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India Today
4 days ago
- Science
- India Today
Erwin Schrodinger, the man behind the famous cat experiment that questioned reality
A cat is in a sealed box. It is both alive and dead, at least until you open the the sealed chamber also sits a vial of vial could be triggered to break by a tiny amount of radioactive material that may (or may not) release energy and change form over time. Until you look, the cat exists in a strange twilight: both alive and is absurd, morbid, and yet -- utterly central to one of the most important debates in the box, Erwin Schrodinger was not looking for a pet rescue mission but making a point: in the strange realm of quantum mechanics, reality itself may be undecided until you was no cruel animal experiment in a lab. And Schrodinger never trapped a real cat. It was a thought experiment, dreamt up in 1935, in a Europe bracing for war and in a scientific community still grappling with the bizarre new rules of quantum image of Schrodinger's cat was so sharp, so unsettling, that it leapt from physics papers into cultural understand why a man would conjure such a morbid mental picture, you have to rewind to Vienna in the early 20th century. There lived a curious boy who would one day challenge how the universe itself is GIFTED CHILD TO WAVE MECHANICSErwin Schrodinger was born on August 12, 1887, in Vienna, the only child of a father who ran a small linoleum factory and a mother from an academic family. Their cultured, upper-middle-class home was filled with books, art, and scientific Erwin excelled early, mastering advanced mathematics while classmates were still wrestling with basics. The coffee-houses and lecture halls of the city fed his fascination with science and philosophy. 1927 Solvay Conference (Photo: Wikimedia Commons) Row 1: A. Piccard, E. Henriot, P. Ehrenfest, Ed. Herzen, Th. De Donder, E. Schrdinger, E. Verschaffelt, W. Pauli, W. Heisenberg, R.H. Fowler, L. Brillouin, Row 2: P. Debye, M. Knudsen, W.L. Bragg, H.A. Kramers, P.A.M. Dirac, A.H. Compton, L. de Broglie, M. Born, N. Bohr, Row 3: I. Langmuir, M. Planck, M. Curie, H.A. Lorentz, A. Einstein, P. Langevin, w:Charles-Eugne Guye, C.T.R. Wilson, O.W. Richardson He entered the University of Vienna in 1906, studying under the likes of Friedrich Hasenohrl, and earned his doctorate in 1910 (Maths History), before the world plunged into chaos with World War served in the Austrian army as an artillery officer in the war. Even on the front lines, he carried notebooks filled with equations. The war ended with Austria's empire in ruins, and Vienna became a place of scarcity but also intellectual BREAKTHROUGH THAT WON HIM THE NOBELBy the mid-1920s, quantum mechanics was in its chaotic infancy. Werner Heisenberg had proposed 'matrix mechanics', a powerful but abstract method to describe the strange behaviour of subatomic particles. But Schrodinger took a different 1926, while on a skiing holiday in the Swiss Alps resort of Arosa, he worked on the wave equation that would cement his place in history -- a mathematical description of how particles behaved not as fixed points, but as 'wave functions' spreading out in space and not only matched Heisenberg's results, but offered a more intuitive picture of the quantum world. It was the bridge that connected the strange predictions of quantum theory with experiments in the real wave mechanics explained phenomena like the hydrogen atom's energy levels with breath-taking accuracy, and won him the 1933 Nobel Prize in Physics, shared with Paul was this work, and not the cat, that made him a central architect of quantum theory. Schrodinger's Nobel Prize Diploma (Photo: Wikimedia Commons) advertisementPOLITICS, IDEOLOGY, AND EXILESchrodinger's life was tangled up with the politics of his time. The cat came later, in a world shadowed by Nazi politics were complex -- pacifist, humanist, and deeply opposed to totalitarianism. In 1933, as Hitler consolidated power, he resigned from his post in Berlin and left Germany, rejecting Nazi brief academic posts in England and Austria, he eventually took up a role at the newly founded Institute for Advanced Studies in Dublin, helping shape it into a hub for theoretical he introduced the cat in a paper in 1935, Europe was already edging towards another catastrophic THE CAT, A QUANTUM PARADOXBy that time, Schrodinger was struggling with a puzzling idea in quantum mechanics: under Niels Bohr's Copenhagen interpretation, a particle existed in a 'superposition' or multiple states at once until someone observed it. Particles chose the state when we looked at show how bizarre that sounded when applied to normal life, he cooked up his most famous mental image:Imagine a cat locked in a boxInside the box is a device containing a single unstable atom -- the kind that can randomly 'decay,' or change into something else, at an unpredictable momentIf the atom decays, it triggers a chain reaction: a detector notices the change, releases a hammer, breaks open a vial of poison, and the cat diesIf the atom does not decay, the cat livesQuantum physics says that until we actually open the box, that atom is in a sort of limbo -- both decayed and not if the atom is in both states, then the cat is, too: both dead and alive at the same time. Schrodinger's point wasn't that this scenario could actually happen to cats, but that the logic of quantum rules turns absurd when pulled out of the subatomic world and applied to everyday famous thought experiment was not meant to be solved; it was meant to unsettle. It was a challenge to scientists to question the Copenhagen interpretation, to probe its assumptions, and to think harder about what 'reality' really cat-in-a-box theory exposed the philosophical rift in quantum theory: Was reality determined only when observed, as the Copenhagen interpretation claimed, or was there some deeper, hidden truth?Schrodinger leaned towards the latter, uncomfortable with the idea that the universe only 'became real' when someone looked.A MIND THAT RANGED FAR BEYOND PHYSICSBeyond physics, Schrodinger strayed boldly into biology while in Ireland. His 1944 book What Is Life? suggested that the instructions for life or genetic information might be stored in a molecular 'code-script'.At the time, this was a leap of imagination, but it lit a spark in young scientists like James Watson, Francis Crick and Rosalind Franklin, who went on to reveal DNA's double helix, proving Schrodinger's hunch had been startlingly curiosity didn't stop with science. Schrodinger, though an atheist, immersed himself in Eastern philosophy, reading deeply in Vedanta and Buddhist thought. He was drawn to their ideas of unity and interconnectedness -- that the boundaries between observer and observed are an saw in these ideas parallels with quantum theory, and they quietly coloured his interpretation of quantum mechanics and his writings on the nature of reality. He also wrote on colour theory, and unified field theory. Shrodinger's signature (Photo: Wikimedia Commons) Even Schrodinger's personal life reflected his unconventional mind: while married, he also lived with a second partner -- a situation that baffled polite society but was tolerated in the academic circles he moved to Vienna in 1956 after years abroad, he continued working until his death in 1961. He was buried in the small Austrian village of Alpbach. On his tombstone, instead of a cat, there's an engraving of the wave equation that changed physics his name echoes not only in physics textbooks but in quantum computer labs, philosophical debates, and the pages of science that paradoxical cat -- imagined, never harmed -- still prowls the world's imagination, a reminder that reality may be stranger than we think, and never fully revealed until we observe.- Ends
Indian Express
13-05-2025
- Science
- Indian Express
The universe, the atom, and a cat both dead and alive: Understanding Quantum Mechanics
The transistors that power your smartphone, MRI scanners that detect tumours and blocked blood vessels of the heart, atomic clocks in the GPS that help cars and planes navigate — all work on a science that, for decades, left even the sharpest minds deeply uneasy. Its predictions seemed so bizarre that Albert Einstein, famously known for his love of scientific order, remarked: 'God does not play dice with the universe.' That science is quantum mechanics — the framework that governs the universe at its smallest scales. At the heart of quantum mechanics lies a radical shift in understanding: Matter and light, when examined at the microscopic level, behave both like particles and waves. Even more strangely, these particles exist in a superposition of all possible states until they are measured or observed. That's like saying reality settles into a definite state only when you observe it. Sounds exotic? Read on. By the dawn of the 20th century, classical physics was on a roll, seemingly explaining most of the phenomena we saw around us — heat, light, electricity, and motion. But on the sidelines, there were already cracks. The theories of classical physics did not seem to hold good at the atomic and subatomic level. Experiments on blackbody radiation revealed a fatal flaw: hot objects did not glow as predicted, especially at high frequencies. To fix this 'ultraviolet catastrophe,' Max Planck proposed that energy come in discrete packets, or quanta. With this simple assumption — each atom emitting or absorbing only whole multiples of a tiny energy unit — Planck's formula matched the data perfectly. This launched the quantum age. In the years that followed, while the Newton-Einstein model gave an understanding of the macroscopic Universe, other scientists were trying to explain the atom. In 1913, Niels Bohr used quanta to explain why atoms emit light only at certain colours: electrons circle the nucleus in specific orbits and jump between them by absorbing or emitting a quantum of light. Soon afterward, Louis de Broglie suggested that matter—like electrons—also behaves as a wave. Experiments confirmed that electrons can form interference patterns, yet still arrive as individual particles. Werner Heisenberg then showed that it is fundamentally impossible to know at the same time where exactly a subatomic particle is and how fast it is moving – the famous uncertainty principle. Erwin Schrödinger, in turn, described particles as evolving wavefunctions, giving only the probability of where a particle might be found. So clearly, light and matter both speak a dual language: sometimes wave, sometimes particle. But this strange new theory did not sit well with everyone. Albert Einstein firmly believed in an objective reality — one that exists independently of observation. Niels Bohr, however, argued that quantum mechanics fully described nature, even if it defied classical intuition. Their famous debates came to a head at the 1927 Solvay Conference, where the world's greatest physicists gathered to discuss the meaning of quantum mechanics. Einstein kept challenging quantum ideas with thought experiments; Bohr, always patient, parried them masterfully. That intellectual duel remains one of the most important scientific conversations of the 20th century. Two concepts of the unveiling quantum world especially spooked its critics: 📍superposition, that says a particle can exist in multiple states simultaneously until it is measured, and 📍entanglement, that says two linked particles act in tandem, instantly affecting each other's state, even if they are far apart. In 1935, Einstein, Boris Podolsky, and Nathan Rosen (EPR) argued that quantum mechanics was incomplete in describing physical reality. In response, Schrödinger proposed a now-celebrated thought experiment to show why it is absurd to apply the quantum world at the macro level. A cat is sealed in a box with a radioactive atom, a Geiger counter to detect the radioactivity and a vial of poison. If the atom decays, the Geiger counter triggers and breaks the vial, and the cat dies. Here, if the interpretation of quantum superposition were to be taken literally, the cat would be both alive and dead until we open the box and look. Schrödinger's cat became the most enduring image of how the classical world differs from the quantum world. What applies across the macroscopic universe does not apply to its smallest building blocks, and vice versa. The idea that quantum particles are governed by probabilistic rules was deeply unsettling for many physicists who believed nature must be deterministic and objective. To reconcile quantum predictions with the belief in an underlying, well-defined reality, some proposed hidden-variable theories, which proposed that particles in fact possess definite properties at all times, but these are governed by variables that are hidden from current experiments. Because these hidden variables could not be measured explicitly by experiments, the particles which obeyed these laws would appear to behave probabilistically. In 1964, John Bell devised a practical test. He showed that any local hidden-variable theory must satisfy certain statistical bounds — Bell's inequalities — whereas quantum mechanics predicts clear violations. Landmark experiments beginning in the 1970s measured entangled particles and found exactly those violations. The result was inescapable: no local, predetermined account can match quantum predictions. Nature truly is non-deterministic and non-local at the quantum level. From Planck's first quantum in 1900 to Bell's experiments in the 1980s, it took decades to accept a world where particles can be waves, outcomes are fundamentally probabilistic, and distant particles can remain mysteriously linked. Yet every test confirmed that quantum mechanics, strange as it is, gives the most accurate description of nature we have. Once settled, quantum mechanics became the foundation for the technologies we take for granted. Semiconductors rely on quantum energy levels to control electricity. Lasers exploit stimulated emission of photons. MRI scanners use quantum spin of atomic nuclei to create detailed images. Atomic clocks measure vibrations of electrons to keep time with incredible precision. The quantum revolution shows that moments of crisis, when experiments clash with established ideas, can lead to paradigm shifts that reshape our world. By embracing quanta, waves, uncertainty, and entanglement, we've unlocked technologies unimaginable to Planck, Bohr, and Einstein. As two more epic technologies — quantum computing and secure quantum communication — emerge, we continue to turn nature's strangeness to our advantage. The universe, in all its paradoxes, is also our greatest inspiration.
