How and why does measuring a particle make its wavefunction collapse,

[Alan McDougall]

How and why does measuring a particle make its wavefunction collapse,

producing the concrete reality that we perceive to exist? The issue, known as

the measurement problem, may seem mysterious, but understanding of what

reality is, or if it exists at all, hinges upon the answer.

 

Thus can physics anwer this question yet?

 

 

 

[swansont]

The result of a measurement must be an eigenvalue of an observable, so the system must end up in an eigenstate.

[Sharapovaphan]

The result of a measurement must be an eigenvalue of an observable, so the system must end up in an eigenstate.

 

haha!... Schrödinger's Cat!

 

BTW, I thought you might get a chuckle out of this... A response to the question as to the proper pronunciation of Schrödinger: "There are actually two ways to pronounce his name, but you won't know which you've chosen until after you've said it."

[Alan McDougall]

The result of a measurement must be an eigenvalue of an observable, so the system must end up in an eigenstate.

 

Einstein once said "you dont really understand something yourself, unless you can explain it to your grandmother"

 

How does the eigenvalue answer the question of, How and why does measuring a particle make its wavefunction collapse.?

Edited September 23, 2012 by Alan McDougall

[swansont]

Einstein once said "you dont really understand something yourself, unless you can explain it to your grandmother"

 

How does the eigenvalue answer the question of, How and why does measuring a particle make its wavefunction collapse.?

The systems have to be in an allowed state when you measure them; that's one of the ramifications of QM. That's why the collapse must occur.

[JvNrocks]

According to the impeccable axiomatic mathematics of John von Neumann in 1932, only "conscious" observation of the wavefunction's contents makes it "collapse."

Edited September 24, 2012 by JvNrocks

[O'Nero Samuel]

According to the impeccable axiomatic mathematics of John von Neumann in 1932, only "conscious" observation of the wavefunction's contents makes it "collapse."

Does that mean its appears to collapse but really doesn't?

[Alan McDougall]

According to the impeccable axiomatic mathematics of John von Neumann in 1932, only "conscious" observation of the wavefunction's contents makes it "collapse."

 

Does this mean there is something mysterious operating at the fundamental level that in reality we dont understand?

[Ronald Hyde]

Maybe less like Schrödinger's Cat than Lewis Carrol's Cheshire Cat. The atom changes from eigenstate to eigenstate and the wavfunction only tells us what the chances are

at any time to make that change. The wavefunction is the cat, the eigenstate is the grin that you observe.

[Alan McDougall]

Maybe less like Schrödinger's Cat than Lewis Carrol's Cheshire Cat. The atom changes from eigenstate to eigenstate and the wavfunction only tells us what the chances are

at any time to make that change. The wavefunction is the cat, the eigenstate is the grin that you observe.

 

It seems to me we know know how it happens, eg by measuring or observing the wavefunction collapse, but why it happens is still a puzzle.

[Sharapovaphan]

Hmmm. : )

 

http://www.kurzweilai.net/forums/topic/quantum-physics-is-common-sense-particle-when-observed-wave-if-not-i-know-why

Edited September 26, 2012 by Sharapovaphan

[Ronald Hyde]

It seems to me we know know how it happens, eg by measuring or observing the wavefunction collapse, but why it happens is still a puzzle.

It may indeed know why it's doing what it does, but it completely fails to tell us, yet lets us write a mathematical function that gives us

the odds.

[EquisDeXD]

How and why does measuring a particle make its wavefunction collapse,

producing the concrete reality that we perceive to exist? The issue, known as

the measurement problem, may seem mysterious, but understanding of what

reality is, or if it exists at all, hinges upon the answer.

 

Thus can physics anwer this question yet?

 

 

 

 

You just answered it yourself, because its a function, a function can only have one output per input, i.e. one probability per measurement.

[Alan McDougall]

You just answered it yourself, because its a function, a function can only have one output per input, i.e. one probability per measurement.

 

Really! heck I am cleverer than I thought

[Sharapovaphan]

Probability gives way to functionality at the moment of observation. Has observation been defined clearly enough? Is it even possible to completely define it? Can all existing parameters be identified to a 100% certainty? Does wave collapse occur when the blind observe (blind from birth)? Would not the blind through other senses have to somehow "see" in their mind, our reality, in order to present data in our reality?

[juanrga]

How and why does measuring a particle make its wavefunction collapse,

producing the concrete reality that we perceive to exist? The issue, known as

the measurement problem, may seem mysterious, but understanding of what

reality is, or if it exists at all, hinges upon the answer.

 

Thus can physics anwer this question yet?

 

First, the physical reality already exists before the measurement. This is a basic assumption behind the theory of measurements.

 

In the last decades different dynamical models of the collapse has been developed. Still remain some details, but they are more technical than foundational. Using those models you can 'see' how the wavefunction collapses to some of the eigenstate when the system interacts with the measurement apparatus.

[chandragupta]

The particle & its wave function are both phenomena which are perceived by the observer. The answer to your question is hidden in the paradigm as to whether the universe can exist independent of the observer, not withstanding the discovery by the observer of millions of years old fossils & that the universe is 13.7 billion years old. Your thoughts?

[juanrga]

The particle & its wave function are both phenomena which are perceived by the observer. The answer to your question is hidden in the paradigm as to whether the universe can exist independent of the observer, not withstanding the discovery by the observer of millions of years old fossils & that the universe is 13.7 billion years old. Your thoughts?

 

Wave functions are not observable, but mathematical objects. Particles are 'perceived' by other particles as well.

 

Quantum mechanics is perfectly compatible with a universe which exists independent of the observer. In quantum cosmology we consider earlier stages of the universe when no human was born. No paradigm here.

[chandragupta]

1351422827[/url]' post='710773']

Wave functions are not observable, but mathematical objects. Particles are 'perceived' by other particles as well.

 

Quantum mechanics is perfectly compatible with a universe which exists independent of the observer. In quantum cosmology we consider earlier stages of the universe when no human was born. No paradigm here.

 

Observer is the only existence in universe who is not only 'self-aware' but is also 'other-aware'. Here the phrase 'other-aware' applies to matter which is neither 'self-aware' nor 'other-aware'. Even if ONE ACCEPTS FOR ARGUMENT SAKE that matter can exist independent of the observer I.e. in the absence of the observer, the question will remain as to who is going to proclaim 'Hey, look there is THIS thing WHOM I call MATTER WHO CAN EXIST INDEPENDENT OF ME'. Your thoughts?

[Alan McDougall]

Observer is the only existence in universe who is not only 'self-aware' but is also 'other-aware'. Here the phrase 'other-aware' applies to matter which is neither 'self-aware' nor 'other-aware'. Even if ONE ACCEPTS FOR ARGUMENT SAKE that matter can exist independent of the observer I.e. in the absence of the observer, the question will remain as to who is going to proclaim 'Hey, look there is THIS thing WHOM I call MATTER WHO CAN EXIST INDEPENDENT OF ME'. Your thoughts?

 

You really might find this link very interesting.

[chandragupta]

1351434750[/url]' post='710787']

You really might find this link very interesting.

 

Thanks. I shall enjoy this.

 

1348534214[/url]' post='704196']

Does this mean there is something mysterious operating at the fundamental level that in reality we dont understand?

 

Yes. It is called ' OBSERVER'.

 

1348414422[/url]' post='703964']

haha!... Schrödinger's Cat!

 

BTW, I thought you might get a chuckle out of this... A response to the question as to the proper pronunciation of Schrödinger: "There are actually two ways to pronounce his name, but you won't know which you've chosen until after you've said it."

 

You have beautiful insight about ' strangeness ' of this amazing universe of ours.

 

1348416670[/url]' post='703971']

Einstein once said "you dont really understand something yourself, unless you can explain it to your grandmother"

 

How does the eigenvalue answer the question of, How and why does measuring a particle make its wavefunction collapse.?

 

Very true.

 

1348495689[/url]' post='704107']

According to the impeccable axiomatic mathematics of John von Neumann in 1932, only "conscious" observation of the wavefunction's contents makes it "collapse."

 

Would you be kind enough to explain in simple terms this ' IMPECCABLE AXIOMATIC MATHEMATICS OF JOHN NEWMAN (1932) THAT CONSCIOUS OBSERVATION OF THE WAVE- FUNCTION'S CONTENTS MAKES IT COLLAPSE.

 

1347993615[/url]' post='703129']

The result of a measurement must be an eigenvalue of an observable, so the system must end up in an eigenstate.

 

Would you be kind enough to explain in very simple understandable terms:- What these two words namely 'EIGENVALUE & EIGENSTATE MEAN?

[swansont]

Ran across this, and it applies to part of this thread (and several others)

http://arxiv.org/abs/1301.1069

 

"A Snapshot of Foundational Attitudes Toward Quantum Mechanics"

 

While this was not a scientific survey, I think it's telling that it was a very small minority (6%) that thought that consciousness was required to qualify as being required for the observer to collapse the wave function.

 

"Popular accounts have sometimes suggested that the Copenhagen interpretation attributes such a role to consciousness. In our view, this is to misunderstand the Copenhagen interpretation."

[MigL]

We don't observe objects ( whether macroscopic or quantum ) nor collapse their wavefunctions ( ? ).

 

What we do is observe interactions, since any object that does not interact with anything else is unobservable. Look at all the trouble finding dark matter ( which still interacts gravitationaly )..

 

I would propose it is the interaction which renders probability too reality ( what some members call 'collapsing the wavefunction' ).

[Bill Angel]

How and why does measuring a particle make its wavefunction collapse,producing the concrete reality that we perceive to exist? The issue, known as the measurement problem, may seem mysterious, but understanding of what reality is, or if it exists at all, hinges upon the answer.Thus can physics anwer this question yet?

One avenue of investigation that I don't think anyone has mentioned is related to the concept of "quantum decoherence".

To quote from the wiki article on this subject:

decoherence does not attempt to explain the measurement problem . Rather, decoherence provides an explanation for the transition of the system to a mixture of states that seem to correspond to those states observers perceive.

[Mike Smith Cosmos]

One avenue of investigation that I don't think anyone has mentioned is related to the concept of "quantum decoherence". To quote from the wiki article on this subject:

 

Does not observation ,include all the other non conscious observations that cause this collapse ?

 

 

namely: The universe is going about its business in all its own ways and the ways we know about through our physics. But when one particle or another , makes demand on another particle ( say by shared orbitals or whatever ) THEN such interactions demand more, and thus cause the waveform collapse at that interaction. ? Thus wave form collapsing and re-establishing, is going on Apace all about the universe, and in that way the universe becomes the reality we perceive. Underneath where things work better at the quantum mechanical level, things go about their respective business with all the freedom (offered by the probability wave-function) allows.

 

I other words , as requested in laymans language :-

.

 

. " It is the touching of the quantum fields is how the cosmos is being made"

 

.

Edited January 19, 2013 by Mike Smith Cosmos