Last fall, I got a shirt from Amazon that I liked: Amazon commercial.
It had this on the front:Explaining the Joke
It turns out that a friend of mine had never heard of Schrödinger’s cat so I tried to explain it to her. I did a crappy job so I’m gonna try again.
Note: I looked this up in Schrödinger’s cat on Wikipedia to make sure that I was on the right track. If I’m horribly inaccurate, just assume that I read it wrong.
In quantum physics, they spend a lot of time not knowing what is going on. Subatomic particles have attributes that seem contradictory when we compare these attributes to objects that we can see.
One example of this is with light. Light is made up of photons. These are particles. And waves. That doesn’t make any sense if you’re trying to compare photons to objects that we’re familiar with like billiard balls and waves on the ocean.
On a quantum level, particles are often described as a statistical event rather than a solid billiard ball. They exist in all possible states until they interact with something else. Once this interaction happens, then they start acting like billiard balls.
Until the interaction, the particle existed as a cloud of possible positions, states, and directions. After the interaction, the cloud of other possibilities collapsed into a particle with one position, state, and direction.
When the particle is in its cloud state, it’s said that all of the possible positions, states, and directions are “superpositioned” over each other.
Schrödinger was discussing with Einstein how absurd superpositioning would be at the level that we can see. He suggested a thought experiment where a cat was put in a box with a device that would poison the cat if a particle decayed in a certain way. Since the cat’s life depended on the superpositional state of the particle, then the cat would also be in a superpositional state. All possible states of the cat would be superpositioned, both alive and not alive, until the particle interacted with something else.
Sucking the life out of the joke
A lot of folks think that the cat will continue in this superpositioned state until someone opens the box and looks at the cat. This is because physicists talk about the particle being “observed”. This is why I’ve been talking about interactions instead of observations. In this case, an observation is any test that will establish the state of the particle. The observation happens when the device tests whether the particle has decayed.
If the cat ever existed in a superpostional state, it was between the time that the cat and the device were placed in the box and the time that the device made its first test of the particle.
The joke is ruined. My work is done.