I don't understand the principle of Schrodinger's Cat

Quotidian · Post by **Quotidian** » September 20th, 2013, 5:52 pm

"Because wer're talking about complex numbers and not real numbers, the information entropy is no longer restricted to the range 0 and 1'."

Well, good luck with that. It is an hour-long lecture with a lot of advanced math. And for every opinion on the 'philosophical implications of QM', you can find a dissenting opinion from another physicist.

There are thousands of books out there on the implications of QM, some of which are fringe, some not, some support scientific realism, many don't. One that I have recently come across is Uncertainty: Einstein, Heisenberg, Bohr, and the Struggle for the Soul of Science by David Lindley, who is a physicist and science writer, and which, from what I have read, provides a very good account of the philosophical conundrums of quantum mechanics. The other thing which is nice about this book is its historical approach and the discussion of the debates between the various personalities involved.

Teralek · Post by **Teralek** » September 20th, 2013, 6:11 pm

Quotidian wrote:"Because wer're talking about complex numbers and not real numbers, the information entropy is no longer restricted to the range 0 and 1'."

Well, good luck with that. It is an hour-long lecture with a lot of advanced math. And for every opinion on the 'philosophical implications of QM', you can find a dissenting opinion from another physicist.

Yeah... I know... I just happen to agree with this solution. It's the one that makes more sense to me. But it's still a mystery nonetheless.

Dolphin42 · Post by **Dolphin42** » September 23rd, 2013, 4:37 pm

It is an hour-long lecture with a lot of advanced math.

Aha. I was talking to an Australian yesterday and meant to ask her whether Australians say "math" (like US) or "maths" (like UK) but forgot. Now I know. Thank you Quotidian! (You're Australian, right?)

Oh and Schrodinger's Cat. Something to do with quantum macrostates? I don't know. I did a degree in physics but have mostly forgotten it.

Geordie Ross · Post by **Geordie Ross** » September 23rd, 2013, 4:42 pm

Dolphin42 wrote: (Nested quote removed.)

Aha. I was talking to an Australian yesterday and meant to ask her whether Australians say "math" (like US) or "maths" (like UK) but forgot. Now I know. Thank you Quotidian! (You're Australian, right?)

Oh and Schrodinger's Cat. Something to do with quantum macrostates? I don't know. I did a degree in physics but have mostly forgotten it.

When I was at school it was usually referred to as torture, not math or maths, (from Newcastle)

Schrödinger's cat is for superposition, all possible states/positions at the same time until observed which collapses the wave function.

Dolphin42 · Post by **Dolphin42** » September 23rd, 2013, 4:49 pm

Why aye man!

Geordie Ross · Post by **Geordie Ross** » September 23rd, 2013, 4:58 pm

Slight faux pas, its "wey" not "why". Uncultured Philistine.

Dolphin42 · Post by **Dolphin42** » September 23rd, 2013, 5:05 pm

Is it? Ah. Sorry. I'm an ignorant southerner.

Anyway, probably best leave it there, as the connection between a discussion about Schrodinger's Cat and the Geordie vernacular is probably tenuous at best.

Geordie Ross · Post by **Geordie Ross** » September 23rd, 2013, 5:10 pm

Although, it is both 'wey' and 'why' aye until a Geordie observes it, which collapses the wave function and it becomes one of the two.

I'm sorry, I couldn't help myself.

Dolphin42 · Post by **Dolphin42** » September 23rd, 2013, 5:15 pm

Nice one. Connection made.

Geordie Ross · Post by **Geordie Ross** » September 23rd, 2013, 5:28 pm

Nailed it

Quotidian · Post by **Quotidian** » September 23rd, 2013, 7:03 pm

Dolphin42 wrote: (Nested quote removed.)

Aha. I was talking to an Australian yesterday and meant to ask her whether Australians say "math" (like US) or "maths" (like UK) but forgot. Now I know. Thank you Quotidian! (You're Australian, right?)

Oh and Schrodinger's Cat. Something to do with quantum macrostates? I don't know. I did a degree in physics but have mostly forgotten it.

Well it was always "maths" in Australia, but I have picked up 'math' from conversing with Americans....not that there's much in it.

Mrs Schrodinger: 'Erwin! What have you done to the cat! It looks half dead!'

Xris · Post by **Xris** » September 24th, 2013, 3:58 am

I have reported them to animal welfare.I suppose if we did not look it could live forever.

Buzz · Post by **Buzz** » July 6th, 2015, 1:34 pm

On the Physics Forum, Quantun Physics sub-forum, there is a recently closed) thread "is the cat alive, dead, both or unknown". There has been a long discussion there about the cat, both physical and philosophical. It was recently ended when a forum mentor, after being very patient for quite a while, finally decided that the disccusion had become too philosophical for that forum, which has a premise: "philosophy is not discussed here".

I think that some of the readers here who have an interest in the philosophy of quantum mechanics might find thiu thread both entertaining and educational.

Graeme M · Post by **Graeme M** » July 20th, 2015, 11:04 pm

Thanks for the tip, I'll have to drop by there and have a read. I always find these discussions intriguing and challenging - although mostly well over my head. I don't know anything about wave functions and the like, nor really of quantum mechanics.

I've read a couple of pages of this thread, and don't 'get' the Schroedinger's Cat paradox. As I often observe, I am much too pragmatic for some of these things and I tend to simplify things too much I guess.

My take is this. In the case of the cat, it is what it is. It is never in some nebulous all possible states superposition. What's in question is the state of the brain of a human observer.

The brain of an observer who cannot see into the box will be in some state of flux. One or more models may be formed and theories proposed, but a model and its theory is not validated until some measurement is taken. That does not inform the cat/box system, it simply informs the model and theory. Or put another way, the state of the brain observing the situation is not settled into a particular state until the measurement is performed.

The cat is what it is. The brain's representation of that state cannot be settled until the observation happens. What is the paradox?