Nothing exists

[andyandy]

All sub-atomic particles are described through probability waves - which describe the likelyhood that they will be in any given position. In many circumstances, that probability drops to virtually zero outside of a small region - however according to QM each probability wave extends across all of space throughout the entire universe......

which means that any given sub-atomic particle described through such a probability wave has a non-zero probability of existing anywhere.

now would this not mean that we can not be mathematically certain about the existance of anything that's component parts are sub-atomic? Or would a carbon atom still exist as a carbon atom on earth even one of it's protons existed in the Andromeda galaxy? Or to extrapolate further, there is a non-zero chance of every sub-atomic component of that carbon atom existing elsewhere - so where would that carbon atom be said to exist?


nb. the thread title may not be very relevant really, but it's too late to change it.....

*Im currently reading Brian Greene's fabric of the cosmos, so there may be a few such questions coming up

 

[Dancing David]

Paging Epepke, paging Epepke.

This doesn't happen as much with the larger particles as it does with electrons.

 

[andyandy]

Paging Epepke, paging Epepke.

This doesn't happen as much with the larger particles as it does with electrons.

ok, i appreciate this may not happen as often with protons as with say electrons - but there's still a non-zero chance of any sub-atomic particle existing anywhere....so i don't see the relevance of this.....

 

[Stimpson J. Cat]

andyandy,

ok, i appreciate this may not happen as often with protons as with say electrons - but there's still a non-zero chance of any sub-atomic particle existing anywhere....so i don't see the relevance of your point.....

It's not really correct to say that it has a non-zero chance of existing anywhere. It has a non-zero chance of being observed anywhere. That said, when it is observed, the wave-function collapeses, and from that point on the distribution is now centered around wherever you observed it (adjusted by its motion, of course).

What this effectively means is that a proton in the carbon atom could jump somewhere very far away. In the astronomically unlikely case that this would happen, it would no longer be a carbon atom.


Dr. Stupid

 

[andyandy]

andyandy,


It's not really correct to say that it has a non-zero chance of existing anywhere. It has a non-zero chance of being observed anywhere. That said, when it is observed, the wave-function collapeses, and from that point on the distribution is now centered around wherever you observed it (adjusted by its motion, of course).

What this effectively means is that a proton in the carbon atom could jump somewhere very far away. In the astronomically unlikely case that this would happen, it would no longer be a carbon atom.


Dr. Stupid

could you expand on the first couple of sentences?

"It's not really correct to say that it has a non-zero chance of existing anywhere. It has a non-zero chance of being observed anywhere."

they seem contradictory......

thanks

 

[Correa Neto]

Since macroscopic objects are made of an incredibly high number of particles, and the odds of any given particle being "teleported" (for the lack of a better word that surely exists but I'm too lazy to remember now) are too low...

You can have an idea on why QM can not be used the way woos use them to "explain" their "phenomena".

 

[andyandy]

Since macroscopic objects are made of an incredibly high number of particles, and the odds of any given particle being "teleported" (for the lack of a better word that surely exists but I'm too lazy to remember now) are too low...

You can have an idea on why QM can not be used the way woos use them to "explain" their "phenomena".

sure, if the odds of a single sub-atomic particle existing (or being observed?) anywhere in the universe (outside its likely probability wave) are vanishingly small....then the odds of more than one sub-atomic particle from the same atom existing/being observed at a great distance away must be vanishingly vanishingly small

but when we get to the macroscopic level, wouldn't the QM stuff all fall apart anyway?

 

[Stir]

could you expand on the first couple of sentences?

"It's not really correct to say that it has a non-zero chance of existing anywhere. It has a non-zero chance of being observed anywhere."

they seem contradictory......

thanks

The problem with saying "it has a non-zero chance of existing anywhere" is that you can fall into precisely the trap you're in. It is not true that the particle is actually in some precise location (& that the probability wave describes the probability that it's actually here or there), but rather that it exists in all places at once as a probability wave. You must not think of an elementary particle as a tiny chunk of matter ... it's not remotely like that. It 'is' the probability wave, not a speck with an actual precise but unknown location.

And as to the'collapse' of the probability wave on being observed: there are other interpretations than the Copenhagen interpretation. And what you're working with after measurement and 'collapse' is an instantiation of measurement (arguably a different 'thing' than the particle/proabability wave).

Words like 'is' 'exist' and 'thing' become very hard to understand in this realm.

 

[andyandy]

The problem with saying "it has a non-zero chance of existing anywhere" is that you can fall into precisely the trap you're in. It is not true that the particle is actually in some precise location (& that the probability wave describes the probability that it's actually here or there), but rather that it exists in all places at once as a probability wave. You must not think of an elementary particle as a tiny chunk of matter ... it's not remotely like that. It 'is' the probability wave, not a speck with an actual precise but unknown location.

And as to the'collapse' of the probability wave on being observed: there are other interpretations than the Copenhagen interpretation. And what you're working with after measurement and 'collapse' is an instantiation of measurement (arguably a different 'thing' than the particle/proabability wave).

Words like 'is' 'exist' and 'thing' become very hard to understand in this realm.

ok thanks for that.....

is it thought that sub-atomic particles actually are probability waves (until observed), or that they are just described by them?

or is that another question that you shouldn't ask?

 

[Stir]

ok thanks for that.....

is it thought that sub-atomic particles actually are probability waves (until observed), or that they are just described by them?

or is that another question that you shouldn't ask?

I think 'actually are' is closer than 'described by' , but again, we're in very murky waters where conventional understanding of existence (of 'things' with 'attributes') is of very limited application

 

[Stimpson J. Cat]

andyandy,

could you expand on the first couple of sentences?

"It's not really correct to say that it has a non-zero chance of existing anywhere. It has a non-zero chance of being observed anywhere."

they seem contradictory......

They seem contradictory because you are thinking in terms of classical particles, which always have a well-defined position, and are spatially confined to some specific region.

That view just doesn't work in QM.

Please note that pretty much any attempt to explain anything about QM in layman terms ends up amounting to imprecise analogies to classical mechanics. As a result, on some level they all end up seeming contradictory, because QM simply doesn't follow the same rules that classical mechanics does.

As soon as you start talking about the particle as something which exists at some specific place, you are already no longer talking about QM. In QM, we have fields. These fields represent the probability of an event occuring at some place and time. These fields are quantized. The quanta of these fields are called "particles", but they are not particles in the classical sense. Under "ordinary" conditions, where we are dealing with complex systems consisting of astronomically huge numbers of "particles", classical mechanics and the conventional notion of a particle becomes a very good approximation. But when you are at the quantum level, the only way to accurately describe what is going on is with the actual mathematical model. In many cases analogies and metaphors can be used to give a rough idea of what is going on, but such descriptions will always fail when you investigate them closely enough.

is it thought that sub-atomic particles actually are probability waves (until observed), or that they are just described by them?

or is that another question that you shouldn't ask?

Strictly speaking, neither. The question is not really meaningful. The particles are not probability waves. They are quanta of the field. They are not, strictly speaking, described by the probability waves. What is described by the waves is the probability of a particular event occuring at some position and time. To say that the waves are describing the particles is to say that the wave is describing the fields which the particles are quanta of, which is not really meaningful, because the waves are themselves just properties of the field.

I think maybe the question you are trying to get at here is whether these fields just represent what is really there, or are what is really there. There are many different hypotheses about this issue. Unfortunately, at this point they are all metaphysical in nature, and therefore cannot be answered. Many people (myself included) would argue that they are not even meaningful. Really this is just a variation of the question of metaphysical realism. Do we observe what is real? Or are observations somehow representative of what is real? Again, I do not really consider such questions to be meaningful, but most people apperantly do. Either way, these are not questions which can be answered with science (or at all, for that matter).


Dr. Stupid

 

[andyandy]

andyandy,


They seem contradictory because you are thinking in terms of classical particles, which always have a well-defined position, and are spatially confined to some specific region.

That view just doesn't work in QM.

Please note that pretty much any attempt to explain anything about QM in layman terms ends up amounting to imprecise analogies to classical mechanics. As a result, on some level they all end up seeming contradictory, because QM simply doesn't follow the same rules that classical mechanics does.

Dr. Stupid

That's a great reply.....thanks....

are there any "middle ground" texts on QM? It all seems to be in the popular science form - ie. with all the maths taken out, or in the postgrad form ie. ridiculously complicated maths left in......

i've got a decent maths grounding up to kinda 1/2yr undergrad level and would be interested in learning more about the maths behind QM....even if only at a somewhat rudimentary level.....

 

[Stimpson J. Cat]

andyandy,

are there any "middle ground" texts on QM? It all seems to be in the popular science form - ie. with all the maths taken out, or in the postgrad form ie. ridiculously complicated maths left in......

i've got a decent maths grounding up to kinda 1/2yr undergrad level and would be interested in learning more about the maths behind QM....even if only at a somewhat rudimentary level.....

For basic introductory QM stuff, you really only need basic Calculus and Linear Algebra. The more advanced stuff requires Group Theory, but you really don't need to go that far.

Anyway, a minor in mathematics should be sufficient to understand any undergraduate text on QM, as long as you have some basic classical physics under your belt too.


Dr. Stupid

 

[jmercer]

Wait until you get to the end of the book, if you're confused now.

So... instead of "Nothing exists", we should be saying "Everything exists"?

 

[Soapy Sam]

Stimpy- brace yourself for a naive question.

If a particle is the quantum of a probability field and the particle in question is the traditional photon emitted by a headlight of a spacecraft travelling at relativistic velocity, does the light cone of the vessel not restrict areas of spacetime said photon is able to reach?
If the above makes any sense at all (an assumption with a probability field of it's own), does this not imply that the probability of the photon being observed at some places is and always will be zero and that the field must be asymmetric and finite?

 

[Zombified]

If you bring up relativity, you're bringing up field theory.

First thing is, yes, the locality requirements of special relativity must be met by observable particles.

Second thing is, any uncertainty in knowing where a particle started from implies uncertainty in knowing its allowed to end up. So if the original particle could have been anywhere (with an appropriately small probability in some places), so can its final state (though in most places again with a small probability).

 

[Soapy Sam]

Even if the spaceship was diving through the event horizon of a black hole?

 

[Correa Neto]

Wait until you get to the end of the book, if you're confused now.

So... instead of "Nothing exists", we should be saying "Everything exists"?

Well, if one subscribes to the infinite multiverse idea, then everything that is possible, regardless on how small are the odds, will happen or exist (or happened, will happen, existed, will exist)...

At countless Universes, right now I am at my yatch, and there's that beautifull hot woman by my side...

 

[jmercer]

Well, if one subscribes to the infinite multiverse idea, then everything that is possible, regardless on how small are the odds, will happen or exist (or happened, will happen, existed, will exist)...

At countless Universes, right now I am at my yatch, and there's that beautifull hot woman by my side...

Oh, dear. Let's see. If the infinite multiverse idea is true, then it follows that anything that can exist, must exist somewhere, somewhen in some universe. And since there's no reason that I'm aware of that Gods cannot exist (as opposed to "do not")...

 

[CENOBITE]

I'm not a calculus major... nor even good at math in general. However some good books to read for the regular joe would be the hit book "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory" and "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" both written by Brian Greene. There is also a PBS show based on them.