today we find everywhere, from medicine to large-scale retail trade.
The same coherence makes entanglement possible, that deep bond between particles that Albert Einstein he looked at it suspiciously, calling it “spooky action at a distance.” Today we know that without this phenomenon we would not be able to detect gravitational waves or build instruments capable of measuring the universe with unprecedented precision.
Quantum physics is no longer confined to theoretical research laboratories. It is entering biology, where it allows us to observe viruses and molecules on a nanometric scale, and in the study of complex systems such as the climate. By analyzing materials that behave quantumly, such as superfluid helium, researchers are finding new patterns for understanding turbulence, which could potentially impact weather forecasting and transportation safety.
Then there are even more radical applications, such as quantum motors, which call into question physical limits considered insurmountable. We are not faced with ready-made solutions for everyday use, but with clear signs of a discipline that continues to push the boundaries of what is possible.
A century later, quantum physics continues to ask us questions
According to Scully, the true paradox of quantum physics is that the more it works, the more it leaves open new questions. Can gravity be described with the same rules as other fundamental forces? Will quantum computers really change medicine and materials research? What will upcoming quantum technologies reveal about the universe?
At the beginning of the twentieth century it was thought that physics had reached the end of the line. Today we know that it was only the beginning. And perhaps this is precisely its most fascinating side: a theory born to explain the invisible continues to surprise us, while shaping our present in a discreet, profound and often imperceptible way.
