Can All Particles of a Cat Be in Superposition Simultaneously?

[durant35]

That's not possible as I have explained. I have zero idea why you want to pursue it.

You need to study the actual theory - you will never understand it the way you are trying to.

Thanks
Bill

I don't want to pursue it, I want to get away from it, because it seems absurd. You said that theoretically the interference is not zero, that's why I'm asking.

 

[bhobba]

I don't want to pursue it, I want to get away from it, because it seems absurd. You said that theoretically the interference is not zero, that's why I'm asking.

Did you read what else I said about applied stuff? For the last time - there is no superposition of alive and dead. As far as I am concerned that's the end of the matter and I will not discuss it any further.

Thanks
Bill

 

[durant35]

I'm sorry Bill, I didn't want to be annoying or anything like that. Believe me I read every letter that you write and try to analyze it but so many questions pop from my head and some things that you say then sound inconsistent, like the theoretical existence of interference and absence of superposition of alive and dead.

 

[durant35]

And even reading some old posts on this forum implies even more confusion, for instance Nugatory said this:

"You have misunderstood the point of Schrodinger's thought experiment. There has never been any serious doubt that the cat is always either alive or dead (although we may not know which it is) with no funny 50% alive/50% dead states.

Schrodinger proposed the thought experiment to point out a problem with the 1920's vintage understanding of quantum mechanics - the formalism as it was then understood suggested that the cat could be in one of these funny states even though no one believed that it could be.

The resolution came with the discovery of quantum decoherence some decades later. The half-dead/half-alive state very rapidly evolves into a state in which the cat is either alive or dead - we may not know which, but it is one or the other as surely as a tossed coin is heads or tails but not some funny mixture of the two."e

Everything is fine until this sentence: The half-dead/half-alive state very rapidly evolves into a state in which the cat is either alive or dead. I understand the second part of the sentence but the first clearly implies that the half-dead and half-alive state exists. And you said that the cut is at the particle detector so the cat sets in a definite state long before opening the box.

 

[bhobba]

like the theoretical existence of interference and absence of superposition of alive and dead.

Your issue is you may read what is said but do not take it on board. For example you have had explained to you in another thread that some really small number like say 1/googleplex is the same as zero. It one of the basics of applied math used, often without explicitly starting it because its so obvious, to make sense of things. Then you turn around and start carrying on about some theoretical existence of interference. Any theoretical interference terms are zero because they are so small.

If you want to avoid confusion you must start thinking more clearly about this.

Thanks
Bill

 

[bhobba]

The half-dead/half-alive state very rapidly evolves into a state in which the cat is either alive or dead. I understand the second part of the sentence but the first clearly implies that the half-dead and half-alive state exists. And you said that the cut is at the particle detector so the cat sets in a definite state long before opening the box.

All that is saying is if you analyse it as an entangled system (ie the cat is entangled with the radioactive source) rather than the classical parts already decohered by the environment then that's what the analysis shows. But in reality the cat and everything in the box is decohered by the environment. This is the type of thing that's done in mathematical modelling all the time - we have slightly different models giving slightly different results. But again we have the 1/googleplex issue - the time is so small its zero.

Once and for all the cat is a macro object decohered into parts with definite position. An alive cat has a totally different arrangement of those parts than a dead cat. The alive cat has a beating heart - the dead cat doesn't. Things with definite position can not move and be still. They can never, ever, ever be in superposition.

Thanks
Bill

 

[durant35]

I've read a bit of the Where does the weirdness go and it's great, combined with your help it increases my understanding. Thanks.

The only barriere is the fact that Zurek and other authors mention decoherence time so often, like superpositions occur all the time and they get destroyed which isn't the same like the cat that is decohered since its birth and alive. What do they mean really? I'm sure you have insight.

 

[bhobba]

I'm sure you have insight.

No need to post here - you already posted it in another thread.

Thanks
Bill

 

[durant35]

No need to post here - you already posted it in another thread.

Thanks
Bill

I'm sorry, I accidentally posted it there without noticing that it's another thread. So basically Zurek and others are referring to the decoherence time as a reason for localization of the object and that it stops it from spreading. They aren't referring to the fact that we as humans enter some weird dead and alive state that gets destroyed in quick time. Right? So macro objects are decohered from the beginning, there is no coherence to begin with.

[QUOTE="bhobba, post: 5383592, member: 366323" But in reality the cat and everything in the box is decohered by the environment. This is the type of thing that's done in mathematical modelling all the time - we have slightly different models giving slightly different results. But again we have the 1/googleplex issue - the time is so small its zero.
Thanks
Bill[/QUOTE]

What do you exactly mean or on what did you refer when you mentioned this amount of time?

 

[bhobba]

So basically Zurek and others are referring to the decoherence time as a reason for localization of the object and that it stops it from spreading.

No - they have their own arguments that I am not into nor particularly interested in. You are on your own there. Start a thread on it.

I am explaining why decoherence time is still a consideration in what I am explaining to you that all macro objects are constantly decohered into an actual position and why it remains like that.

Thanks
Bill

 

[bhobba]

What do you exactly mean or on what did you refer when you mentioned this amount of time?

I thought I was explicit. You can resolve the Schroedinger's Cat paradox in a number of ways. One way is you consider the cat and nucleus as an entangled system. But its not as good a model as I have been discussing which is closer to what's going on - although it probably has some explanatory advantages. At all times the classical objects the cat, the detector, the table etc etc are classical because they are always interacting with the environment.

The time came from your concern, that has been addressed in a number of threads you participated in, that because the time or interference terms or whatever is theoretically not exactly zero. It was pointed out very very small quantities can be taken as zero. But even after that it worried you. Hopefully you now understand its a non issue. As I said in one of those threads some get caught up in it. If you do then I can't help you because the whole decoherence program falls to pieces and I will not be drawn into arguing it.

Thanks
Bill