Schrödinger’s cat

Question

I don’t understand..
When we observe it, we can define it’s state right? But it was never in both states. It was only in one, we just didn’t know which one it is. It’s not like if I go back in time and open the box at a different time, that the outcome will be different. It is one of the 2 outcomes, we just don’t know which one until we look. And when we look we discover which one it was, it was never the 2 at the same time. This is what’s been bugging me. Can anyone help explain it? Or am I thinking about it wrong?

In: Physics

Answer 1

Trying to ELI5 as it’s a complicated thing.

In superposition particles can be in more than one state. For example, a qubit in quantum computing is both 1 and 0 at the same time.

It’s only when you measure it – observe it – that it will have a clear state: 1 or 0.

The thought experiment includes an atom that can decay at any point – send out a radioactive particle. But as long as you don’t measure it, it’s both decayed and not decayed. Moving further, it means the bottle with the poison is broken and not broken at the same time, and this the cat is alive and dead at the same time. Only when measuring- observing by opening the box, you force the atom to be in one of the two states, and thus also the bottle, and thus also the cat.

Since it sounds as nonsense – how could a cat be dead and alive at the same time, Schrödinger wanted to show the superposition thing was ridiculous.

Take the example of a die. It has a value between 1 and 6. As long as don’t look, all numbers have an equal chance to face up. When you look, the state will be one of those numbers. In QM, you’d say that before observing, the die _has all numbers facing up at the same time_, until you look which will cause it to have only one value. That’s obviously not true.

Fun fact: Einstein was the first to come up with a thought experiment to show it was nonsense to him. Instead of a cat, it was a barrel of gunpowder that was both exploded and not exploded at the time. But somehow the cat became famous, and not the gunpowder.