Register to reply

Quantum superpostion, determinability, and existance of virtual particles

Share this thread:
Supaiku
#1
Jan4-06, 12:19 PM
P: 29
I thought this up as a result of a philosophical debate over existance and more specifically creation. I asked them to give an example of creation saying that what we usually see as creation/destruction is only change, a restructuring. (ie. table being destroyed is actually a release of energy and redistribution of mass).
Someone said "Virtual Particles!"
So I'm wondering if they exist.

In trying to find out by myself I think it's true that we honestly don't know. They are either tools we have for describing reality, or actual varible particles.


Something I stumbled on was quantum superpostion. ie. quantum wave interference.
I wonder, if you could (hypothetically) calculate the interference for the entire universe as one thing what would you get? In other words calculate the interference of the waves in a quantum echancial system that is the entire universe (all things).
I bet it's a line and results in a determinable universe! Problem is we can't do that.
What do you think?
To me it makes sense that if you expect to retain absolute determinability you have to have absolute knowledge. We don't notice it so much on large scale classic mechanics because the error is so small, but quantum mechanics is so small that the error is massive (to the point of indeterminability) if you lack complete information. Perhaps if we could compute the quantum superpostion for a a whole classic system as it would appear in quantum mechanics it would render a similar level of accuracy to the classical counterpart. We can't even do that.
eh? eh?
Phys.Org News Partner Physics news on Phys.org
Physical constant is constant even in strong gravitational fields
Physicists provide new insights into the world of quantum materials
Nuclear spins control current in plastic LED: Step toward quantum computing, spintronic memory, better displays
ZapperZ
#2
Jan4-06, 12:35 PM
Emeritus
Sci Advisor
PF Gold
ZapperZ's Avatar
P: 29,243
It is a bad sign when you say you "stumble" upon things, especially quantum superposition. It implies that you really didn't understand it, but rather gained only a superficial idea of what it is. It is very dangerous to use that and think that you can use it to extrapolate into other things, something that is often done in philosophy.

If that is what you wish to do, then this thread will end up in the Philosophy forum. However, if it is the PHYSICS that you are interested in, then you will need something more substantial before diving into a the question of "quantum superposition for a whole classic system", much less the universe (whatever that is).

Zz.
Supaiku
#3
Jan4-06, 02:33 PM
P: 29
Quote Quote by ZapperZ
It is a bad sign when you say you "stumble" upon things, especially quantum superposition. It implies that you really didn't understand it, but rather gained only a superficial idea of what it is. It is very dangerous to use that and think that you can use it to extrapolate into other things, something that is often done in philosophy.
If that is what you wish to do, then this thread will end up in the Philosophy forum. However, if it is the PHYSICS that you are interested in, then you will need something more substantial before diving into a the question of "quantum superposition for a whole classic system", much less the universe (whatever that is).
Zz.
Hence the asking... Anyways I don't appreciate math much so if it stays philosophical all the better, it came up in a philosophical context anyways, no problem if it stays there. Did what I say make sense? I asked in the quantum physics section (rather than philosophy) because I want someone who knows what they're talking about to tell me if I completly misunderstand (and hopefully why) or not.
And it ain't so dangerous. I'll just look a fool, no biggie. It's not like I'm gonna go trying to calculate a flying machine that uses quantum superpostion computations of a semi-complete classic system and go testing it off a cliff or anything.
If you don't wanna humor me that much could you at least tell me if I got the Virtual Particle thing right. Do they qualify positivly (or only possibly if that's the case) as "existing" and does their coming in and out of existance count as "creation" and "destruction"? Is the indecision surrounding the philosophical consequences of quantum physics on the whole the answer to this question? (ie. Copenhagan interpertation vs all that jazz Einstien thought vs multiple universes... like Wikipedia says in the quantum mechanics article)

ZapperZ
#4
Jan4-06, 02:48 PM
Emeritus
Sci Advisor
PF Gold
ZapperZ's Avatar
P: 29,243
Quantum superpostion, determinability, and existance of virtual particles

Quote Quote by Supaiku
Hence the asking... Anyways I don't appreciate math much so if it stays philosophical all the better, it came up in a philosophical context anyways, no problem if it stays there. Did what I say make sense? I asked in the quantum physics section (rather than philosophy) because I want someone who knows what they're talking about to tell me if I completly misunderstand (and hopefully why) or not.
And it ain't so dangerous. I'll just look a fool, no biggie. It's not like I'm gonna go trying to calculate a flying machine that uses quantum superpostion computations of a semi-complete classic system and go testing it off a cliff or anything.
If you don't wanna humor me that much could you at least tell me if I got the Virtual Particle thing right. Do they qualify positivly (or only possibly if that's the case) as "existing" and does their coming in and out of existance count as "creation" and "destruction"? Is the indecision surrounding the philosophical consequences of quantum physics on the whole the answer to this question? (ie. Copenhagan interpertation vs all that jazz Einstien thought vs multiple universes... like Wikipedia says in the quantum mechanics article)
I can't quite follow exactly what you understood with what you mean by "quantum superposition", so I cannot comment on whether it is correct or not.

Virtual particles are "real" as far as physics is concerned. You can calculate their interactions and how they affect the dynamics of the system. This may not satisfy the notion of "reality" for every field of study, but in physics, as long as they make their presence known, be it directly or indirectly, then they're relevant and ignoring such interactions will not give you an accurate answer in many instances. That is as far as it goes. When philosophy tries to take from that and run away with it, that's when several level of absurdities kick in.

At the risk of sounding tacky, I wrote a lengthy article on why QM is so difficult to comprehend. This will tell you why, without understanding the mathematics, QM appears disconnected to what we already know of our classical world. You may find the article either in my journal, or in the Physics Post website. This may give you insight on why, when you "don't appreciate math much", trying to reason through something like this, even for philosophical reasons, may end up being a futile exercise.

Zz.
samalkhaiat
#5
Jan4-06, 05:17 PM
Sci Advisor
P: 926
[QUOTE=ZapperZ]
they make their presence known,
Well done ZapperZ,
I love this sentence as much as I hate the often used phrase "calculation tools".
It makes its presence known. Yes, this is, I believe, the definition of any objective entity,Coffee table, Cucumber and virtual particles.
After all, virtual particles play an essential part in giving the cucumber its cucumber entity.
We should not think that nature does worry about what we can or cann't experience.

Happy new year

sam
Supaiku
#6
Jan4-06, 10:54 PM
P: 29
This is what I meant by quantum superposition. With that do I make any sense? (Where might I be misunderstanding?)

Is it your stance that science should not be extended past sciences then?

I have a few things about your article too. In it you say "The notes are not the important object. Rather, it is the sound that it represents that's the main point. The musical notes are simply a means to convey that point clearly and unambiguously." This brings me back to, at least a part of, what I'm trying to get at in my philosophical arguement: Are we sure that Virtual particles are real things or are they just ideas we've cooked up that work for the most part?

Also, how would you explain the coming into and exiting of virtual particles into existance? Do we know why they are so transient? Does a force create and destroy them? This is perhaps the most important of all the questions I have.


On a completly differnt note (back to your article though), I was listening to a portion of Feynman's QM lectures today and he mentioned pretty much the same thing you did... there's no way to experience quantum mechanics so, compared to classical mechanics it's entirely abstract and awkward - short of using math, he asserted that there's no grounding for it. Do you think showing kids lots and lots of computer models of quantum physics working (bother experiments that display it's effects and atomic level simulations) might allow kids to grasp the concepts easier and without math so that they could later learn and apply the mathematics easier? How possible is graphical modeling of QM?
I wonder how much you'd have to watch it to have it make as much stuff as the mundane classical mechanics:p
masudr
#7
Jan5-06, 01:01 AM
P: 932
Quote Quote by Supaiku
Do we know why they are so transient? Does a force create and destroy them? This is perhaps the most important of all the questions I have.
We know why they are so transient -- they must obey the time-energy uncertaintly relation. No "force" creates them; they are fluctuations of the electromagnetic field.

Do you think showing kids lots and lots of computer models of quantum physics working (bother experiments that display it's effects and atomic level simulations) might allow kids to grasp the concepts easier and without math so that they could later learn and apply the mathematics easier? How possible is graphical modeling of QM?
I personally find that many "atomic level diagrams" do not convey in any way at all the full formalism of quantum mechanics (and are also quite patronising). I experienced lots of these models, and lots of pop science books, which tried to describe the quantum world as "fuzzy" and "indeterminate." Having now studied QM to undergraduate level, I find that all of these explanations were entirely inadequate, and they failed to convey even some of the most basic ideas.

As ZapperZ points out, the only language we know of that can convey the ideas of Quantum Mechanics is mathematics; all other languages have ambiguities and this is what leads to the various interpretations of quantum mechanics.
ZapperZ
#8
Jan5-06, 05:29 AM
Emeritus
Sci Advisor
PF Gold
ZapperZ's Avatar
P: 29,243
Quote Quote by Supaiku
This is what I meant by quantum superposition. With that do I make any sense? (Where might I be misunderstanding?)
My stance on Wikipedia is well-known. I'm not going to comment on it.

Is it your stance that science should not be extended past sciences then?
If you reread what you just said here, you'll realize that you've answered your own question. If you extend science beyond science, it is no longer science, is it not?

I have a few things about your article too. In it you say "The notes are not the important object. Rather, it is the sound that it represents that's the main point. The musical notes are simply a means to convey that point clearly and unambiguously." This brings me back to, at least a part of, what I'm trying to get at in my philosophical arguement: Are we sure that Virtual particles are real things or are they just ideas we've cooked up that work for the most part?

Also, how would you explain the coming into and exiting of virtual particles into existance? Do we know why they are so transient? Does a force create and destroy them? This is perhaps the most important of all the questions I have.
We can cook up anything we like, but Nature doesn't care. If it doesn't work, it doesn't work. But in this case, it works!

The problem here is that you are STARTING with the concept of virtual particles, whereas if you really study physics (and not just study ABOUT physics), you'll realize that such a concept is a CONSEQUENCE of QM. So without fully understanding QM, you'll think that it is something that was made up out of thin air with no fundamental basis, which is the impression you seem to be having here. Many of what most laymen understand as QM are actually consequences of the formulation (uncertainty principle, "duality", etc..). These are the logical outcome of the formulation, what the animal left behind. They are not the animals themselves.

Zz.
Supaiku
#9
Jan5-06, 11:22 AM
P: 29
EDIT:
Actually, let me just restate the whole issue without wikipedia (though I'm still curious about what you think of it) and quantum superpositioning. I won't even have to know how any of it works, at least I don't think I will.
If we could take the position of every thing in the universe at the same instant could we then predict were they would go from there using quantum mechnics provided we had the computing power? How about what they did before we had their collective positions?


Register to reply

Related Discussions
Are virtual particles really there? Quantum Physics 250
Why forces are modeled as virtual particles in quantum mechanics? Quantum Physics 1
Virtual Particles High Energy, Nuclear, Particle Physics 10
Quantum Foam and Virtual Particles Quantum Physics 11
Virtual particles General Physics 9