# QM and GOD - and also what is

Hi,

this is my second post, so I start with a warm hello to all.

the world of the Quantum, is indeed "random" (or maybe is largely random) - but does this in itself argue or rid the existence of a theistic God?

My second question is even more suited to this forum, can anyone explain to me what is Hamiltian space, and just what is an "inner product"??

Thanks!

Ps: Please note I am dyslexic.

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QM says nothing about any gods, your our anyone else's. Discussion of God and <your topic here> should be put on the religion board.

Instead of Hamilton space, I think you mean Hilbert space. This is an "algebra" (the simplest one is the complex numbers), and an algebra is by definition a vector space with with a product that distributes.

So a vector space is a collection of things called vectors that you can add a + b = c and multiply by constanst ka = b so that it's linear k(a + b) = ka + kb.

And the inner product of two vectors gives a constant {b]ab[/b] = k.

In addition to the inner product we have the algebra product where the product of the two vectors gives another vector: a*b = v.

In quantum mechanics the states of a quantum system are in one to one correspondence with vectors (actually rays of vectors) in some Hilbert space. And observable properties are Hermitian operators from the Hilbert space to itself. I'll define Hermitian some other time.

re

“QM says nothing about any gods, you’re our anyone else's. Discussion of God and <your topic here> should be put on the religion board.”

I never claimed that QM does, nor am I discussing the existence of God, rather does the randomness that the QM, hold that the concept of theistic God, is thrown out of the window? I am not asking for a theological debate of Gods existence or no existence!

Thus issues such has
And just what does this randomness or random entail? – Would be an excellent start.
And of primary focus, e.g. is the universe thus RANDOM, or is it random from OUR perspective?

Secondly, while I do agree that for the most part, this part of my question could be better suited in the religion board.

BUT I also feel the issue will be and should be very accurate (and more so on the scientific parts. that is QM. Has God existence or nonexistence can not really be answered scientifically, it is clear that the discussion was not geared to “) within here “QM says nothing about any gods, your our anyone else's”. Rather we are dealing with this random issue…. And from that we can make some “answers”

Now for my second part of my post:

“Instead of Hamilton space, I think you mean Hilbert space”

Indeed, my error – I apologize.

“and an algebra is by definition a vector space with with a product that distributes.”

Sorry I am not mathematical so please use layman terms – or more layman style.

I take this to mean – if I am incorrect please correct it – has a vector can be defined as - to me means direction of some sort, if we had lots or points linked up, they in turn will generate an“object”???

“So a vector space is a collection of things called vectors that you can add a + b = c

Like a straight line?

“and multiply by constanst ka = b so that it's linear k(a + b) = ka + kb.”

Sorry, but my background is not mathematical, from what I can have a very very crude guess and highly probably wrong: you incorporating the constant into the vector?

Is Ka = b the same a and b’s has in a+b=c?

Anyway can you please explain this!

What does K mean? – you do say…

And the inner product of two vectors gives a constant {b]ab[/b] = k.

But that is utterly worthless to me! To me your saying that K is the constant generated by the inner products of two vectors, yet there is no explanation has to what they really are!…. Which I am assuming by guesswork, an inner product is when you bring the constant together with the vector space? – like a “meeting place”???

chroot
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QM is a scientific theory. Quantum mechanics textbooks do not include the word God, nor do students studying the theory ever hear the word God mentioned in class. Quantum mechanics has nothing to do with God (though I suppose if God exists, then he has something to do with quantum mechanics ).

This is not really the place to begin learning the theory -- at least not with the formalism in selfAdjoint's post. If you'd like to learn it, I suggest you purchase a book.

You're not likely to get an argument about God going here on physicsforums, as we do not allow religious discussion here. If this thread wanders off into theological debate, it will be locked.

- Warren

chroot
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Originally posted by agnostictheist

But that is utterly worthless to me! To me your saying that K is the constant generated by the inner products of two vectors, yet there is no explanation has to what they really are!…. Which I am assuming by guesswork, an inner product is when you bring the constant together with the vector space? – like a “meeting place”???
Consider a concrete example. In Euclidean three-space ($\mathbb{R}^3$), the inner product of two vectors $a_1 \mathbf{i} + a_2 \mathbf{j} + a_3 \mathbf {k}$ and $b_1 \mathbf{i} + b_2 \mathbf{j} + b_3 \mathbf {k}$ is $a_1 \cdot b_1 + a_2 \cdot b_2 + a_3 \cdot b_3$.

In general, the inner product is simply an operation on two vectors that produces a scalar. In other words, the inner product is a map $[\cdot , \cdot] \mapsto \mathbb{R}$.

- Warren

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I didn't introduce the method of doing the inner product because it requires defining basis vectors, just as I didn't define Hermitian because it requires the involution. If you just want to have images in your head when you see the words, this level is OK, but you seem to actually want to do things with the concepts. That requires learning the math. Try the introduction to Linear Algebra down in the math sectioon of PF. That has some links you can use too.

re

Hello warren

Originally posted by chroot
QM is a scientific theory. Quantum mechanics textbooks do not include the word God, nor do students studying the theory ever hear the word God mentioned in class. Quantum mechanics has nothing to do with God (though I suppose if God exists, then he has something to do with quantum mechanics ).

No your wrong (on some points), those I am actually going to play too much of an advantage here, frist off: QM textbooks have/do mentioned "God", and some dissuss it. but to be fair I think you find, what your trying to say that the existence of God, or not - is not something that is taken has issue with QM! (there is a difference to what you are actually saying, and probably meaning - those you do state this elsewere)

You are correct that QM is a scientific theory, and has been "battle tested", but the issue i have already stressed is that is QM really fully random,or is it randomness? what might the source of this random[ness] be? and how from that might that relate to God - which ok is philosophical- or a Godly prespective (and that by the way doesnt mean thus a God must exist!, but in the same way has disscussing a singlarity, and external to this singlarty thus God is a nescessity!

This is not really the place to begin learning the theory -- at least not with the formalism in selfAdjoint's post. If you'd like to learn it, I suggest you purchase a book.
and what make you so sure, I have not already, or that this thread is meant for that intent?

I in essence asked for a debate, or arguments of what this "random" entails, and then how this might relate to a concept of God - while the second bit is philosophical, i made it an important point that i was intrested in the random part (which is scienfic )

in the intrests of being more lucid, let me re-phase the question, In QM "Random" - is a key component, even more importantly QM seems to be tired up with "reality", when we mean random in a sicenfic frame work we mean "unpredictble" - but to some extent, it does not mean for certain a lack of causation", rather a lack of measuring it... its a kind of semi-ignorance thing? for example HUP : states that, there is no way of accurately pinpointing the exact position of a sub-atomic particle, unless you are willing to be quite uncertain about its momentum, also there is no way of pinpointing the particles exact momentum, unless you want to be uncert about its postion!! - thus to measure both accurate at the same time is impossible (in fact EPR - also validates QM)

the result is a break down of determinism, in which we need to know the above.

- also note, that "things" (eg: electrons have a wave/particle duality. -

but does this mean the universe is fundermentally random?

while my maths is bloody awful i recall (from my undergrad days) that determinsic systems can yeild "random" (chaotic systems are fundermentally deterministic, BUT chaotic systems can bring about the illusion of X being Random!) - outcomes, and likewise random systems can yeild determinsic systems??

so maybe the universe had an "origin" that was fundermentally determinstic - no does not have to be God -

my other point is that has QM says that the oberver is very much apart of the system "he" obesvers (form a theistic veiw, god need not need to obervse to know, and science is a persuit for knowelege , FACTS, not nesscerly truth, so this is not a problem for theists!, but theists can not assert gods existence!)

and so "random" events might be assocated to degrees of freedom, one of which could be how we interact with our obervastion - maybe this makes some kind of blind spot??

on the EPR paradox, we are making on assumption, that i rarely see addressed, while atomic systems can NOT be seperated, and there is NO such thing has say an isolated electron, the space in which we measure say one photon, with detector A and one at detector B... further along (with anther photon)... do we assume that the space-time, is in the prespective OF OUR SPACE, the large - BUT the photon, might be using its prespective, in which case: this experiment is meangless to it? - "space-time" is not smooth, to it - while to us it is.?????

the upshot of this - assuming I am right here? - is that we are not measuring a quantum reality, we are in fact measuring, things as they appear in the context of a classically described apparatus! (Quantum phenomena!) the problems arise, when applying classical thought to this!

- I hope you can now see, why I beleive we should get the science right, even If what I am saying is wrong! -

re

ops sorry didnt mean to send it twice!

Last edited:
chroot
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Originally posted by agnostictheist
and what make you so sure, I have not already, or that this thread is meant for that intent?
If you don't know what an inner product is, you obviously don't know quantum mechanics. If you are not willing to learn quantum mechanics, then there is little point in discussing anything about it with you. You must learn a subject before you can be competent to debate about it.
I in essence asked for a debate, or arguments of what this "random" entails, and then how this might relate to a concept of God - while the second bit is philosophical, i made it an important point that i was intrested in the random part (which is scienfic )
It does not have anything to do with God. Your belief in your God has nothing to do with the scientific study of quantum mechanics. It is irrelevant to the study of quantum mechanics.
but to some extent, it does not mean for certain a lack of causation", rather a lack of measuring it... its a kind of semi-ignorance thing?
The universe is truly random. A particle truly has no specific value of property until that property is measured. It is not a matter of poor technology, or poor measurement technique. An electron with a precisely defined position can have any momentum at all, and no measurement technology will ever be able to make this not so. An electron whose position has not been measured yet has no defined position yet.
the result is a break down of determinism, in which we need to know the above.
Determinism does not seem to be the correct theory of the microscopic world. Probabilism seems to be.
but does this mean the universe is fundermentally random?
Yes.
while my maths is bloody awful i recall (from my undergrad days) that determinsic systems can yeild "random"
No. Deterministic systems cannot ever be truly random. As you said, chaotic systems and pseudorandom number generators can provide the "illusion" of randomness, but they cannot be truly random (since they're deterministic). Determinism and randomness are mutually exclusive properties.
so maybe the universe had an "origin" that was fundermentally determinstic - no does not have to be God
Could be. This question has nothing to do with quantum mechanics.
my other point is that has QM says that the oberver is very much apart of the system
No, it doesn't say that. Popularizers of quantum theory -- the people who write paperback books -- say that. Quantum mechanics does not deal with the philosophical meaning of measurement at all. Measurements, whether made by eye or by photodetector, result in the same effects.
and so "random" events might be assocated to degrees of freedom, one of which could be how we interact with our obervastion - maybe this makes some kind of blind spot??
The phrase 'degree of freedom' already has another meaning in the context of physical theory. Please don't attempt to redefine it.
on the EPR paradox, we are making on assumption, that i rarely see addressed, while atomic systems can NOT be seperated, and there is NO such thing has say an isolated electron
There can certainly be such thing as an isolated electron. The so-called free particle propagator describes what happens to the wavefunction of just such a particle.
the space in which we measure say one photon, with detector A and one at detector B... further along (with anther photon)... do we assume that the space-time, is in the prespective OF OUR SPACE, the large - BUT the photon, might be using its prespective, in which case: this experiment is meangless to it? - "space-time" is not smooth, to it - while to us it is.?????
I read this paragraph several times. I can only conclude it is gibberish. Photons do not have perspectives.
the upshot of this - assuming I am right here? - is that we are not measuring a quantum reality, we are in fact measuring, things as they appear in the context of a classically described apparatus! (Quantum phenomena!) the problems arise, when applying classical thought to this!
I don't know what this means, either.
- I hope you can now see, why I beleive we should get the science right, even If what I am saying is wrong! -
I think we scientists have every intention of getting the science right.

- Warren

Originally posted by agnostictheist
...the space in which we measure say one photon, with detector A and one at detector B... further along (with anther photon)... do we assume that the space-time, is in the prespective OF OUR SPACE, the large - BUT the photon, might be using its prespective, in which case: this experiment is meangless to it? - "space-time" is not smooth, to it - while to us it is.?????
I think you are trying to understand why photons obey different rules
to everyday objects? Putting yourself in the shoes of a photon doesn't really work terribly well though.

Originally posted by agnostictheist
the upshot of this - assuming I am right here? - is that we are not measuring a quantum reality, we are in fact measuring, things as they appear in the context of a classically described apparatus! (Quantum phenomena!) the problems arise, when applying classical thought to this!
I think you are saying that you can not easily get a direct experience of quantum mechanics. People get confused by trying to understand quantum mechanics using classical physics.

"No, it doesn't say that. Popularizers of quantum theory -- the people who write paperback books -- say that. Quantum mechanics does not deal with the philosophical meaning of measurement at all. Measurements, whether made by eye or by photodetector, result in the same effects."

back this up, I never talked about the philosophical meanings here:

"The phrase 'degree of freedom' already has another meaning in the context of physical theory. Please don't attempt to redefine it."

How can I redefine something, if i made no attempt to define it in the frist place?

i didnt dissuss quantity that can vary, eg componet of velocity

"There can certainly be such thing as an isolated electron. The so-called free particle propagator describes what happens to the wavefunction of just such a particle."

please explain!... and does this "isolation" mean that the obervers obervsation wont effect its "properties"?

"I read this paragraph several times. I can only conclude it is gibberish. Photons do not have perspectives."

Really? so if a time to a photon has no meaning it doesnt count has a perspective?

If you don't know what an inner product is, you obviously don't know quantum mechanics.
I never claimed I know QM, you missed my point totaly, I took issue with the fact that you almost assert, I have beguin QM... how do you propose I did my degree in chemistry, without some Knowlege of Quantum physics, thats not to say I KNOW ALL OF IT, or most.

If you are not willing to learn quantum mechanics, then there is little point in discussing anything about it with you.
I ask questions to learn, correct myself and debate - not because I already know the answers - unless I am very unsure of them.

You must learn a subject before you can be competent to debate about it.
No it doesnt - not always, one whom as little knowelege STILL can make at times important comments, on the other hand they run the risk of drawing up strawman arguments.

It does not have anything to do with God. Your belief in your God has nothing to do with the scientific study of quantum mechanics. It is irrelevant to the study of quantum mechanics.
I never actually disagreed with this, and in fact allot of what I wrote argees with this, my point was discussing "random".

The universe is truly random. A particle truly has no specific value of property until that property is measured. It is not a matter of poor technology, or poor measurement technique. An electron with a precisely defined position can have any momentum at all, and no measurement technology will ever be able to make this not so. An electron whose position has not been measured yet has no defined position yet.
I am sorry, but I spent time wriing the HUP, i never claimed that this is a result of poor results, or apparatus! I stated that what we use... the apparatus are bulit with within a classical framework, we see from a classical point of veiw, a quantum world, and that trying to bring classical though will arise contradictions!

so why do you say that the universe is thus RANDOM, instead of the universe has is randomness?

sure on the small probablity rules, but this does not mean everything is thus random or uncertain, it does mean that we cant know, the precise measurments of an electron (both postion and momentum)...and QM will tell us there is none. (but this is already colored with our pre-concepts in the macro-world!)

chroot
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Gold Member

Originally posted by agnostictheist
back this up, I never talked about the philosophical meanings here:
Of course you did. You said "my other point is that has QM says that the oberver is very much apart of the system". This is a philosophical viewpoint, on the level of an interpretation of quantum mechanics. It is not actually part of quantum mechanics. Quantum mechanics does not concern itself with what an observer is or is not.
please explain!... and does this "isolation" mean that the obervers obervsation wont effect its "properties"?
The wavefunction begins having one form. As the particle moves, its wavefunction changes to another form (somewhat gradually, of course). The "function" that describes how the free particle's wavefunction changes is called the "free particle propagator." If the particle is free, then there are no observers, rather by definition.
Really? so if a time to a photon has no meaning it doesnt count has a perspective?
I still have no idea what you meant with the original paragraph.
I never claimed I know QM, you missed my point totaly, I took issue with the fact that you almost assert, I have beguin QM... how do you propose I did my degree in chemistry, without some Knowlege of Quantum physics, thats not to say I KNOW ALL OF IT, or most.
I do assert that you don't know quantum mechanics, based both on the questions you ask, and the wacky things you claim the theory says. If you got a degree in Chemistry but don't know what an inner product of two vectors is, you should really demand a refund from your university.
I ask questions to learn, correct myself and debate - not because I already know the answers - unless I am very unsure of them.
You seem to be rather sure that you know things about quantum mechanics in this thread.
No it doesnt - not always, one whom as little knowelege STILL can make at times important comments, on the other hand they run the risk of drawing up strawman arguments.
The chances are slim -- very slim.
I am sorry, but I spent time wriing the HUP, i never claimed that this is a result of poor results, or apparatus!
Of course you did. You said " but to some extent, it does not mean for certain a lack of causation", rather a lack of measuring it... its a kind of semi-ignorance thing?". This indicates you'd rather believe the particles have complementary properties, but we lack the sophistication to precisely measure those properties. That is incorrect.
I stated that what we use... the apparatus are bulit with within a classical framework, we see from a classical point of veiw, a quantum world, and that trying to bring classical though will arise contradictions!
What is a "classical framework," and how does one build an apparatus within it?
so why do you say that the universe is thus RANDOM, instead of the universe has is randomness?
I'm not sure I understand the disctinction between "has" and "is" in this context. I mean that, when you measure the spin of an electron along some axis, you get either +1/2 or -1/2, randomly.
sure on the small probablity rules, but this does not mean everything is thus random or uncertain,
Are you suggesting it's possible to build a deterministic system from probabilistic parts? Perhaps you need to think about that some more -- it can't be done.
it does mean that we cant know, the precise measurments of an electron (both postion and momentum)...and QM will tell us there is none. (but this is already colored with our pre-concepts in the macro-world!)
Our preconceptions from the macroscopic world would have us believe the electron does have both its complementary properties at the same time. It seems this is not so, so we have abandoned those preconceptions, and embraced a new set of rules for the microscopic world.

- Warren

"Of course you did. You said "my other point is that has QM says that the oberver is very much apart of the system". This is a philosophical viewpoint, on the level of an interpretation of quantum mechanics. It is not actually part of quantum mechanics. Quantum mechanics does not concern itself with what an observer is or is not."

Just what do you mean by "what an observer is or is not? that is very vague - it could mean is, in the sense "conscience" or something else - please explain yourself!

i never said what or who, this observer is, rather the act of observation...effects what is being observed, i went on to ask you to back up what you said before, you have not.

"The wavefunction begins having one form. As the particle moves, its wavefunction changes to another form (somewhat gradually, of course). The "function" that describes how the free particle's wavefunction changes is called the "free particle propagator." If the particle is free, then there are no observers, rather by definition."

are you reffering to the wavefunction changes over time? -or is that something different?, when I said isolated, i meant that any obervers looking at it, wont in some way effect it!

you say they are no observers, why? - I though that separteness or locality is not allowed (at last in the CHI)

"I do assert that you don't know quantum mechanics, based both on the questions you ask, and the wacky things you claim the theory says."

with respect, half the things you assert I said are simply what you think I meant by it!

"If you got a degree in Chemistry but don't know what an inner product of two vectors is, you should really demand a refund from your university."

it was a degree in chemistry, not physicis.. why QM was needed we dont cover all topics, and unless you know the topics covered, you comment is pretty offbeat.

"You seem to be rather sure that you know things about quantum mechanics in this thread. "

you of course are allowed to think..and asserrt what you think i "seeming" - think i know of QM.

"Of course you did. You said " but to some extent, it does not mean for certain a lack of causation", rather a lack of measuring it... its a kind of semi-ignorance thing?". This indicates you'd rather believe the particles have complementary properties, but we lack the sophistication to precisely measure those properties. That is incorrect."

Why, why cant it mean from our prespective? within the universe, while we many have no right to dissuss..from a transcdent point of view, it would be wrong thus to assert, that our prespective is the ONLY One!

"What is a "classical framework," and how does one build an apparatus within it?"

we bulid experiments and measure, with from OUR PRESPECTIVE into the quantum!

"I'm not sure I understand the disctinction between "has" and "is" in this context. I mean that, when you measure the spin of an electron along some axis, you get either +1/2 or -1/2, randomly."

in this case then the random only extends to which where the spin..is either + or - not that there is total random.

"Are you suggesting it's possible to build a deterministic system from probabilistic parts? Perhaps you need to think about that some more -- it can't be done."

no, i am saying it may seem to be probabilistic... within certian context.

chroot
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Gold Member
Bah, I'm done. I'm not going to beat it into your head. Buy a book. Or don't.

- Warren

re

Bah, I'm done. I'm not going to beat it into your head. Buy a book. Or don't
odd that for example:

" An electron does not exist in isolation, because it can borrow energy from the uncertaninty relation, for a short enought time, and use it to create a photon" : In search of scrodingers cat By John Gribbin p196

yet you seem to disagree with my shorten version of this:

...while atomic systems can NOT be seperated, and there is NO such thing has say an isolated electron...

you state:

"There can certainly be such thing as an isolated electron. The so-called free particle propagator describes what happens to the wavefunction of just such a particle."

No, John was quite clear that there was no such thing, unless this was one of those paperback books your talking about, hence why (and with other comments you make) I asked you to support your "claims"... did you not really.

chroot
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Gold Member
I assume Gribbin is talking about vacuum fluctuations and virtual photons. It comes down to your definition of "isolated." My definition, the one followed in most treatises on QM, is simply that an isolated particle experiences uniformly zero potential. If you'd like to choose a different definition, that's fine.

And yes, this is one of the problems I have with paperback books -- they don't really teach the reader everything -- they teach the reader little bits and pieces, enough to whet the apetite. The reader then automatically does what humans do -- he amalgamates those bits and pieces into a cohesive world-view. Unfortunately, when you only have bits and pieces, that world-view you create is not likely to be correct. That's why the world is full of cocktail-party physicists who are so sure they're right, when they just aren't. I generally like the idea of teaching physics to the public, and I know people like Gribbin mean well. Unfortunately, many people seem to think a paperback by Gribbin is equivalent to an education is physics -- and it just isn't.

- Warren

I assume Gribbin is talking about vacuum fluctuations and virtual photons
you assume correct, and that photons can be formed has a result of electrons not existing in isolation (Which is why i menitioned a atomic system.

It comes down to your definition of "isolated."
Ok fair enough, people do have different difintions, and different concepts and ideas, and situtions... lead to different difintions, but lets make this clear - if you are aware of this, then its your duty to ask for clairfication, or to insure no cross wires!

My definition, the one followed in most treatises on QM, is simply that an isolated particle experiences uniformly zero potential. If you'd like to choose a different definition, that's fine.
I asked you before what i beleived to be fair questions they were:

are you reffering to the wavefunction changes over time? -or is that something different?, when I said isolated, i meant that any obervers looking at it, wont in some way effect it!

you say they are no observers, why? - I though that separteness or locality is not allowed (at last in the CHI)

Unfortunately, many people seem to think a paperback by Gribbin is equivalent to an education is physics -- and it just isn't.
this is true, however some people dont know or have access to all the info, so they tend to ask questions or basis the arguements on what they "known": and this are not assertions has such rather not proper statements of some sort (are you aware of Carnaps, schlicks - logical postivism - explinations of science ? ) which are open for correction, and addition.

PS: one obervation, which is not really IF CORRECT QM: when i said isolated electron.. that does not mean particles does it, yes an electron is a "particle" - when oberved that way - but electron is a form of particle, particles are not forms of electrons! it appears you might of confused the two, but that might be a result of me being misslead my the name "isolated particle experiences uniformly zero potential." on the other hand it does not nesscerly exlulde an electron.- in which case please explain my error.

also i would like to ask you something else:

The wavefunction begins having one form. As the particle moves, its wavefunction changes to another form (somewhat gradually, of course). The "function" that describes how the free particle's wavefunction changes is called the "free particle propagator." If the particle is free, then there are no observers, rather by definition.
how can it be a particle...and not be oberved? when "things" are not oberved, i though at last in the commman interpration of QM... it doesnt narrow down its options?

chroot
Staff Emeritus
Gold Member
Originally posted by agnostictheist
Ok fair enough, people do have different difintions, and different concepts and ideas, and situtions... lead to different difintions, but lets make this clear - if you are aware of this, then its your duty to ask for clairfication, or to insure no cross wires!
How am I supposed to know what you think the word 'isolated' means?
are you reffering to the wavefunction changes over time? -or is that something different?, when I said isolated, i meant that any obervers looking at it, wont in some way effect it!
If it's isolated, there are no observers -- rather by definition. All observations affect the system. There are no kinds of observations that do not. Observation of an observable quantity leaves the system in an eigenstate of that observable. This is a postulate of the theory.
this is true, however some people dont know or have access to all the info
PS: one obervation, which is not really IF CORRECT QM: when i said isolated electron.. that does not mean particles does it, yes an electron is a "particle" - when oberved that way - but electron is a form of particle, particles are not forms of electrons!
It does not matter.
how can it be a particle...and not be oberved? when "things" are not oberved, i though at last in the commman interpration of QM... it doesnt narrow down its options?
What narrows down what options? What are you talking about?

- Warren

Stingray

Originally posted by chroot
...No, it doesn't say that. Popularizers of quantum theory -- the people who write paperback books -- say that. Quantum mechanics does not deal with the philosophical meaning of measurement at all. Measurements, whether made by eye or by photodetector, result in the same effects.
I don't agree with this. Quantum mechanics must deal with the meaning (in some sense) of measurement, but it does so poorly. This is a shortcoming of the theory.

It is irrelevant to define the behavior of a field (wavefunction or density matrix) without precisely defining how that field can be observed. A "measurement" in quantum mechanics is an ambiguous concept. Considering the massive effect that it has on the dynamics of a system, it shouldn't be this way. I don't think anyone truly believes that human consciousness is required to collapse a state, so what is? To give a more specific example, Schrodinger's cat type effects are clearly wrong on the scale of a cat.

Further, if QM is a fundamental theory (which we have no reason to doubt), it applies to the measurement device as well as the system being measured. So the entire thing may be taken as a closed, unmeasured system evolving as states usually do. The second formulation has to give the same answer as the usual one that is used in quantum mechanics (probabilities). Mathematically, this is impossible (since the Hamiltonian is unitary), but the results could be arbitrarily close, which is good enough I think. In my opinion, this is one of the most remarkable results of quantum theory, yet I don't think it has ever been shown rigorously.

“How am I supposed to know what you think the word 'isolated' means?”

A question, which is pretty irrelevant, the issue is not about what you know or don’t know,
What I think I mean, rather if you don’t know, yet still comment – despite the fact your unaware of what I mean by a term, yet you still claim one to be wrong, or right… how do you know. In short you don’t you just said so.

That’s why I added the point that one seeks to know what definition being used – you didn’t!

“If it's isolated, there are no observers -- rather by definition”

Ok so why would it be called a particle? “Electron” maybe, (has they have wave/particle duality ) but your system does not have an oberver, at all!! –

“All observations affect the system. There are no kinds of observations that do not”

yes I agree

“Observation of an observable quantity leaves the system in an eigenstate of that observable. This is a postulate of the theory.”

And that eigenstate, in part forms the basis for the next set of wavefunctions… but when “we” are not looking at it… remember you said there are no observers – how the hell can you call it a particle, QM DOES not tell us what a system is like when we are NOT looking at it, you seem to assert, that it does!

Also you asserted before the universe IS random, why such a strong assertation?

The Schrödinger equation is determinsic in the sense that, given a wavefunction at an initial time, it makes a definite prediction of what the wavefunction will be at any later time. During a measurement, the eigenstate to which the wavefunction collapses is probabilistic, not deterministic. (Has we cant say which values we get with certainty) The probabilistic nature of quantum mechanics thus stems from the act of measurement.

Did I not say that the random could be a result or our observation?

And yes, here is where interpretations fit in, but I would say they should be addressed. – while the correct context stated

nice try, but somewhat ignorant, A library does not always contain valid information in fact, neither do all “textbooks” and the way in which some subjects are teach, Libraries tend to holds lots of those paperbacks you so much tend have a problem with, not to mention the scope and quality and quantity of info, did you ever wonder why I said:

rather than… to info

“How am I supposed to know what you think the word 'isolated' means?”

A question, which is pretty irrelevant, the issue is not about what you know or don’t know,
What I think I mean, rather if you don’t know, yet still comment – despite the fact your unaware of what I mean by a term, yet you still claim one to be wrong, or right… how do you know. In short you don’t you just said so.

That’s why I added the point that one seeks to know what definition being used – you didn’t!

“If it's isolated, there are no observers -- rather by definition”

Ok so why would it be called a particle? “Electron” maybe, (has they have wave/particle duality ) but your system does not have an oberver, at all!! –

“All observations affect the system. There are no kinds of observations that do not”

yes I agree

“Observation of an observable quantity leaves the system in an eigenstate of that observable. This is a postulate of the theory.”

And that eigenstate, in part forms the basis for the next set of wavefunctions… but when “we” are not looking at it… remember you said there are no observers – how the hell can you call it a particle, QM DOES not tell us what a system is like when we are NOT looking at it, you seem to assert, that it does!

Also you asserted before the universe IS random, why such a strong assertation?

The Schrödinger equation is determinsic in the sense that, given a wavefunction at an initial time, it makes a definite prediction of what the wavefunction will be at any later time. During a measurement, the eigenstate to which the wavefunction collapses is probabilistic, not deterministic. (Has we cant say which values we get with certainty) The probabilistic nature of quantum mechanics thus stems from the act of measurement.

Did I not say that the random could be a result or our observation?

And yes, here is where interpretations fit in, but I would say they should be addressed. – while the correct context stated

nice try, but somewhat ignorant, A library does not always contain valid information in fact, neither do all “textbooks” and the way in which some subjects are teach, Libraries tend to holds lots of those paperbacks you so much tend have a problem with, not to mention the scope and quality and quantity of info, did you ever wonder why I said:

rather than… to info

chroot
Staff Emeritus
Gold Member
Originally posted by agnostictheist
That’s why I added the point that one seeks to know what definition being used – you didn’t!
You didn't seek it, so why should I have? Why is it my responsibility to learn how to speak a language used only by you, rather than your responsibility to learn how to speak a language spoken by all of us? I have no interest in learning your language, because it is not useful to me.
Ok so why would it be called a particle?
Electrons are a type of particle. All particles have the same wave/particle duality. It's perfectly fair to just call them 'particles.'
And that eigenstate, in part forms the basis for the next set of wavefunctions… but when “we” are not looking at it… remember you said there are no observers – how the hell can you call it a particle, QM DOES not tell us what a system is like when we are NOT looking at it, you seem to assert, that it does!
So wait, it's only a particle if there's an observer? What is it called if there's no observer? A whoosawhatsit?

QM tells us what the wavefunction of a particle does with measurement (i.e. you can calculate the probability of collapse into each eigenstate of the observable) and without (i.e. you can determine how the wavefunction changes over time). So, certainly, QM tells us what the system is like without observation. That's what a theory DOES -- it predicts what will happen when you observe things. This necessarily also involves predicting what will happen between those observations.
Also you asserted before the universe IS random, why such a strong assertation?
Becuase, at each observation, the wavefunction collapses randomly into one of the eigenstates.
The probabilistic nature of quantum mechanics thus stems from the act of measurement.
This is a sort of awkward statement, but okay. I understand what you're saying. It is true that probabilism only gets involved when the system is observed.
Did I not say that the random could be a result or our observation?
"An observation" of a particle can be performed by bouncing a photon off of it. The photon may or may not have something to do with a human observer. The particle behaves the same way regardless of where the photon came from, or who's watching the result. "Our observation" is irrelevant.
And yes, here is where interpretations fit in, but I would say they should be addressed. – while the correct context stated
You can say it all you like. An interpretation of a theory is not a theory itself.
nice try, but somewhat ignorant, A library does not always contain valid information in fact, neither do all “textbooks” and the way in which some subjects are teach, Libraries tend to holds lots of those paperbacks you so much tend have a problem with, not to mention the scope and quality and quantity of info, did you ever wonder why I said:
Don't read the paperbacks then, read the good books. What is your problem? Are you really so defensive that you're willing to argue that a library does not contain books that tell you what I am telling you? Give me a break!

- Warren

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You didn't seek it, so why should I have?
thats something a two year old might say!, and they and you would
would be lame to claim:

the issue is NOT that i have to seek it, or that you must know what I mean by X, it is that you seem to at easy to still state what X might be being true or false, yet either you don't know what it was meant to mean - which is pretty idiotic! one does not make comments on something they are dont know were the convo is going.

OR

- you maybe aware at first, that a term had different meanings and context, yet you still concluded a select one, so even your best senerio, you seem to have rushed to an unsound conclusion!

Why is it my responsibility to learn how to speak a language used only by you,

rather than your responsibility to learn how to speak a language spoken by all of us?
it is now is it, again its not very relevent, coz the issue was not languge, and even if it was - how am I supose to know what lang your speaking, and since you were claim that there are diferent defintions of some terms, you think you would of been more careful.

Electrons are a type of particle
Not nesscerly - and its a very missleading statement, more one this later.

All particles have the same wave/particle duality. It's perfectly fair to just call them 'particles.'
depends on your context, and under what conditions... but WAIT here is a little more... o and by the way notice the circular reasoning of your statement?

So wait, it's only a particle if there's an observer? What is it called if there's no observer? A whoosawhatsit?
No you missed the point AGAIN! havent you? take an electron for example while it is has you say got wave/particle duality! calling an electron a particle is stupid, UNLESS its obervered to be so under CERTAIN conditions! in short an OBJECT (eg: electron)behaves as a particle OR as a wave DEPENDING on OUR choice of apparatus for looking at it: COMPLEMENTARITY

So wait, it's only a particle if there's an observer? What is it called if there's no observer? A whoosawhatsit?[/
Even those you reconise the fact there is daulity, you dont carry the reasoning through, take our electron its not a particle nor can you really call it so in diffraction waves in crystals using x-rays!

you got the daulity right, shame about the scienfic languge really

QM tells us what the wavefunction of a particle does with measurement (i.e. you can calculate the probability of collapse into each eigenstate of the observable) and without (i.e. you can determine how the wavefunction changes over time).
How can you determine the probablity of outcomes without frist knowing the intail wavefunction - you cant! We may have something in state A with then goes to B, but we can never know whats happing inbetween, for all we know, we could even be measuring a different "object"

In fact that wonderful book In search of scrodingers cat, actually flatly contradicts you, that QM DOES NOT tell us or offers an explination or argue...whatever you like to call it, what say an electron is doing when we are not looking at it (in fact its meaningless to do so)... So I am going to ask you to provide some form of online - but formal, and scienfically respected site, link to support your claim. - that means dont simply re-write what you just said.

Becuase, at each observation, the wavefunction collapses randomly into one of the eigenstates.
that could be a interpration or an "illusion" for example evertt offers a POSSIBLE explination to this, which can be seen as determinstic, but has we "live" in our slice of the cake, it appears its random.

An observation" of a particle can be performed by bouncing a photon off of it. The photon may or may not have something to do with a human observer.
I have never stated "whom" or what this observer is!! you seem to be responding to claims I have not made - again

You can say it all you like. An interpretation of a theory is not a theory itself.
correct JUST like what you and I say about the collapse of the wavefunction. or do you think you some how immune, or have an experiment in mind, that can once and for all argue for one or the other if so... please show it!

not all library have them...or do you think they HAVE TO or ALL do... that would be a very impressive claim.

chroot
Staff Emeritus
Gold Member
Originally posted by agnostictheist
thats something a two year old might say!
Funny, you said it first. If you can't use physicist's language, we won't be able to get far in this discussion. I don't have the patience to try to translate into whatever words you'd rather me use.
in short an OBJECT (eg: electron)behaves as a particle OR as a wave DEPENDING on OUR choice of apparatus for looking at it: COMPLEMENTARITY
So we're hung up on language yet again. It is true, there is only one kind of object at microscopic scales, which behaves sometimes like a macroscopic particle (localized in space) and sometimes like a macroscopic wave (localized in momentum space). Physicsts just call these 'quantum mechanical objects' particles, despite the confusion it has obviously caused you. It's just a word. Physicists are perfectly comfortable saying that a quantum-mechanical particle has a wavelength. Calling an electron a particle does not indicate that it does not have wave character, also. Some people have proposed using the word 'wavicle,' but who really cares? It's just a word, and we know what the word particle means. Now you do, also.
In fact that wonderful book In search of scrodingers cat, actually flatly contradicts you, that QM DOES NOT tell us or offers an explination or argue...whatever you like to call it, what say an electron is doing when we are not looking at it (in fact its meaningless to do so)...
This is the classic problem with reading books like that. You don't really understand the theory, so you're interpreting what Gribbin wrote incorrectly. You think you understand quantum mechanics, but you don't. If you'd like me to teach you, I will. If you want to argue with me, sod off. If you think you know more than me (a professional physicst) because you've read Gribbin's book, sod off. I don't care if you ever understand it.
So I am going to ask you to provide some form of online - but formal, and scienfically respected site, link to support your claim. - that means dont simply re-write what you just said.
http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/qm2.html#c6
http://www.magres.nottingham.ac.uk/teaching/qm/lectures/time_evolution/time_evolution.html

The time evolution of a wavefunction is found by using the time-dependent Schrodinger equation.

Now, I find it rather insulting that you're asking me (a trained physicist) to provide references to information that's freely available, because you feel some paperback book told you otherwise. You know how to use google, don't you? (Type in "time evolution wavefunction.") You know how to operate a library card, don't you? SO DO IT.
that could be a interpration or an "illusion" for example evertt offers a POSSIBLE explination to this, which can be seen as determinstic, but has we "live" in our slice of the cake, it appears its random.
MWI is again an interpretation. I am not very interested in discussing the interpretations. I am interested in showing you what the theory itself says.

- Warren

Funny, you said it first. If you can't use physicist's language, we won't be able to get far in this discussion. I don't have the patience to try to translate into whatever words you'd rather me use.
again, I see your focusing on something which was not really the issue! but its really up to you if you want this ongoing issue.

It's just a word, and we know what the word particle means. Now you do, also.
I agree it was a lang problem.. now maybe you see why WE must explain what we mean (and this is not a dig, but is this a forum to disuss QM or a forum FOR ONLY physicist's?)

This is the classic problem with reading books like that. You don't really understand the theory, so you're interpreting what Gribbin wrote incorrectly. You think you understand quantum mechanics, but you don't.
stop putting words into my mouth, while I accept that I am using a book (for novices), I dont assert that the book is like hold all the anwsers, I have not disagreed with you comment of paperback books (those at time it might be too strongly put) nor have I said I understand QM... you said that of me!

If you'd like me to teach you, I will. If you want to argue with me,
by all means teach me... I have no problem with this. But what is the issue is how do teach a non-physicist, some physics, without some defining! (no not taking diggs... its a reasonible point!!)

The time evolution of a wavefunction is found by using the time-dependent Schrodinger equation.
but it starts from an intail (oberved) wavefunction right?

would it be fair to say, that if we have a starting point like this, with was somewhat "isolated" then it will proced form A(oberved) --- to --- B (oberved), and in this sense its sort of "determinsic"??

if that is so, then not all things are effected by obervation? hence "free of external interactions"

what sort of "particles" would do this? - and how can we distigush these from simply most prossible.

does this wavefunction (can it) contain many eigenstates?

Now, I find it rather insulting that you're asking me (a trained physicist) to provide references to information that's freely available, because you feel some paperback book told you otherwise. You know how to use google, don't you? (Type in "time evolution wavefunction.") You know how to operate a library card, don't you? SO DO IT.
if you feel insulted, for being asked to provide evidence or to back up a claim, then has a scientist, you must be very insulted for most of the time, for the record its not that I dont beleive you rather I need a some source that validates what you say, for all I know your not a trained phycists.(thats not a insult)

I am a trained chemist, and also a biomedical scientist, I dont simply accept peoples points, nor did I assert this book is right, I wanted you to show me a few, sources - thats all. and ask questions

MWI is again an interpretation. I am not very interested in discussing the interpretations. I am interested in showing you what the theory itself says.
I AM aware that the MWI is an interpretation I SAID THAT, but what I am saying is that the wavefuntion yes collapse, but to say its "random" is also an interpretation?

when wavefunction collapse, WHY does it?...due to obervation right? inducing a probablistic effect?

but were do the other states Go?

if they are loss, then i am going to ask, why do they have to be loss, and saying they are lossed could be simply throwing arms into the air and saying i give up!

yes these move into the philosophies but, then so does the conclusion of the universe being random, even those some determinstic ideas are now shown to be "wrong" or rather limited to context.

the random could be an illusion of sorts, thats why its unfair to say the theory says it IS random

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