Schrödinger’s Cat: The Feline That Changed Physics

What if I told you that humankind has made a plethora of discoveries in the quantum world because some guy thought about killing a cat? Seems bizarre, doesn't it?

The Schrodinger cat experiment is a famous thought experiment that was formulated in 1935 by Erwin Schrodinger who was a world-famous Austrian-Irish theoretical physicist. Despite being just a convoluted idea, it has contributed to so many inventions in the field of science and quantum mechanics, including the internet. 

So what is this thought experiment? Well, Schrodinger surmised that if a cat is placed in a box with a mechanism to kill it, but with only a 50% chance that it'll be killed; the cat is both dead and alive at the same time. It's like a zombie apocalypse just more academic. Schrodinger’s thought experiment involved putting the cat in a bunker with poisonous gas, radioactive substances, or unstable gun powder that has a 50% chance of blowing up, so as long as the bunker was closed, the cat would be both dead and alive. Once the bunker/box was opened, one of the two states would come into reality. 

Imagine you order a package online, but as you’re tracking your package, it says that it's both arrived and lost at the same time. If you see it at your front door, it's arrived, whereas if you don’t, it's lost, and you probably have to call the company and complain.

Okay, so we understand the thought experiment, but why is it important? What is the point of putting a poor cat in the box? Well, the thought experiment is tied to an idea in quantum physics: how particles can be in two states at once until they are observed. Just as the cat was both dead and alive until the box was opened and one of the two realities came true as it was observed. This thought experiment was a macroscopic example of something that has been detected on a microscopic level: wave-particle duality.

So what is wave-particle duality? Have you ever tried to decide between two options, only to feel like you’re stuck in both at once? Like when you say you’re "on a diet" but also find yourself halfway through a pizza? Congratulations, you’ve just embodied wave-particle duality. It's truly one of the strangest ideas in quantum physics but also terribly mind boggling.

Wave-particle duality is the idea that tiny particles, like electrons and photons, can act both like particles and waves, depending on if they are being watched. It’s like they have stage fright!

If this sounds weird, don’t worry; quantum mechanics is basically built on weird. Just ask Schrödinger’s Cat, who (thanks to quantum uncertainty) exists in a state of being both alive and dead until you check up on it. It’s almost like the universe refuses to make up its mind until someone peeks. So, how do things exist as two different things at once? Is reality just one big indecisive mess? 

Wave-particle duality is a fundamental concept in quantum mechanics that states that particles (on a microscopic level), such as electrons and photons, can exhibit both wave-like and particle-like behavior depending on how they are observed. In some experiments, like the famous double-slit experiment, light and electrons create interference patterns, behaving like waves that spread out and overlap. However, when measured or detected directly, they appear as discrete particles, hitting specific points. This strange duality challenges our classical understanding of physics, where something is either a wave or a particle, but not both. But actually it can be both; it just depends on whether we are observing or not. Doesn't it just seem so out of the box? (pun intended)

Wave-particle duality is kind of like Spiderman, he is both Peter Parker and Spiderman until he puts on the spider suit and is perceived as Spiderman.

Let's take a look at perspective in the Schrodinger’s cat experiment. From our perspective, the cat is both dead and alive until we open the box, and when we do, the cat has a 50% chance of survival. So, if this experiment was performed enough times, half of the time the kitty survives, and half of the time, the kitty doesn't. But what about the cat’s perspective? There is a 50-50 chance for the cat to either see the gunpowder explode or not see it explode; this decides whether the cat lives or dies. So for the cat, its reality becomes entangled with the probability of the gunpowder exploding. And it’s our observation that forces one of the two perspectives into reality for the cat. But I think the real moral of the story is to not let any physicists pet-sit your cat.

Schrodinger crafted his cat scenario during the summer of 1935, in close dialogue with Albert Einstein. But why is this thought experiment evidently so violent? Well, there is actually a very elucidatory theory for that. Schrodinger came up with this thought experiment in the face of a looming world war, so it’s no coincidence that Schrödinger’s thoughts turned to poison, death, and destruction. Schrödinger’s cat should remind us of more than the beguiling strangeness of quantum mechanics, but that scientists are, like the rest of us, humans who feel and fear.

The theory started with the simple beginnings of Einstein and Schrodinger discussing a ball in a box and later emerged as the convoluted thought experiment it is today. Schrodinger is most famous for something he never even performed, it was simply a thought that led to so many discoveries and a new understanding of the quantum world.

So how is Schrodinger’s cat experiment related to modern technology? Schrödinger’s Cat is not just a weird thought experiment—it actually connects to modern technology, especially in quantum computing and quantum cryptography. At its core, Schrödinger’s Cat illustrates the concept of superposition, where a system exists in multiple states at once until it is measured. This idea is the foundation of quantum computing, where quantum bits (qubits) can be in a state of 0, 1, or both simultaneously. Unlike classical computers that process data in binary (either 0 or 1), quantum computers leverage superposition to perform complex calculations exponentially faster. Scientists are also developing a quantum internet, which would use quantum entanglement (another quantum effect related to Schrödinger’s Cat) to transfer data instantly across vast distances. This could lead to super-fast, ultra-secure global communication networks. Additionally, Schrödinger’s Cat is linked to quantum cryptography, where quantum states collapse when observed. This principle is used in quantum key distribution, ensuring that any attempt to intercept secure communications will alter the system, making eavesdropping impossible.

In a way, Schrödinger’s Cat isn't just a paradox—it’s helping shape the future of computing and cybersecurity!

There was this old joke that goes like ”the internet exists to share cat videos”, and on a very deep level, the internet does owe its existence to an imaginary cat because Schrödinger’s cat experiment is applied in the making of transistors. Millions of these transistors are put on a computer chip and power the device you are using to read this very article or even in fact to watch cat videos.

Ever had a moment where you weren’t sure if you passed a test until you actually checked the results? Well, congratulations—you’ve just lived through Schrödinger’s Cat, minus the feline drama!

~ Sara Kulkarni, Cosmox Blogs