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Dec 13, 2012, 1:01:37 PM12/13/12

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The results of measurements of phase entangled particles together with

Bell's theorem provide pretty convincing evidence that the Universe

contains non-local interactions.

Yet I'm lead to wonder.

Let's imagine the usual idealised experimental scenario, where there is

an emitter of particles in a twin state and measurement devices

performing measurements in a space-like separated way, with the results

then brought together for comparison. We know that when performed

appropriately, this will show that the measurement results are

correlated in a way that, by Bell's theorem, cannot be explained by any

local interaction - the measurements are non-locally linked, and thus

the Universe is non-local.

Now step back. Consider that the above is performed in complete

isolation, except that the results of the final step - comparison of the

measurements, is transmitted to an outside observer.

Since the experiment, except for the last step, is performed in

isolation, the outside observer can regard the entire experimental

situation as a superposition of quantum states with no decoherence

except at the last step. The "measurements" are nothing but further

entanglements between the twin sate particles and the measuring

apparatus. The last step involves an interaction between particles that

represent the results of the earlier "measurements", with the sets of

particles for the two measurements for a given twin state pair of

particles being already entangled. Those particles now further interact

locally to produce the transmitted result of the comparison to the

outside observer.

So the outside observer can calculate the evolution of the system, and

the final transmitted results, without needing to assume any non-local

interactions. In particular, the outside observer cannot use Bell's

theorem to prove that the system is non-local.

From this perspective, it looks as if the appearance of non-locality in

the system results from a false assumption by observers embedded in the

system that they are somehow independent of it, and that their

measurement results are determined before they are compared.

Sylvia.

Bell's theorem provide pretty convincing evidence that the Universe

contains non-local interactions.

Yet I'm lead to wonder.

Let's imagine the usual idealised experimental scenario, where there is

an emitter of particles in a twin state and measurement devices

performing measurements in a space-like separated way, with the results

then brought together for comparison. We know that when performed

appropriately, this will show that the measurement results are

correlated in a way that, by Bell's theorem, cannot be explained by any

local interaction - the measurements are non-locally linked, and thus

the Universe is non-local.

Now step back. Consider that the above is performed in complete

isolation, except that the results of the final step - comparison of the

measurements, is transmitted to an outside observer.

Since the experiment, except for the last step, is performed in

isolation, the outside observer can regard the entire experimental

situation as a superposition of quantum states with no decoherence

except at the last step. The "measurements" are nothing but further

entanglements between the twin sate particles and the measuring

apparatus. The last step involves an interaction between particles that

represent the results of the earlier "measurements", with the sets of

particles for the two measurements for a given twin state pair of

particles being already entangled. Those particles now further interact

locally to produce the transmitted result of the comparison to the

outside observer.

So the outside observer can calculate the evolution of the system, and

the final transmitted results, without needing to assume any non-local

interactions. In particular, the outside observer cannot use Bell's

theorem to prove that the system is non-local.

From this perspective, it looks as if the appearance of non-locality in

the system results from a false assumption by observers embedded in the

system that they are somehow independent of it, and that their

measurement results are determined before they are compared.

Sylvia.

Dec 15, 2012, 8:32:12 AM12/15/12

to

n

> the system results from a false assumption by observers embedded in the

> system that they are somehow independent of it, and that their

> measurement results are determined before they are compared.

>

> Sylvia.

xxein: Is there the possibility that the the measurement apparati is
> the system results from a false assumption by observers embedded in the

> system that they are somehow independent of it, and that their

> measurement results are determined before they are compared.

>

> Sylvia.

flawed and non-accountable for real interpretation?

I ask this in the wonderment of whether the aperture size it fitting

the polarization profile for the object's detection. But, mostly, it

appears that a gravity function may be detected because this could be

considered as a differential to any local measurement as a hidden

local but non-local variable. Always confusing, isn't it?

I am referring to a graph that shows the difference between quantum

measurements and the 'local real' predictions of relativity amongst

the angles of detection (the apparent cosine function that shows the

variance).

I have not thought about Bell's theorem exemplified in this way before

so I may just be wrong in my offering. At the same 'time' it may be

enlightening to some wishing to explore this further.

If we really knew the physic...

Dec 15, 2012, 8:32:33 AM12/15/12

to

On 12/13/2012 7:01 PM, Sylvia Else wrote:

> The results of measurements of phase entangled particles together with

> Bell's theorem provide pretty convincing evidence that the Universe

> contains non-local interactions.

But the results are never in contradiction with local quantum
> The results of measurements of phase entangled particles together with

> Bell's theorem provide pretty convincing evidence that the Universe

> contains non-local interactions.

field theory! So where do you see this evidence?

> Yet I'm lead to wonder.

>

> Let's imagine the usual idealised experimental scenario, where there is

> an emitter of particles in a twin state and measurement devices

> performing measurements in a space-like separated way, with the results

> then brought together for comparison. We know that when performed

> appropriately, this will show that the measurement results are

> correlated in a way that, by Bell's theorem, cannot be explained by any

> local interaction

local interactions (in the emitter of the twin state) and

has spread with less than the speed of light.

> - the measurements are non-locally linked, and thus

> the Universe is non-local.

that this needs non-local *interactions*? (As you claimed!)

...

> So the outside observer can calculate the evolution of the system, and

> the final transmitted results, without needing to assume any non-local

> interactions.

An inside observer can do the same calculation. Or do you
> the final transmitted results, without needing to assume any non-local

> interactions.

see a problem there? This observer will then realize that

they are in a superposition of states. (The singular "they"

as pronoun makes sense here even without the aim of being

gender-neutral..)

> From this perspective, it looks as if the appearance of non-locality in

> the system results from a false assumption by observers embedded in the

> system that they are somehow independent of it,

a superposition (entangled with each other). And of course

the criticism only holds for those observers that make

this assumption! Prudent observers will accept that they

are entangled, and no non-local interaction is necessary.

They might still be surprised by how smoothly the decoherence

of their state of mind happens! (You don't usually observe

your own entanglement, as far as I can see..)

> and that their

> measurement results are determined before they are compared.

the different possible results are all still present as

a probability amplitude. You can look at subspaces of the

Hilbert space where you project out all but one set of

consistent results, but that doesn't mean the rest of the

Hilbert space ceases to exist! So nothing is "determined".

And the fact that decoherence (largely) suppresses the

interaction between subspaces still doesn't mean that only

one subspace remains in existence.

Just the fact that we don't observe the other subspaces

(where other sets of results were measured) cannot serve

as proof that those have collapsed from existence!

--

Jos

Dec 15, 2012, 8:46:05 AM12/15/12

to

On Thu, 13 Dec 2012 18:01:37 +0000, Sylvia Else alluded :

> From this perspective, it looks as if the appearance of non-locality in

> the system results from a false assumption by observers embedded in the

> system that they are somehow independent of it, and that their

> measurement results are determined before they are compared.

yes, the correlation info is transmitted faster than the speed of light

> From this perspective, it looks as if the appearance of non-locality in

> the system results from a false assumption by observers embedded in the

> system that they are somehow independent of it, and that their

> measurement results are determined before they are compared.

Dec 16, 2012, 1:40:44 AM12/16/12

to

On 16/12/2012 12:32 AM, Jos Bergervoet wrote:

> On 12/13/2012 7:01 PM, Sylvia Else wrote:

>> The results of measurements of phase entangled particles together with

>> Bell's theorem provide pretty convincing evidence that the Universe

>> contains non-local interactions.

>

> But the results are never in contradiction with local quantum

> field theory! So where do you see this evidence?

One needs to be clear that Bell's theorem does not in any way predict
> On 12/13/2012 7:01 PM, Sylvia Else wrote:

>> The results of measurements of phase entangled particles together with

>> Bell's theorem provide pretty convincing evidence that the Universe

>> contains non-local interactions.

>

> But the results are never in contradiction with local quantum

> field theory! So where do you see this evidence?

results that differ from QM. In the early days, it might have appeared

that Bell's theorem suggested experiments (Aspect's being the first)

that would falsify QM because Bell's theorem proved that no non-local

real model could lie behind QM and locality have been taken as a given.

In the event, Aspect's result was consistent with QM, meaning that

whatever modem lies behind QM, it has to be non-local, or some other

assumtion in Bell's theorem has to be false.

Bell's theorem seems conclusive on this point. If we assume that a

measurement leads to an immediate and definite result, then the

correlation between the results of measurements on phase entangled

particles cannot be explained by a purely local model.

>

>> Yet I'm lead to wonder.

>>

>> Let's imagine the usual idealised experimental scenario, where there is

>> an emitter of particles in a twin state and measurement devices

>> performing measurements in a space-like separated way, with the results

>> then brought together for comparison. We know that when performed

>> appropriately, this will show that the measurement results are

>> correlated in a way that, by Bell's theorem, cannot be explained by any

>> local interaction

>

> OK, you need the global entanglement. But it is caused by

> local interactions (in the emitter of the twin state) and

> has spread with less than the speed of light.

>

>> - the measurements are non-locally linked, and thus

>> the Universe is non-local.

>

> There exists non-local entanglement, but how can you prove

> that this needs non-local *interactions*? (As you claimed!)

all, and purely in terms of decisions made during an experiment, and the

observations that result. See something I've prepared on this at

http://www.cryogenic.net/BellsTheorem.pdf

>

> ...

>> So the outside observer can calculate the evolution of the system, and

>> the final transmitted results, without needing to assume any non-local

>> interactions.

>

> An inside observer can do the same calculation. Or do you

> see a problem there? This observer will then realize that

> they are in a superposition of states. (The singular "they"

> as pronoun makes sense here even without the aim of being

> gender-neutral..)

they are in a superposition of states, then the issue goes away, because

they are no longer assuming, as Bell's Theorem requires, that the

measurement produces an immediate and definite result. The observer

accepts that nothing is definitely resolved (if it ever is), until their

results are compared with those of the other observer, at the earliest.

>

>> From this perspective, it looks as if the appearance of non-locality in

>> the system results from a false assumption by observers embedded in the

>> system that they are somehow independent of it,

>

> The false assumption seems to be that they reject being in

> a superposition (entangled with each other). And of course

> the criticism only holds for those observers that make

> this assumption! Prudent observers will accept that they

> are entangled, and no non-local interaction is necessary.

discussion was an irritation about the number of experiments that seem

to be reported that purport to show the speed of some presumed influence

that travels between the measurements at multiples of the speed of

light, or even "instantaneously" (which is means little). Absent a proof

(which I believe will not be forthcoming) that the measurement results

are immediate and definite, those expreiments seem rather pointless, and

the claims of FTL influences (which nevertheless remain out of reach of

direct examination) are entirely spurious.

>

> They might still be surprised by how smoothly the decoherence

> of their state of mind happens! (You don't usually observe

> your own entanglement, as far as I can see..)

>

Indeed no.
> They might still be surprised by how smoothly the decoherence

> of their state of mind happens! (You don't usually observe

> your own entanglement, as far as I can see..)

>

>> and that their

>> measurement results are determined before they are compared.

>

> Here I cannot follow you.. If there is entanglement then

> the different possible results are all still present as

> a probability amplitude. You can look at subspaces of the

> Hilbert space where you project out all but one set of

> consistent results, but that doesn't mean the rest of the

> Hilbert space ceases to exist! So nothing is "determined".

> And the fact that decoherence (largely) suppresses the

> interaction between subspaces still doesn't mean that only

> one subspace remains in existence.

>

> Just the fact that we don't observe the other subspaces

> (where other sets of results were measured) cannot serve

> as proof that those have collapsed from existence!

>

suggesting is already accepted by a substantial part of the physics

community. Just not those who do FTL influence style experiments.

Sylvia.

Dec 16, 2012, 3:35:44 AM12/16/12

to

the problem of deciding whether two received photons are actually

members of the same pair. This has to be inferred from the fact that

they are received at nearly the same time (suitably adjusted, where

necessary for known propogation delays). However, the consquence of

counting two photons as paired when they are not should be to reduce the

observed correlation, so that should not be a problem provided that it

doesn't happen so often as to reduce the correlation below the maximum

posited by Bell's theorem for a purely local system.

Another is that in practice, because so many of the photons are not

detected, the simple limit proposed by Bell is not testable. Instead

there are rather involved mathematical extrapolations that determine a

different limit that the actual experimental situation must exceed for

it to be possible to infer that the ideal experiment would exceed Bell's

limit. These extrapolations might be subtlely flawed, despite being peer

reviewed.

Yet another is the possibility that the Universe is just outright

cheating. For example, unless the choices of orientation of the

polarisation detectors is made so close to each other in time that no

subluminal (i.e. local) message could pass between them, then the

Universe might send a message by an unknown, but subluminal means and

decide on the outcomes such that Bell's limit is exceeded even though

the mechanism is actually purely local. Various strategies have been

used to prevent this, to the point where every known loophole has been

closed, but no single experiment has closed all the loopholes at the

same time. Unless the Universe is being truely capricious in a way that

requires intelligence, it's hard to see that these loopholes can really

still compromise the result.

> I ask this in the wonderment of whether the aperture size it fitting

> the polarization profile for the object's detection. But, mostly, it

> appears that a gravity function may be detected because this could be

> considered as a differential to any local measurement as a hidden

> local but non-local variable. Always confusing, isn't it?

>

> I am referring to a graph that shows the difference between quantum

> measurements and the 'local real' predictions of relativity amongst

> the angles of detection (the apparent cosine function that shows the

> variance).

>

> I have not thought about Bell's theorem exemplified in this way before

> so I may just be wrong in my offering. At the same 'time' it may be

> enlightening to some wishing to explore this further.

>

> If we really knew the physic...

>

"Just Bell's Theorem". In that version, I have attempted to show just

how little the actual physics impacts on the conclusion of non-locality.

Sylvia.

Dec 18, 2012, 12:49:14 PM12/18/12

to

"Sylvia Else" <syl...@not.at.this.address> wrote in message

news:aj4t4p...@mid.individual.net...

topology for an EPR-Bohm scenario. Please see Joy Christian's "Disproof

of Bell's Theorem".

http://arxiv.org/abs/1201.0775

"On the Origins of Quantum Correlations"

http://arxiv.org/find/grp_physics/1/au:+christian_j/0/1/0/all/0/1

http://www.brownwalker.com/book.php?method=ISBN&book=1599425645

"Disproof of Bell's Theorem; Illuminating the Illusion of Entanglement"

Though Bell's theorem is mathematically proven, that doesn't mean it has

been physically proven. Dr. Christian has successfully shown that when

a parallelized 3-sphere topology is chosen for the EPR-Bohm scenario,

quantum mechanics is local and realistic. Furthermore, he has shown

generally that a parallelized 7-sphere topology can explain all quantum

correlations. For those that might be more interested in the

topological aspects please see the discussion on the FQXi blog at the

following link.

http://www.fqxi.org/community/forum/topic/1352#post_71101

> Bell's theorem seems conclusive on this point. If we assume that a

> measurement leads to an immediate and definite result, then the

> correlation between the results of measurements on phase entangled

> particles cannot be explained by a purely local model.

Yes, they can be explained by a purely local model. See the above

links.

Best,

Fred Diether

news:aj4t4p...@mid.individual.net...

> On 16/12/2012 12:32 AM, Jos Bergervoet wrote:

>> On 12/13/2012 7:01 PM, Sylvia Else wrote:

>>> The results of measurements of phase entangled particles together with

>>> Bell's theorem provide pretty convincing evidence that the Universe

>>> contains non-local interactions.

>>

>> But the results are never in contradiction with local quantum

>> field theory! So where do you see this evidence?

>

> One needs to be clear that Bell's theorem does not in any way predict

> results that differ from QM. In the early days, it might have appeared

> that Bell's theorem suggested experiments (Aspect's being the first)

> that would falsify QM because Bell's theorem proved that no non-local

> real model could lie behind QM and locality have been taken as a given.

> In the event, Aspect's result was consistent with QM, meaning that

> whatever modem lies behind QM, it has to be non-local, or some other

> assumtion in Bell's theorem has to be false.

Yes, Bell made a *physical* mistake in not specifying the correct
>> On 12/13/2012 7:01 PM, Sylvia Else wrote:

>>> The results of measurements of phase entangled particles together with

>>> Bell's theorem provide pretty convincing evidence that the Universe

>>> contains non-local interactions.

>>

>> But the results are never in contradiction with local quantum

>> field theory! So where do you see this evidence?

>

> One needs to be clear that Bell's theorem does not in any way predict

> results that differ from QM. In the early days, it might have appeared

> that Bell's theorem suggested experiments (Aspect's being the first)

> that would falsify QM because Bell's theorem proved that no non-local

> real model could lie behind QM and locality have been taken as a given.

> In the event, Aspect's result was consistent with QM, meaning that

> whatever modem lies behind QM, it has to be non-local, or some other

> assumtion in Bell's theorem has to be false.

topology for an EPR-Bohm scenario. Please see Joy Christian's "Disproof

of Bell's Theorem".

http://arxiv.org/abs/1201.0775

"On the Origins of Quantum Correlations"

http://arxiv.org/find/grp_physics/1/au:+christian_j/0/1/0/all/0/1

http://www.brownwalker.com/book.php?method=ISBN&book=1599425645

"Disproof of Bell's Theorem; Illuminating the Illusion of Entanglement"

Though Bell's theorem is mathematically proven, that doesn't mean it has

been physically proven. Dr. Christian has successfully shown that when

a parallelized 3-sphere topology is chosen for the EPR-Bohm scenario,

quantum mechanics is local and realistic. Furthermore, he has shown

generally that a parallelized 7-sphere topology can explain all quantum

correlations. For those that might be more interested in the

topological aspects please see the discussion on the FQXi blog at the

following link.

http://www.fqxi.org/community/forum/topic/1352#post_71101

> Bell's theorem seems conclusive on this point. If we assume that a

> measurement leads to an immediate and definite result, then the

> correlation between the results of measurements on phase entangled

> particles cannot be explained by a purely local model.

links.

Best,

Fred Diether

Dec 18, 2012, 8:52:27 PM12/18/12

to

[[Mod. note -- I have rewrapped paragraph-length lines. -- jt]]

There is a lot of confusion over these issues, and I think they all

come about because of faulty beliefs about how the world works. I

don't claim to have it figured out, but I'd like to suggest some

ideas I think have promise:

-One major problem with attributing a result at one location to a

"measurement" at another is Relativity. If we accept that Relativity

is correct then we cannot have a consistent version of physics and

still assert that the detection of a particle at A "causes" a certain

result at point B which is spacelike separated from A. Any assertion

of faster than light interactions violates Relativity, and I'm

inclined not to accept that yet.

-An underlying assumption in all talk about entangled particles is

that they somehow are emitted from the source without any knowledge

of where they are going to end up. This is certainly a very intuitive

assumption that agrees with our daily experience. Historically it

is a result of a philosophical debate in the late 1800's that ended

up rejecting action at a distance. Einstein certainly rejected

"spooky action at a distance". I'm starting to wonder if maybe

action at a distance should be reconsidered however.

-The "entangled particle" experiments can make perfect sense if you

allow action at a distance, but consistent with Relativity. That

is, in Relativity there is a concept of null lines. These are

simply points in space-time that have zero separation as calculated

via the metric. i.e. all points on a common light cone (either

past or future) have zero separation from the vertex of the light

cones. If we take this zero separation literally (and I think most

don't), then in a sense the emitter of a photon and the detector

can interact directly because they have "zero separation". If the

emitter is restricted to emitting a photon only when it has a place

to land, then at the moment of emission all requirements for

conservation of energy, polarization, etc. can be satisfied. If

two photons are being emitted by some process at the same time,

presumably both photons must have a place to go before emission,

and both must satisfy applicable conservation laws. This is a

picture that is Relativistic-ally consistent, and also consistent

with QM. I think this is a tough idea for many people to swallow,

especially when they understand its implications. I'm not convinced

myself, although I find the idea intriguing.

-This view can be consistent with QM because the emitter can randomly

choose any available receiver on its future light cone to send the

photon, provided the applicable conservation laws are satisfied.

I think the current assumption is that an atom emits its photon

into space, and the photon then moves out at the speed of light and

interacts with matter until it is destroyed. It has been observed,

however, that if an atom is in a space that cannot support the

emitted photon (e.g. a resonant cavity), the atom will not emit the

photon. This too seems consistent with the idea that the emitter

interacts with the receiver in some way prior to emission.

Wheeler?Feynman absorber theory seems to do something like this,

as does the Transactional interpretation of QM.

Just some comments...

Rich L.

There is a lot of confusion over these issues, and I think they all

come about because of faulty beliefs about how the world works. I

don't claim to have it figured out, but I'd like to suggest some

ideas I think have promise:

-One major problem with attributing a result at one location to a

"measurement" at another is Relativity. If we accept that Relativity

is correct then we cannot have a consistent version of physics and

still assert that the detection of a particle at A "causes" a certain

result at point B which is spacelike separated from A. Any assertion

of faster than light interactions violates Relativity, and I'm

inclined not to accept that yet.

-An underlying assumption in all talk about entangled particles is

that they somehow are emitted from the source without any knowledge

of where they are going to end up. This is certainly a very intuitive

assumption that agrees with our daily experience. Historically it

is a result of a philosophical debate in the late 1800's that ended

up rejecting action at a distance. Einstein certainly rejected

"spooky action at a distance". I'm starting to wonder if maybe

action at a distance should be reconsidered however.

-The "entangled particle" experiments can make perfect sense if you

allow action at a distance, but consistent with Relativity. That

is, in Relativity there is a concept of null lines. These are

simply points in space-time that have zero separation as calculated

via the metric. i.e. all points on a common light cone (either

past or future) have zero separation from the vertex of the light

cones. If we take this zero separation literally (and I think most

don't), then in a sense the emitter of a photon and the detector

can interact directly because they have "zero separation". If the

emitter is restricted to emitting a photon only when it has a place

to land, then at the moment of emission all requirements for

conservation of energy, polarization, etc. can be satisfied. If

two photons are being emitted by some process at the same time,

presumably both photons must have a place to go before emission,

and both must satisfy applicable conservation laws. This is a

picture that is Relativistic-ally consistent, and also consistent

with QM. I think this is a tough idea for many people to swallow,

especially when they understand its implications. I'm not convinced

myself, although I find the idea intriguing.

-This view can be consistent with QM because the emitter can randomly

choose any available receiver on its future light cone to send the

photon, provided the applicable conservation laws are satisfied.

I think the current assumption is that an atom emits its photon

into space, and the photon then moves out at the speed of light and

interacts with matter until it is destroyed. It has been observed,

however, that if an atom is in a space that cannot support the

emitted photon (e.g. a resonant cavity), the atom will not emit the

photon. This too seems consistent with the idea that the emitter

interacts with the receiver in some way prior to emission.

Wheeler?Feynman absorber theory seems to do something like this,

as does the Transactional interpretation of QM.

Just some comments...

Rich L.

Dec 19, 2012, 4:00:59 AM12/19/12

to

Rich L. <ralivi...@sbcglobal.net> wrote:

> [...] If we accept that Relativity is correct then we cannot have

Doesn't matter which "caused" the other. There's no possible problem

until information about the outcomes of both measurements eventually

becomes simultaneously available at some single point/event,

which will obviously be in the future lightcone of both measurements.

Until that happens, nobody knows nothing about any possible correlation.

Supopose you have two different observers, both in the future lightcone

of both measurements, but relatively moving so that one thinks

A caused B, and the other thinks B caused A. Doesn't matter.

Both see total spin (or whatever) zero, and each can validly/consistently

speculate whatever they like about which caused which. Either the

-1/2 measurement "caused" the +1/2 measurement, or vice versa.

Not a meaningful concept, e.g., in a causal set poset, the two separate

measurement events would be (causally) incomparable. But everything

physically meaningful, like total spin when initially prepared,

will work out consistently.

--

John Forkosh ( mailto: j...@f.com where j=john and f=forkosh )

> [...] If we accept that Relativity is correct then we cannot have

> a consistent version of physics and still assert that the detection

> of a particle at A "causes" a certain result at point B which is

> spacelike separated from A. Rich L.
> of a particle at A "causes" a certain result at point B which is

Doesn't matter which "caused" the other. There's no possible problem

until information about the outcomes of both measurements eventually

becomes simultaneously available at some single point/event,

which will obviously be in the future lightcone of both measurements.

Until that happens, nobody knows nothing about any possible correlation.

Supopose you have two different observers, both in the future lightcone

of both measurements, but relatively moving so that one thinks

A caused B, and the other thinks B caused A. Doesn't matter.

Both see total spin (or whatever) zero, and each can validly/consistently

speculate whatever they like about which caused which. Either the

-1/2 measurement "caused" the +1/2 measurement, or vice versa.

Not a meaningful concept, e.g., in a causal set poset, the two separate

measurement events would be (causally) incomparable. But everything

physically meaningful, like total spin when initially prepared,

will work out consistently.

--

John Forkosh ( mailto: j...@f.com where j=john and f=forkosh )

Dec 20, 2012, 11:18:19 AM12/20/12

to

and B", and then at a future time A' and B' meet up and compare results.

But so do A" and B", and in a space-like separated way from the meeting

between A' and B'.

So even at the meeting between A' and B', or A" and B", there is still

nothing definite that can be said about the measurements, but the

comparisons appear to have become entangled as well, because they have

to give the same results if they in turn are compared at some common

point in the further future.

Of course, that argument can be continued ad infinitum.

Sylvia.

Dec 20, 2012, 11:19:25 AM12/20/12

to

[[Mod. note -- In this posting as received, every 2nd line of the quoted

text was blank. I have removed these quoted blank lines. -- jt]]

On Wednesday, December 19, 2012 3:00:59 AM UTC-6, JohnF wrote:

> Rich L. <ralivi...@sbcglobal.net> wrote:

> > [...] If we accept that Relativity is correct then we cannot have

> > a consistent version of physics and still assert that the detection

> > of a particle at A "causes" a certain result at point B which is

> > spacelike separated from A. Rich L.

>

> Doesn't matter which "caused" the other. There's no possible problem

> until information about the outcomes of both measurements eventually

> becomes simultaneously available at some single point/event,

> which will obviously be in the future lightcone of both measurements.

> Until that happens, nobody knows nothing about any possible correlation.

> Supopose you have two different observers, both in the future lightcone

> of both measurements, but relatively moving so that one thinks

> A caused B, and the other thinks B caused A. Doesn't matter.

> Both see total spin (or whatever) zero, and each can validly/consistently

> speculate whatever they like about which caused which. Either the

> -1/2 measurement "caused" the +1/2 measurement, or vice versa.

> Not a meaningful concept, e.g., in a causal set poset, the two separate

> measurement events would be (causally) incomparable. But everything

> physically meaningful, like total spin when initially prepared,

> will work out consistently.

>

This response, I think, shows another confusion we have. Some interpret QM to mean that an event hasn't really happened until some person perceives it. In other words, there is no issue about the correlation between what happens at A and B until some person is able to examine both events and wonder about the correlation. There is good reason for this idea, even though I question it myself. There are situations, such as a "photon" reflecting off a diffraction grating, that strongly imply that the photon simultaneously reflected off of each of the facets of the grating at the same time. This raises the questions about the reality of simultaneous alternate paths the photon (or other particle) can take, and what constitutes a measurement (where the wave function "collapses" into a definite single state.

I would like to think that the world does its thing independent of any intelligent being perceiving or wondering about what is happening. That the events at A and B happen, and show what ever correlation they show without any dependence on who observes those events. I realize that this is contrary to some interpretations of QM, and brings us to the difficult question of "What is a measurement?". I am trying to come up with an interpretation of QM that would make all this clearer. I think that reconsidering action at a distance might do that, but I can't claim to have that answered yet. My opinions on all this are probably a bit out of the mainstream.

Rich L.

text was blank. I have removed these quoted blank lines. -- jt]]

On Wednesday, December 19, 2012 3:00:59 AM UTC-6, JohnF wrote:

> Rich L. <ralivi...@sbcglobal.net> wrote:

> > [...] If we accept that Relativity is correct then we cannot have

> > a consistent version of physics and still assert that the detection

> > of a particle at A "causes" a certain result at point B which is

> > spacelike separated from A. Rich L.

>

> Doesn't matter which "caused" the other. There's no possible problem

> until information about the outcomes of both measurements eventually

> becomes simultaneously available at some single point/event,

> which will obviously be in the future lightcone of both measurements.

> Until that happens, nobody knows nothing about any possible correlation.

> Supopose you have two different observers, both in the future lightcone

> of both measurements, but relatively moving so that one thinks

> A caused B, and the other thinks B caused A. Doesn't matter.

> Both see total spin (or whatever) zero, and each can validly/consistently

> speculate whatever they like about which caused which. Either the

> -1/2 measurement "caused" the +1/2 measurement, or vice versa.

> Not a meaningful concept, e.g., in a causal set poset, the two separate

> measurement events would be (causally) incomparable. But everything

> physically meaningful, like total spin when initially prepared,

> will work out consistently.

>

I would like to think that the world does its thing independent of any intelligent being perceiving or wondering about what is happening. That the events at A and B happen, and show what ever correlation they show without any dependence on who observes those events. I realize that this is contrary to some interpretations of QM, and brings us to the difficult question of "What is a measurement?". I am trying to come up with an interpretation of QM that would make all this clearer. I think that reconsidering action at a distance might do that, but I can't claim to have that answered yet. My opinions on all this are probably a bit out of the mainstream.

Rich L.

Dec 27, 2012, 2:29:25 AM12/27/12

to

Below are two followups I submitted, twice, to spr

but which never appeared, and no email comments from

moderator, either. So I've posted them here, and

emailed RichL and SylviaE where to find them.

------------------------------------------------------------------------

followup to Rich L

------------------------------------------------------------------------

Rich L. <ralivi...@sbcglobal.net> wrote:

> [[Mod. note -- removed quoted blank lines. -- jt]]

> Rich L.

>

My reason for it is as follows. It's not so much a person perceiving it,

but rather an apparatus registering it. That is, if you want to say that

"correlation" is an actual physical observable, then you'd better

be able to build a device that blinks once for "yes" or twice for "no"

(or anything like that). And that device necessarily needs the outcomes

of both measurements available to it. Until that becomes possible,

in the future lightcone of both measurements, there can be no such

apparatus, and hence no such physical observable.

------------------------------------------------------------------------

followup to Sylvia E

------------------------------------------------------------------------

The key fact of your example is, I believe, when you correctly

say that that "they [both] have to give the same results".

And that fact effectively means there's no entanglement,

at least not in the usual "quantum mystery" kind of way...

Consider the following analogous situation. We usually prepare

an entangled pair of electrons in a total spin 0 state to

illustrate the "quantum mystery". But suppose instead that we

have a preparation device that prepares the pair in a total

spin 1 state. Are they still entangled now? Let's see: they've

been prepared entangledly because the preparation device

prepared them as a pair, not as two distinguishbale particles.

On the other hand, we already know their measurement outcomes:

it's |+1/2> for both. That is, "they [both] have to give the

same result", exactly like your remark above.

The elucidation is, I believe, as follows. When prepared in

a total spin 0 state, each electron is in a (mysterious quantum)

superposition state, |+1/2> + |-1/2> (properly normalized).

But when prepared in a total spin 1 state, each electron winds

up in the same (less mysterious) |+1/2> state, no superposition

necessary. And your example above is of that "less mysterious"

no-superposition variety.

but which never appeared, and no email comments from

moderator, either. So I've posted them here, and

emailed RichL and SylviaE where to find them.

------------------------------------------------------------------------

followup to Rich L

------------------------------------------------------------------------

Rich L. <ralivi...@sbcglobal.net> wrote:

> [[Mod. note -- removed quoted blank lines. -- jt]]

> JohnF wrote:

>> Rich L. <ralivi...@sbcglobal.net> wrote:

>> > [...] If we accept that Relativity is correct then we cannot have

>> > a consistent version of physics and still assert that the detection

>> > of a particle at A "causes" a certain result at point B which is

>> > spacelike separated from A. Rich L.

>>

>> Doesn't matter which "caused" the other. There's no possible problem

>> until information about the outcomes of both measurements eventually

>> becomes simultaneously available at some single point/event,

>> which will obviously be in the future lightcone of both measurements.

>> Until that happens, nobody knows nothing about any possible correlation.

>> Supopose you have two different observers, both in the future lightcone

>> of both measurements, but relatively moving so that one thinks

>> A caused B, and the other thinks B caused A. Doesn't matter.

>> Both see total spin (or whatever) zero, and each can validly/consistently

>> speculate whatever they like about which caused which. Either the

>> -1/2 measurement "caused" the +1/2 measurement, or vice versa.

>> Not a meaningful concept, e.g., in a causal set poset, the two separate

>> measurement events would be (causally) incomparable. But everything

>> physically meaningful, like total spin when initially prepared,

>> will work out consistently.

>> Rich L. <ralivi...@sbcglobal.net> wrote:

>> > [...] If we accept that Relativity is correct then we cannot have

>> > a consistent version of physics and still assert that the detection

>> > of a particle at A "causes" a certain result at point B which is

>> > spacelike separated from A. Rich L.

>>

>> Doesn't matter which "caused" the other. There's no possible problem

>> until information about the outcomes of both measurements eventually

>> becomes simultaneously available at some single point/event,

>> which will obviously be in the future lightcone of both measurements.

>> Until that happens, nobody knows nothing about any possible correlation.

>> Supopose you have two different observers, both in the future lightcone

>> of both measurements, but relatively moving so that one thinks

>> A caused B, and the other thinks B caused A. Doesn't matter.

>> Both see total spin (or whatever) zero, and each can validly/consistently

>> speculate whatever they like about which caused which. Either the

>> -1/2 measurement "caused" the +1/2 measurement, or vice versa.

>> Not a meaningful concept, e.g., in a causal set poset, the two separate

>> measurement events would be (causally) incomparable. But everything

>> physically meaningful, like total spin when initially prepared,

>> will work out consistently.

>> John Forkosh ( mailto: j...@f.com where j=john and f=forkosh )

>

> This response, I think, shows another confusion we have.

> Some interpret QM to mean that an event hasn't really happened

> until some person perceives it. In other words, there is no issue

> about the correlation between what happens at A and B until some person

> is able to examine both events and wonder about the correlation.

> There is good reason for this idea, even though I question it myself.

> [snip]
>

> This response, I think, shows another confusion we have.

> Some interpret QM to mean that an event hasn't really happened

> until some person perceives it. In other words, there is no issue

> about the correlation between what happens at A and B until some person

> is able to examine both events and wonder about the correlation.

> There is good reason for this idea, even though I question it myself.

> Rich L.

>

My reason for it is as follows. It's not so much a person perceiving it,

but rather an apparatus registering it. That is, if you want to say that

"correlation" is an actual physical observable, then you'd better

be able to build a device that blinks once for "yes" or twice for "no"

(or anything like that). And that device necessarily needs the outcomes

of both measurements available to it. Until that becomes possible,

in the future lightcone of both measurements, there can be no such

apparatus, and hence no such physical observable.

------------------------------------------------------------------------

followup to Sylvia E

------------------------------------------------------------------------

Sylvia Else <syl...@not.at.this.address> wrote:

> JohnF wrote:

>> Rich L. <ralivi...@sbcglobal.net> wrote:

>>> [...] If we accept that Relativity is correct then we cannot have

>>> a consistent version of physics and still assert that the detection

>>> of a particle at A "causes" a certain result at point B which is

>>> spacelike separated from A. Rich L.

>>

>> Doesn't matter which "caused" the other. There's no possible problem

>> until information about the outcomes of both measurements eventually

>> becomes simultaneously available at some single point/event,

>> which will obviously be in the future lightcone of both measurements.

>> Until that happens, nobody knows nothing about any possible correlation.

>> Supopose you have two different observers, both in the future lightcone

>> of both measurements, but relatively moving so that one thinks

>> A caused B, and the other thinks B caused A. Doesn't matter.

>> Both see total spin (or whatever) zero, and each can validly/consistently

>> speculate whatever they like about which caused which. Either the

>> -1/2 measurement "caused" the +1/2 measurement, or vice versa.

>> Not a meaningful concept, e.g., in a causal set poset, the two separate

>> measurement events would be (causally) incomparable. But everything

>> physically meaningful, like total spin when initially prepared,

>> will work out consistently.

>>

> JohnF wrote:

>> Rich L. <ralivi...@sbcglobal.net> wrote:

>>> [...] If we accept that Relativity is correct then we cannot have

>>> a consistent version of physics and still assert that the detection

>>> of a particle at A "causes" a certain result at point B which is

>>> spacelike separated from A. Rich L.

>>

>> Doesn't matter which "caused" the other. There's no possible problem

>> until information about the outcomes of both measurements eventually

>> becomes simultaneously available at some single point/event,

>> which will obviously be in the future lightcone of both measurements.

>> Until that happens, nobody knows nothing about any possible correlation.

>> Supopose you have two different observers, both in the future lightcone

>> of both measurements, but relatively moving so that one thinks

>> A caused B, and the other thinks B caused A. Doesn't matter.

>> Both see total spin (or whatever) zero, and each can validly/consistently

>> speculate whatever they like about which caused which. Either the

>> -1/2 measurement "caused" the +1/2 measurement, or vice versa.

>> Not a meaningful concept, e.g., in a causal set poset, the two separate

>> measurement events would be (causally) incomparable. But everything

>> physically meaningful, like total spin when initially prepared,

>> will work out consistently.

>>

> Though both A and B can be split into pairs observers A' and A", and B'

> and B", and then at a future time A' and B' meet up and compare results.

> But so do A" and B", and in a space-like separated way from the meeting

> between A' and B'.

>

> So even at the meeting between A' and B', or A" and B", there is still

> nothing definite that can be said about the measurements, but the

> comparisons appear to have become entangled as well, because they have

> to give the same results if they in turn are compared at some common

> point in the further future.

> Sylvia.
> and B", and then at a future time A' and B' meet up and compare results.

> But so do A" and B", and in a space-like separated way from the meeting

> between A' and B'.

>

> So even at the meeting between A' and B', or A" and B", there is still

> nothing definite that can be said about the measurements, but the

> comparisons appear to have become entangled as well, because they have

> to give the same results if they in turn are compared at some common

> point in the further future.

The key fact of your example is, I believe, when you correctly

say that that "they [both] have to give the same results".

And that fact effectively means there's no entanglement,

at least not in the usual "quantum mystery" kind of way...

Consider the following analogous situation. We usually prepare

an entangled pair of electrons in a total spin 0 state to

illustrate the "quantum mystery". But suppose instead that we

have a preparation device that prepares the pair in a total

spin 1 state. Are they still entangled now? Let's see: they've

been prepared entangledly because the preparation device

prepared them as a pair, not as two distinguishbale particles.

On the other hand, we already know their measurement outcomes:

it's |+1/2> for both. That is, "they [both] have to give the

same result", exactly like your remark above.

The elucidation is, I believe, as follows. When prepared in

a total spin 0 state, each electron is in a (mysterious quantum)

superposition state, |+1/2> + |-1/2> (properly normalized).

But when prepared in a total spin 1 state, each electron winds

up in the same (less mysterious) |+1/2> state, no superposition

necessary. And your example above is of that "less mysterious"

no-superposition variety.

Dec 28, 2012, 4:07:17 AM12/28/12

to

On 12/20/2012 5:19 PM, Rich L. wrote:

...

QM? With a Hamiltonian that gives unitary evolution

of a solution vector describing the experiment and

the observers you get everything you ask for in the

above!

> and brings us to the difficult question of "What

> is a measurement?". I am trying to come up with

> an interpretation of QM that would make all this

> clearer.

What exactly do you find unclear about a Hamiltonian

that gives unitary evolution of a solution vector

describing the experiment and the observers?

> I think that reconsidering action at a distance

> might do that,

Might do what?! Why shouldn't we use the existing

mathematical description?

--

Jos

...

> I would like to think that the world does its thing

> independent of any intelligent being perceiving or

> wondering about what is happening. That the events

> at A and B happen, and show what ever correlation

> they show without any dependence on who observes

> those events. I realize that this is contrary to

> some interpretations of QM,

Then why don't you stick to the basic equations of
> independent of any intelligent being perceiving or

> wondering about what is happening. That the events

> at A and B happen, and show what ever correlation

> they show without any dependence on who observes

> those events. I realize that this is contrary to

> some interpretations of QM,

QM? With a Hamiltonian that gives unitary evolution

of a solution vector describing the experiment and

the observers you get everything you ask for in the

above!

> and brings us to the difficult question of "What

> is a measurement?". I am trying to come up with

> an interpretation of QM that would make all this

> clearer.

that gives unitary evolution of a solution vector

describing the experiment and the observers?

> I think that reconsidering action at a distance

> might do that,

mathematical description?

--

Jos

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