## Two EPR questions

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no, scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\nFirst, I\'m curious how one can explain the EPR paradox in relativistic\nQFT, since one sets (as I understand it, anyway) [q1(x1),q2(x2)]=0\nwhen x1 and x2 are spacelike related points and q1 and q2 are\narbitrary operators. This seems to destroy the possibility of having\nEPR states. Why doesn\'t it?\n\nSecondly, in considering Bell\'s proof that hidden variable theories\nhave to be nonlocal, isn\'t there a loophole in the sense that no\nmatter how one constructs the experiment (even if one uses quantum\nprocesses to choose the polarization measurement orientations) there\nwould be no way to really get "random" orientations since the theory\nis, in fact, deterministic? That is, in some way the initial\nconditions which set up the whole experiment would determine what\nmeasurements would be made as well, thereby getting rid of the need\nfor nonlocal effects. Not that I think this is a particularly\nattractive loophole, since it raises all sorts of questions about how\nthe information would be stored about which measurement would be made,\nbut I\'m still curious if its technically a loophole.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>First, I'm curious how one can explain the EPR paradox in relativistic
QFT, since one sets (as I understand it, anyway) $[q1(x1),q2(x2)]=0$
when x1 and x2 are spacelike related points and q1 and q2 are
arbitrary operators. This seems to destroy the possibility of having
EPR states. Why doesn't it?

Secondly, in considering Bell's proof that hidden variable theories
have to be nonlocal, isn't there a loophole in the sense that no
matter how one constructs the experiment (even if one uses quantum
processes to choose the polarization measurement orientations) there
would be no way to really get "random" orientations since the theory
is, in fact, deterministic? That is, in some way the initial
conditions which set up the whole experiment would determine what
measurements would be made as well, thereby getting rid of the need
for nonlocal effects. Not that I think this is a particularly
attractive loophole, since it raises all sorts of questions about how
but I'm still curious if its technically a loophole.
 PhysOrg.com physics news on PhysOrg.com >> Study provides better understanding of water's freezing behavior at nanoscale>> Soft matter offers new ways to study how ordered materials arrange themselves>> Making quantum encryption practical


Blake Winter wrote: > Secondly, in considering Bell's proof that hidden variable theories > have to be nonlocal, isn't there a loophole in the sense that no > matter how one constructs the experiment (even if one uses quantum > processes to choose the polarization measurement orientations) there > would be no way to really get "random" orientations since the theory > is, in fact, deterministic? That is, in some way the initial > conditions which set up the whole experiment would determine what > measurements would be made as well, thereby getting rid of the need > for nonlocal effects. Not that I think this is a particularly > attractive loophole, since it raises all sorts of questions about how > the information would be stored about which measurement would be made, > but I'm still curious if its technically a loophole. Yes, it is, but it is a very small loophole. I've seen it used by people who obviously had no conception of how *very* small it is. What makes it so small is that Bell's theorem is violated for *all* mechanisms for deciding which measurements to make (at least all that have been tried). To take advantage of that loophole would require "nature" do do something equivalent to reverse engineering the apparatus to figure out how the decision depends on quantum events (if at all). The *exact* workings, to the last logic gate out of millions, of your pseudo random number generator would have to be taken into account, just to decide on the state of one photon. It would require "The Lord" to be more than subtle, more than malicious, but deliberately and fiendishly deceptive. If that were so, locality would be the *least* of our problems. It's like the possibility that the world was created in seven days, and only a week ago, complete with fossils and our memories. You can't rule it out, but at that level you can't rule *anything* out. Ralph Hartley



blake.winter@houghton.edu (Blake Winter) wrote in message news:<87423d2a.0409261455.69146e11@p...google.com>... > First, I'm curious how one can explain the EPR paradox in relativistic > QFT, since one sets (as I understand it, anyway) $[q1(x1),q2(x2)]=0$ > when x1 and x2 are spacelike related points and q1 and q2 are > arbitrary operators. This seems to destroy the possibility of having > EPR states. Why doesn't it? My understanding is that paired detection attributes in, say, optical Bell experiments are related insofar as they correspond to paired photons produced via the same atomic emission(s). If so, then because emission-paired photons *incident on* the analyzers are polarized identically (via conservation of angular momentum), then you get nonlinear data graphs when you plot the rates of coincidental detection (identical detection attributes) for the various angular differences $(\theta)$ of analyzer settings. > > Secondly, in considering Bell's proof that hidden variable theories > have to be nonlocal, isn't there a loophole in the sense that no > matter how one constructs the experiment (even if one uses quantum > processes to choose the polarization measurement orientations) there > would be no way to really get "random" orientations since the theory > is, in fact, deterministic? Varying the analyzer settings (randomly, pseudorandomly, or however) while the photons are in flight shouldn't matter anyway -- because, for any given pair of detection attributes there's one and only one corresponding $\theta$. > That is, in some way the initial conditions which set up the whole > experiment would determine what measurements would be made as well, > thereby getting rid of the need for nonlocal effects. There's no need for 'nonlocal effects' anyway, imo. Bell showed that if you model the biparticle setup in a certain way, then you'll get expectation values which are incompatible with qm for some $\theta$. And, if you believe the subsequent experiments, then Bell's model is incompatible with reality also. You *can* tweak the model so that it's compatible with qm by allowing spacelike separated events to instantaneously interact -- but this is an artificial and misleading way of representing the experimental/observational context and $why/how$ the measurement results are related. So, what's wrong with the model? Well, for one thing, it assumes that rate of coincidental detection is a linear function of $\theta$. But, qm and experiments say otherwise. It's not the combination of the polarization of photon 1 wrt polarizer A and the polarization of photon 2 wrt polarizer B that's being measured in the combined context. Rather, it's the polarization of photon 1 wrt the polarization of photon 2 wrt $\theta$ that's being analyzed. Now, if you assume, as the emission model does, that photon 1 and photon 2 of any given pair of polarizer-incident photons are polarized identically, then how would you formulate the experimental context? Why does the probability of coincidental detection then vary as a nonlinear function of $\theta$? > Not that I think this is a particularly attractive loophole, since > it raises all sorts of questions about how the information would be > stored about which measurement would be made, but I'm still curious > if its technically a loophole. Imo, this particular consideration wrt Bell tests isn't important, that is, no, it's not technically a loophole wrt my understanding of the meaning of Bell's theorem and violations of Bell inequalities. In other words, if paired detection attributes correspond to emission-paired photons (and experimenters do take great care to facilitate this), then Bell inequalities will be experimentally violated because they're based on a model which incorrectly represents the experimental/observational context. My interpretation of the qm formulation is that the spatially separated events don't need to be instantaneously interacting in order to understand nonlinear curves of rate of coincidental detection wrt $\theta$. (see the Law of Malus) However, the consideration of experimental loopholes in general is very valuable insofar as it produces refinements/improvements in experimental techniques.

## Two EPR questions

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no, scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n"Ralph Hartley" &lt;hartley@aic.nrl.navy.mil&gt; schrieb\n&gt; Blake Winter wrote:\n&gt; &gt; Secondly, in considering Bell\'s proof that hidden variable theories\n&gt; &gt; have to be nonlocal, isn\'t there a loophole in the sense that no\n&gt; &gt; matter how one constructs the experiment (even if one uses quantum\n&gt; &gt; processes to choose the polarization measurement orientations) there\n&gt; &gt; would be no way to really get "random" orientations since the theory\n&gt; &gt; is, in fact, deterministic? That is, in some way the initial\n&gt; &gt; conditions which set up the whole experiment would determine what\n&gt; &gt; measurements would be made as well, thereby getting rid of the need\n&gt; &gt; for nonlocal effects. Not that I think this is a particularly\n&gt; &gt; attractive loophole, since it raises all sorts of questions about how\n&gt; &gt; the information would be stored about which measurement would be made,\n&gt; &gt; but I\'m still curious if its technically a loophole.\n&gt;\n&gt; Yes, it is, but it is a very small loophole. I\'ve seen it used by people\n&gt; who obviously had no conception of how *very* small it is.\n&gt;\n&gt; What makes it so small is that Bell\'s theorem is violated for *all*\n&gt; mechanisms for deciding which measurements to make (at least all that have\n&gt; been tried).\n\nI have proposed another argument which works against this loophole:\n\nImagine there is a preferred frame and we learn in some future how to\ncommunicate FTL. You have a working FTL phone - two black boxes\nand some channel between them which allows you to talk with somebody\non Mars without any time delay. Surely, this FTL phone falsifies\nrelativity.\n\nNow imagine some old crank who, despite the obvious falsification\nof relativity, wants to save relativity and presents some arguments which\nsuggest that relativity is not violated.\nYou don\'t really want to be as stupid as that crank? In this case,\nit should be clear that there is something wrong with his arguments.\nThus, any sort of argument which allows to save relativity if there\nexists an FTL phone should be wrong.\n\nNow, the point is that the loophole can be used by that crank too.\nIf there is no free will of the experimenter, you can do whatever\nyou like with your FTL phone but you will be unable to prove\nthat there exists some FTL effects inside the phone.\n\nIlja\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Ralph Hartley" <hartley@aic.nrl.navy.mil> schrieb
> Blake Winter wrote:
> > Secondly, in considering Bell's proof that hidden variable theories
> > have to be nonlocal, isn't there a loophole in the sense that no
> > matter how one constructs the experiment (even if one uses quantum
> > processes to choose the polarization measurement orientations) there
> > would be no way to really get "random" orientations since the theory
> > is, in fact, deterministic? That is, in some way the initial
> > conditions which set up the whole experiment would determine what
> > measurements would be made as well, thereby getting rid of the need
> > for nonlocal effects. Not that I think this is a particularly
> > attractive loophole, since it raises all sorts of questions about how
> > the information would be stored about which measurement would be made,
> > but I'm still curious if its technically a loophole.

>
> Yes, it is, but it is a very small loophole. I've seen it used by people
> who obviously had no conception of how *very* small it is.
>
> What makes it so small is that Bell's theorem is violated for *all*
> mechanisms for deciding which measurements to make (at least all that have
> been tried).

I have proposed another argument which works against this loophole:

Imagine there is a preferred frame and we learn in some future how to
communicate FTL. You have a working FTL phone - two black boxes
and some channel between them which allows you to talk with somebody
on Mars without any time delay. Surely, this FTL phone falsifies
relativity.

Now imagine some old crank who, despite the obvious falsification
of relativity, wants to save relativity and presents some arguments which
suggest that relativity is not violated.
You don't really want to be as stupid as that crank? In this case,
it should be clear that there is something wrong with his arguments.
Thus, any sort of argument which allows to save relativity if there
exists an FTL phone should be wrong.

Now, the point is that the loophole can be used by that crank too.
If there is no free will of the experimenter, you can do whatever
you like with your FTL phone but you will be unable to prove
that there exists some FTL effects inside the phone.

Ilja



Ilja Schmelzer wrote: > I have proposed another argument which works against this loophole > Now, the point is that the loophole can be used by that crank too. I think I have seen your argument before, but didn't read it carefully enough to understand it. It may have been part of a thread I was starting to tune out. > If there is no free will of the experimenter, you can do whatever > you like with your FTL phone but you will be unable to prove > that there exists some FTL effects inside the phone. The problem with that argument is that it uses something like a triple negative and a very unlikely hypothetical, which while logically correct, is more than you can expect the reader to follow. Especially a reader who is already struggling with the concepts, as most of those who need the argument are. A simpler way to put it would be that the loophole could explain away *any* nonlocal effect whatsoever, regardless of any conceivable evidence. Ralph Hartley



It's certainly a rather ridiculous loophole, and I didn't mean to suggest it as being a likely loophole. I was just curious if it was an actual loophole.



"Ilja Schmelzer" writes: >Imagine there is a preferred frame and we learn in some future how to >communicate FTL. You have a working FTL phone - two black boxes >and some channel between them which allows you to talk with somebody >on Mars without any time delay. Surely, this FTL phone falsifies >relativity. >Now imagine some old crank who, despite the obvious falsification >of relativity, wants to save relativity and presents some arguments which >suggest that relativity is not violated. >You don't really want to be as stupid as that crank? In this case, >it should be clear that there is something wrong with his arguments. >Thus, any sort of argument which allows to save relativity if there >exists an FTL phone should be wrong. >Now, the point is that the loophole can be used by that crank too. >If there is no free will of the experimenter, you can do whatever >you like with your FTL phone but you will be unable to prove >that there exists some FTL effects inside the phone. I should mention that the usual utterance produced by those who argue against taking Bell's inequalities seriously, namely the dogmatic assertion that "it is not meaningful" to consider the results of unperformed experiments, such as what would have happened had the magnetic field of the apparatus been aligned differently, is also subject to your objection. This is because anybody can always say that what person B would have heard through the FTL telephone had person A said something different is "undefined", or "not meaningful" or (if they want to summon up some pomposity) "not physically meaningful." The validity of the assertion that the telephone is a device which communicates what A says (whatever that might be) to B can then not be established; only the fact that B heard what A said in this instance can be established. The rejection of so-called counterfactuals is a prescription for never drawing any inferences from observed data, no matter how consistently and reproducibly one event is found to follow another. One would have thought that such a bizarre attitude would be restricted to skeptical philosophers, whose insistence on rigour is so great that any claims to knowledge of an external world are denied. And yet the people who assert that counterfactuals are contraband (the majority of physicists who have managed to get this far in the debate) will at the same time express their disdain for philosophy. (It is, of course, useful for the factory-owner to instill in his workers a certain amount of contempt for those who think compared to those who simply work without thinking. I wonder how many physicists acquired their professed contempt of philosophy from other physicists, rather than having the idea on their own.) R.



"Ralph Hartley" schrieb > Ilja Schmelzer wrote: > > If there is no free will of the experimenter, you can do whatever > > you like with your FTL phone but you will be unable to prove > > that there exists some FTL effects inside the phone. > The problem with that argument is that it uses something like a triple > negative and a very unlikely hypothetical, which while logically correct, > is more than you can expect the reader to follow. Especially a reader who > is already struggling with the concepts, as most of those who need the > argument are. Hm. At the current moment, it is the majority of the scientific community which does not accept my interpretation - that the violation of Bell's inequality is an experimental falsification of Einstein causality, as good as any other falsification. IOW, whose "who need it" are the majority of scientists. I would not expect that this majority is unable to follow a logical argument of this type. > A simpler way to put it would be that the loophole could explain > away *any* nonlocal effect whatsoever, regardless of any > conceivable evidence. Hm. Let's remember why I prefer the FTL variant. The argument is directed against Einstein causality $- my$ claim is that the violation of BE is a falsification of Einstein causality. Now, if an EPRB loophole is sufficient to explain away an FTL phone, Einstein causality becomes obviously unfalsifiable and is, therefore, no longer part of empirical science. Not sure what is simpler. Ilja



schrieb > "Ilja Schmelzer" writes: > > >Imagine there is a preferred frame and we learn in some future how to > >communicate FTL. You have a working FTL phone - two black boxes > >and some channel between them which allows you to talk with somebody > >on Mars without any time delay. Surely, this FTL phone falsifies > >relativity. > > >Now imagine some old crank who, despite the obvious falsification > >of relativity, wants to save relativity and presents some arguments which > >suggest that relativity is not violated. > >You don't really want to be as stupid as that crank? In this case, > >it should be clear that there is something wrong with his arguments. > >Thus, any sort of argument which allows to save relativity if there > >exists an FTL phone should be wrong. > I should mention that the usual utterance produced by those who > argue against taking Bell's inequalities seriously, namely the > dogmatic assertion that "it is not meaningful" to consider the > results of unperformed experiments, such as what would have happened > had the magnetic field of the apparatus been aligned differently, > is also subject to your objection. Thank you for making that point. My FTL phone argument is, indeed, directed against a whole class of arguments around the Bell inequalities. The only arguments I know which fail the test are arguments based on the impossibility to apply the effects for information transfer, and that the inequalities allow two realistic interpretations: An information transfer $A->B$ or an information transfer $B->A$. These two are related. Once we have some effect which can be explained in two ways - as $A->B$ or $B->A -$ then it cannot be used for information transfer: A transfer $A->B$ would be in contra- diction with the explanation $B->A$. What remains is, therefore, a rejection of indirect observation. Observing "$A->B$ or $B->A$" is not accepted, only "$A->B$" pure would be accepted. Such a rejection of indirect observation would be obviously a very serious restriction of the scientific method if applied everywhere. Ilja



Scientists don't accept the Bell inequality violations as a proof against relativity because one can't communicate information using the wave function "collapse". All relativity says is taht information can't be communicated faster than c. Also note that one cannot experimentally tell whether the measurement at A or B was made first - the results are the same either way so there's no meaning to ordering them in time. Furthermore its possible to show that the Bell inequalities are also result from time symmetry. That is, its possible to understand them in a similar way as the Wheeler-Feynman theory of radiation resistance. Under such time symmetry one would expect to get Bell inequalities even from a deterministic classical theory, which leaves quantum physics ok.



"Ilja Schmelzer" writes: > schrieb >> I should mention that the usual utterance produced by those who >> argue against taking Bell's inequalities seriously, namely the >> dogmatic assertion that "it is not meaningful" to consider the >> results of unperformed experiments, such as what would have happened >> had the magnetic field of the apparatus been aligned differently, >> is also subject to your objection. >Thank you for making that point. >My FTL phone argument is, indeed, directed against a whole >class of arguments around the Bell inequalities. >The only arguments I know which fail the test are arguments >based on the impossibility to apply the effects for information >transfer, and that the inequalities allow two realistic interpretations: >An information transfer $A->B$ or an information transfer $B->A$. >These two are related. Once we have some effect which can be >explained in two ways - as $A->B$ or $B->A -$ then it cannot be >used for information transfer: A transfer $A->B$ would be in contra- >diction with the explanation $B->A$. This reaction to the violation of Bell's inequalities is even more common than the objection to counterfactuals. It's still not really a genuine counterargument, though, since nobody ever claimed that the phenomenon could be used to transmit information. It's more of an attitude than an argument - "You can't use this effect to send information, so it's not worth thinking about." If one does think about it a little, though, it quickly becomes apparent that something very strange is indeed going on - there is a conflict between Einstein causality and the observed experimental facts (modulo the very small probability that, as experiments improve, the observed effect will disappear). It means, essentially, that the view of space-time as a structure that constrains which events can affect which other events is incorrect. Space-time can still however be considered as a structure which constrains information flows (since information, rather than influence, is what can not leap across unlimited distances of space to affect the observations of distant observers). The natural question for your ether theory is whether it strictly forbids information from travelling faster than light, since it is evidently comfortable with superluminal influences. >What remains is, therefore, a rejection of indirect observation. >Observing "$A->B$ or $B->A$" is not accepted, only "$A->B$" pure >would be accepted. Such a rejection of indirect observation >would be obviously a very serious restriction of the scientific >method if applied everywhere. I don't believe I've ever heard anybody express that position as their own; that is, a refusal to accept inferences of statements in the form "X or Y" from data which suggests it. Obviously somebody who rejected statements like that would be severely crippled in everyday life, rejecting the inference that x or y must be zero from the observation that xy is zero, for example. On the other hand, the requirement that one's position make sense, or not lead to ridiculous consequences, doesn't appear to be one which many physicists make of themselves when dealing with quantum mechanics. Regards, R.



"Ilja Schmelzer" wrote in message news:... > schrieb > > "Ilja Schmelzer" writes: > > > > >Imagine there is a preferred frame and we learn in some future how to > > >communicate FTL. You have a working FTL phone - two black boxes > > >and some channel between them which allows you to talk with somebody > > >on Mars without any time delay. Surely, this FTL phone falsifies > > >relativity. > > > >Now imagine some old crank who, despite the obvious falsification > > >of relativity, wants to save relativity and presents some arguments which > > >suggest that relativity is not violated. > > >You don't really want to be as stupid as that crank? In this case, > > >it should be clear that there is something wrong with his arguments. > > >Thus, any sort of argument which allows to save relativity if there > > >exists an FTL phone should be wrong. > > > I should mention that the usual utterance produced by those who > > argue against taking Bell's inequalities seriously, namely the > > dogmatic assertion that "it is not meaningful" to consider the > > results of unperformed experiments, such as what would have happened > > had the magnetic field of the apparatus been aligned differently, > > is also subject to your objection. > > Thank you for making that point. > > My FTL phone argument is, indeed, directed against a whole > class of arguments around the Bell inequalities. > > The only arguments I know which fail the test are arguments > based on the impossibility to apply the effects for information > transfer, and that the inequalities allow two realistic interpretations: > An information transfer $A->B$ or an information transfer $B->A$. > > These two are related. Once we have some effect which can be > explained in two ways - as $A->B$ or $B->A -$ then it cannot be > used for information transfer: A transfer $A->B$ would be in contra- > diction with the explanation $B->A$. > > What remains is, therefore, a rejection of indirect observation. > Observing "$A->B$ or $B->A$" is not accepted, only "$A->B$" pure > would be accepted. Such a rejection of indirect observation > would be obviously a very serious restriction of the scientific > method if applied everywhere. In optical Bell tests, in a given coincidence window, the relationship of the polarizations (wrt each other) of two photons from the same oscillator are being analyzed wrt some $\theta$. The relationship between qm predictions,the observed correlation curves (coincidence rates), and Malus' Law seems clear enough. Thus, considerations of an instantaneous effect, $A<->B,$ would seem unnecessary -- and BI has nothing to do with the principle of locality.



blake.winter@houghton.edu (Blake Winter) wrote in message news:<87423d2a.0409261455.69146e11@p...google.com>... > Secondly, in considering Bell's proof that hidden variable theories > have to be nonlocal, isn't there a loophole in the sense that no > matter how one constructs the experiment (even if one uses quantum > processes to choose the polarization measurement orientations) there > would be no way to really get "random" orientations since the theory > is, in fact, deterministic? I think a slightly more serious loophole for the moment is given by the inefficiency of the photon detectors, in that if the hidden variables are allowed to change the detection efficiency per impact (while keeping the average efficiency) you have a loophole until you have an average quantum efficiency, I think, of about 87%. cheers, Patrick.



"Blake Winter" wrote in message news:87423d2a.0410071557.6cbf3170@posting.google.com... > > Scientists don't accept the Bell inequality violations as a proof > against relativity because one can't communicate information using > the wave function "collapse". Actually, that was precisely how Gisin performed some of his experiments. From: ENtanglement, Amir D. Aczel,2002, ISBN $1-55192-549-4$ Page 238: "Gisin believed that while entanglement doesn't allow us to send readable messages faster than light, the phenomenon still violates the 'spirit' of special relativity. He thus wanted to test the entanglement phenomenon within a relativistic framework. In one of his experiments, Gisin used an absorbing black surface, placed at the ends of the optical fiber, to collapse the wave function. [.....] This complex experiment using moving reference frames resulted in a strong confirmation of nonlocal entanglement and the prediction of QM." Regards Joe "We won in Iraq. Now we have our very own West Bank." --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6..774 / Virus Database: 521 - Release Date: $10/7/04$



schrieb > "Ilja Schmelzer" writes: > >These two are related. Once we have some effect which can be > >explained in two ways - as $A->B$ or $B->A -$ then it cannot be > >used for information transfer: A transfer $A->B$ would be in contra- > >diction with the explanation $B->A$. > > This reaction to the violation of Bell's inequalities is even more > common than the objection to counterfactuals. It's still not really > a genuine counterargument, though, since nobody ever claimed that > the phenomenon could be used to transmit information. It's more > of an attitude than an argument - "You can't use this effect to send > information, so it's not worth thinking about." Yep. > If one does think about it a little, though, it quickly becomes > apparent that something very strange is indeed going on - there is > a conflict between Einstein causality and the observed experimental > facts (modulo the very small probability that, as experiments improve, > the observed effect will disappear). Yep. Except that I don't see a reason to name this "strange". That's what happens all the time in science - theories are falsified by experiments. Moreover, we have alternative theories which are not falsified (Bohmian mechanics). What's strange? The only strange thing is the reaction of the scientific community which prefers to reject realism instead of accepting the facts. Unfortunately, as you say: > On the other hand, the requirement that one's position make sense, > or not lead to ridiculous consequences, doesn't appear to be one > which many physicists make of themselves when dealing with quantum > mechanics. ------------------------------------ > It means, essentially, that > the view of space-time as a structure that constrains which events > can affect which other events is incorrect. Space-time can still > however be considered as a structure which constrains information > flows (since information, rather than influence, is what can not > leap across unlimited distances of space to affect the observations > of distant observers). > > The natural question for your ether theory is whether it strictly > forbids information from travelling faster than light, since it > is evidently comfortable with superluminal influences. In the case of my classical ether theory I have proven the EEP. See http://www.arxiv.org/abs/gr-qc/0205035. Once the theory is classical, causal and deterministic, it follows from the EEP that the light cone restricts information transfer. In the pure quantum case we have no longer a classical light cone which allows to restrict the flow of information. Therefore in full quantum theory we should not expect such a restriction. The open question is, therefore, one about the semiclassical limit where density, velocity and pressure of the ether are considered as classical fields but the other degrees of freedom as quantum fields. I don't think this will be a serious problem. Ilja



NNTP-Posting-Host: lfa222122.richmond.edu X-Trace: rumor.richmond.edu 1097485444 8872 141.166.222.122 (11 Oct 2004 09:04:04 GMT) X-Complaints-To: usenet@rumor.richmond.edu NNTP-Posting-Date: Mon, 11 Oct 2004 09:04:04 $+0000$ (UTC) Xref: core-easynews sci.physics.research:59806 "Blake Winter" schrieb > Scientists don't accept the Bell inequality violations as a proof > against relativity because one can't communicate information using the > wave function "collapse". This is something I have a problem with. I provide arguments against this position, but these arguments are simply ignored. > All relativity says is that information > can't be communicated faster than c. That is a positivistic reduction of relativity. It should be distinguished from a fundamental claim about reality. The problem with such reductions is that people like to switch between different versions. If confronted with the violation of Bell's inequality, they move to the positivistic version. The positivistic version is compatible with Bohmian mechanics, which has a hidden preferred frame. But relativists like to reject Bohmian mechanics because it has a preferred frame, using the other interpretation of relativity. > Also note that one cannot > experimentally tell whether the measurement at A or B was made first - > the results are the same either way so there's no meaning to ordering > them in time. I have already spend some postings in this thread "noting" this difference. We observe "$A->B$ or $B->A$". Above explanations violate Einstein causality. If you would like to reject indirect observation as a way of falsification, you should throw away a lot of science. Interesting what remains at all. > Furthermore its possible to show that the Bell inequalities are also > result from time symmetry. That is, its possible to understand them > in a similar way as the Wheeler-Feynman theory of radiation > resistance. Under such time symmetry one would expect to get Bell > inequalities even from a deterministic classical theory, which leaves > quantum physics ok. Of course you can give up causality at all, allow causal influences backward in time in some time-symmetric way. That's another nice example of an "explanation" which allows to explain away even a working FLT phone (see my previous postings in this thread). Ilja



"Thomas Trotter" schrieb > "Ilja Schmelzer" wrote > > My FTL phone argument is, indeed, directed against a whole > > class of arguments around the Bell inequalities. > > > > The only arguments I know which fail the test are arguments > > based on the impossibility to apply the effects for information > > transfer, and that the inequalities allow two realistic interpretations: > > An information transfer $A->B$ or an information transfer $B->A$. > > > > These two are related. Once we have some effect which can be > > explained in two ways - as $A->B$ or $B->A -$ then it cannot be > > used for information transfer: A transfer $A->B$ would be in contra- > > diction with the explanation $B->A$. > > > > What remains is, therefore, a rejection of indirect observation. > > Observing "$A->B$ or $B->A$" is not accepted, only "$A->B$" pure > > would be accepted. Such a rejection of indirect observation > > would be obviously a very serious restriction of the scientific > > method if applied everywhere. > > In optical Bell tests, in a given coincidence > window, the relationship of the polarizations > (wrt each other) of two photons from the same > oscillator are being analyzed wrt some $\theta$. > > The relationship between qm predictions,the > observed correlation curves (coincidence rates), > and Malus' Law seems clear enough. > > Thus, considerations of an instantaneous effect, > $A<->B,$ would seem unnecessary -- and BI has > nothing to do with the principle of locality. I don't understand your point. In case you refer to known loopholes of actual tests (like detector efficiency): That's nothing I care about. But that does not seem to be your point. It sounds more like "we can compute the observed probabilities with QM, so what?" The point is that QM is not a realistic theory, it does not describe what really happens, it allows to compute only some probabilities without explaining them. But there is no necessity to reject classical realism, realistic theories which are compatible with observation exist (Bohmian mechanics). Of course, as long as BM has not been known, it was a reasonable decision to "shut up and calculate" without thinking too much about the foundations: There were a lot of things to compute with QM, a lot of things which could be done in this way. But today? It is also possible to understand that Einstein did not like BM. Last not least it requires a preferred frame. But Einstein has not known Bell's inequality and Aspect's experiment. But today? Ilja