What are the implications of this experiment?

[Varon]

Here's the reason why ontology is very important. And one can follow it by logic. We know qualia or internal subjective experience is not part of our physics as Demystifier has emphasized before. So how is qualia related to matter (our brain). The right interpretation would offer the interface of how qualia is coupled to brain! This is so because matter is described by quantum mechanics. What controls matter, the wave function. Therefore the right interpretation would offer solution to how qualia is related to the wave function which describes matter. Get it? If you can see logical flaw in this argument, pls justify your counter arguments (including you Demystifer... if you can offer arguments that qualia is related to spacetime and not to matter, then pls. explain why you think it is so). If you or anyone can convince me qualia is not related to quantum mechanics. Then pls. do so and I'm outta here. I already spent 8 years trying to understand all this and frustrated the answers are so far away. But know that either by quantum or spacetime or by hooks and by crooks, we will arrive at the real physics of qualia.

 

[ZapperZ]

Where is the original research article, rather than just internet sites jaw-boning about it third hand--like this one?

https://www.physicsforums.com/showpost.php?p=3336459&postcount=136

Zz.

 

[Demystifier]

Varon, there is serious logical flaw in your argument, but it would be too much off topic to discuss it here. You may open a new thread on it. If the authorities move it to the Philosophy forum, inform me by PM about your thread and I will respond there.

 

[ZapperZ]

Varon, there is serious logical flaw in your argument, but it would be too much off topic to discuss it here. You may open a new thread on it. If the authorities move it to the Philosophy forum, inform me by PM about your thread and I will respond there.

This thread cannot be moved to the Philosophy forum because most of it are on a physics discussion of the experiment. Those who wish to continue that this new line of discussion should open a new thread there, with the caveat that it MUST follow the Guidelines set by the Philosophy forum.

Zz.

 

[Varon]

Ok Zapper. Now on topic.

http://www.sciencemag.org/content/332/6034/1170.full

Has anyone tried purchasing the article? How much is it? Do you think it would end up in arxiv sometime soon? In the past there was this Asfar (what's the correct spelling?) paper about wave and particle being displayed at the same time.. but it's controversial. I wonder if this would end up like it. How many here believe Asfar indeed show particle and wave can appear at the same time versus it's just some kind of misconception?

 

[Demystifier]

Has anyone tried purchasing the article? How much is it?

I see the paper automatically, because my institution pays for it. I don't know how much.

 

[Varon]

Varon, there is serious logical flaw in your argument, but it would be too much off topic to discuss it here. You may open a new thread on it. If the authorities move it to the Philosophy forum, inform me by PM about your thread and I will respond there.

Done. https://www.physicsforums.com/showthread.php?t=505217

 

[Demystifier]

In the past there was this Asfar (what's the correct spelling?) paper about wave and particle being displayed at the same time.. but it's controversial. I wonder if this would end up like it. How many here believe Asfar indeed show particle and wave can appear at the same time versus it's just some kind of misconception?

I have no idea what Asfar experiment is, but I have no doubts that all future experiments will only reinforce the validity of the experiment we discuss here. That's because this experiment has a strong theoretical basis, as we discussed here:
https://www.physicsforums.com/showthread.php?t=252491

 

[SpectraCat]

Also note that the correct interpretation would produce an emergence that won't be found in the incorrect interpretations. It's like the correct understanding of atomic theory has led to superconductivity.

*sigh* wrong again ... superconductivity is an experimental phenomenon that pre-dates QM. Kamerlingh-Onnes discovered it in 1911.

 

[Varon]

I have no idea what Asfar experiment is, but I have no doubts that all future experiments will only reinforce the validity of the experiment we discuss here. That's because this experiment has a strong theoretical basis, as we discussed here:
https://www.physicsforums.com/showthread.php?t=252491

Oh. Spelling is Afshar. His experiment tried to prove that wave and particle can be made to manifest at the same time contrary to the principle of complementary just like the new experiment of this thread. Anyway. What do you think of Afshar? Won't this new experiment end up like it, full of controversy?

http://en.wikipedia.org/wiki/Afshar_experiment

"Afshar's conclusion is that the light exhibits wave-like behavior when going past the wires, since the light goes through the spaces between the wires, but avoids the wires themselves, when both slits were open, but also exhibits particle-like behavior after going through the lens, with photons going to a given photo-detector. Afshar argues that this behavior contradicts the principle of complementarity since it shows both complementary wave and particle characteristics in the same experiment for the same photons."

 

[Varon]

*sigh* wrong again ... superconductivity is an experimental phenomenon that pre-dates QM. Kamerlingh-Onnes discovered it in 1911.

But the BCS model was discovered after QM. Because without understanding wave function, the dance of the cooper pairs can never be understood.

 

[ZapperZ]

Oh. Spelling is Afshar. His experiment tried to prove that wave and particle can be made to manifest at the same time contrary to the principle of complementary just like the new experiment of this thread.

Er... where did this new experiment claimed such a thing? You DO know that the supposed "path" that is being measured was deduced from the AVERAGE momentum measured at that location, don't you?

Considering that, from your post, that you haven't read the actual paper, do you think it is wise for you to make claims about what it says?

Zz.

 

[Demystifier]

Oh. Spelling is Afshar. His experiment tried to prove that wave and particle can be made to manifest at the same time contrary to the principle of complementary just like the new experiment of this thread. Anyway. What do you think of Afshar? Won't this new experiment end up like it, full of controversy?

http://en.wikipedia.org/wiki/Afshar_experiment

The source of controversy is the Afshar's claim that his experiment contradicts the principle of complementarity. By contrast, the authors of the paper we discuss here are too clever to make a similar statement for their experiment. By avoiding such a statement, they avoid the controversy as well.

 

[Varon]

The source of controversy is the Afshar's claim that his experiment contradicts the principle of complementarity. By contrast, the authors of the paper we discuss here are too clever to make a similar statement for their experiment. By avoiding such a statement, they avoid the controversy as well.

Nearly 80 years ago Bohr concluded that in the absence of measurement to determine its position, a particle has no position. What can you say about the latest experiment with regards to Bohr statement? I wonder if it is possible a single particle has no position, but a barrage of them can manifest positions even when unmeasured. This is one way to make compatible Bohr interpretation with the latest experiment (if it holds). Let me know how else to think of it.

 

[SpectraCat]

But the BCS model was discovered after QM. Because without understanding wave function, the dance of the cooper pairs can never be understood.

Cooper pairs only have to do with the understanding of superconductivity, not the phenomenon itself. You said:

It's like the correct understanding of atomic theory has led to superconductivity.

and

Superconductivity is an emergence.

That certainly implies that you think that the phenomenon of superconductivity is somehow "an emergence" (whatever that means). That is what I was responding to, and it is clearly wrong, since superconductivity was discovered long before BCS theory was developed. Are you claiming that a theory to explain a known experimental phenomenon is somehow "emergence"? That which certainly seems contradictory to the other definitions of emergence that you have given elsewhere, as well as the normal usage of emergence in the philosophical sense. How is the theoretical explanation of the known experimental phenomenon superconductivity, any different than the theoretical explanation of any other known physical phenomenon?

 

[f95toli]

Nearly 80 years ago Bohr concluded that in the absence of measurement to determine its position, a particle has no position. What can you say about the latest experiment with regards to Bohr statement? I wonder if it is possible a single particle has no position, but a barrage of them can manifest positions even when unmeasured. This is one way to make compatible Bohr interpretation with the latest experiment (if it holds). Let me know how else to think of it.

But again, you seem to think that this experiment tells us something profound about QM, that we did not already now. The experiment does not tell you anything about "which path" for a single particle,
Weak measurements are nothing new, and there are plenty of related experiments that have tested things like the relation between T2 and information loss etc.
So again, this is a nice experiment but it agrees with standard QM and is independent of interpretation.

 

[Fyzix]

Varon, PLEASE just stop!
We understand you are curious, but if you continue to spew contradicting ******** in every other post, someone will have to ban you.

One day you buy 10 books about MWI, talk about sniping Obama in another universe and wanting to merge with this image completely.

The next day your in a post talking about "there is no particle, no wave, just a probability cloud"

Then it's this god damn Neumaier interpretation.
If his interpretation is so good, why the hell isn't ANYONE talking about it?
You realize that people come up with pet theories 24/7 that never amount to anything right?
Just because he has managed to convince you, doesn't mean it's right, because let's be honest here, you pretty much believe ANYTHING.

Also please, stop reading a wikipedia article half way through, then come here and critize people for not knowing what you think you just understood from reading 3minutes about something...

Being curios and asking question is good, it's what science is about, but you are frankly just ignorant and annoying at this point.
If you want to understand QM and the measurement problem, read about each interpretation and it's problems, then conclude for your self.

 

[Demystifier]

Nearly 80 years ago Bohr concluded that in the absence of measurement to determine its position, a particle has no position. What can you say about the latest experiment with regards to Bohr statement? I wonder if it is possible a single particle has no position, but a barrage of them can manifest positions even when unmeasured. This is one way to make compatible Bohr interpretation with the latest experiment (if it holds). Let me know how else to think of it.

Yes, the experiment is compatible with the Bohr interpretation, and this is roughly how it can be thought of.

 

[Varon]

Varon, PLEASE just stop!
We understand you are curious, but if you continue to spew contradicting ******** in every other post, someone will have to ban you.

One day you buy 10 books about MWI, talk about sniping Obama in another universe and wanting to merge with this image completely.

The next day your in a post talking about "there is no particle, no wave, just a probability cloud"

Then it's this god damn Neumaier interpretation.
If his interpretation is so good, why the hell isn't ANYONE talking about it?
You realize that people come up with pet theories 24/7 that never amount to anything right?
Just because he has managed to convince you, doesn't mean it's right, because let's be honest here, you pretty much believe ANYTHING.

Also please, stop reading a wikipedia article half way through, then come here and critize people for not knowing what you think you just understood from reading 3minutes about something...

Being curios and asking question is good, it's what science is about, but you are frankly just ignorant and annoying at this point.
If you want to understand QM and the measurement problem, read about each interpretation and it's problems, then conclude for your self.

I already mentioned that on a monday I'm a Many Worlder, on a tuesday, I'm a follower of Neumaier, on a wednesday, I'm a Bohmian, on a thursday, A Copenhagenist, on a friday, A follower of Objective Collapse, on a saturday, other interpretations, on a sunday, pure QM dumb down shut up and calculate Statistical Interpretation. This it one way to get unbiased. Yes. I'm quite ignorant. Anyway. I'll sleep now. It's nightime in my place. Tomorrow. I'll hold no interpretation to give you spaces. Anyway. Continue your discussions. I'm just attracted to this thread "What are the implications of this experiment?" because I thought it is some kind of breakthrough (akin to discovery of the Higgs) and pretty excited.

 

[Demystifier]

I already mentioned that on a monday I'm a Many Worlder, on a tuesday, I'm a follower of Neumaier, on a wednesday, I'm a Bohmian, on a thursday, A Copenhagenist, on a friday, A follower of Objective Collapse, on a saturday, other interpretations, on a sunday, pure QM dumb down shut up and calculate Statistical Interpretation. This it one way to get unbiased.

I love it.

 

[yoda jedi]

from the creator of weak measurements (Yakir Aharonov):

http://www.tau.ac.il/~yakir/yahp/yh30

..."A description of quantum systems at the time interval between two successive measurements is presented. Two wave functions, the first preselected by the initial measurement and the second post-selected by the final measurement describe quantum systems at a single time"...http://www.aps.org/units/gqi/newsletters/upload/fall09.PDF

..."The "keynote" speaker -- and certainly the most renowned – was Yakir Aharanov [ChapmanUniversity]. Armed with only a pen, he gave a very nice derivation of his two-state formalism for postselected systems, and then discussed the intriguing aspects of "weak measurements" that can be performed on ensembles of such systems at intermediate times between the (strong) pre- and post- selections. If the "strength" of the weak measurement is weighted by some parameter a << 1, then the information one gains from the weak measurement scales as "a", but the net effect from the weak measurement on the intermediate quantum state scales like "a2". Aharanov concluded that for sufficiently weak measurements one could experimentally determine what was actually happening in a quantum system without disturbing it (given a large enough ensemble). From this perspective the "ontic" state would be best described by two wavefunctions; a "history vector" determined by the initial pre-selection as well as a "destiny vector" determined by the final post-selection. Ken Wharton's talk extended such a two-state formalism into the
relativistic domain, outlining a candidate psi-epistemic model in which a two-component classical field was constrained by two-time boundary conditions (corresponding to a preparation and a measurement).

Perhaps the first step in good science is to dispel mysticism. deBB theory dispels the mysticism of the observer's special position in the Copenhagen interpretation. The Copernican Principle holds. Ding dong, the witch is dead.

As usual, the above is my own humble opinion. Feel free to correct me if I have made a mistake.

well said.

.

 

[SpectraCat]

Aharanov concluded that for sufficiently weak measurements one could experimentally determine what was actually happening in a quantum system without disturbing it (given a large enough ensemble).

So what has changed? The weaker a measurement is, the less specific the information obtained can be about a given particle, so you need lots of statistics to build up the answer. Didn't we already know that? Surely the weakest measurement possible is no measurement at all ... in such a case you need to do an ensemble average to learn about the full probability distribution. I have never understood the emphasis on weak measurements as somehow refuting the CI ... as far as I can tell they are completely consistent with it.

 

[yoda jedi]

So what has changed? The weaker a measurement is, the less specific the information obtained can be about a given particle, so you need lots of statistics to build up the answer. Didn't we already know that? Surely the weakest measurement possible is no measurement at all ... in such a case you need to do an ensemble average to learn about the full probability distribution. I have never understood the emphasis on weak measurements as somehow refuting the CI ... as far as I can tell they are completely consistent with it.

are you furious ?

i don't like red letters...

...lol...

 

[SpectraCat]

are you furious ?

i don't like red letters...

...lol...

Sorry about the red letters ... but to me, that was the most important part of that comment, and you left it out of your original bold statement, so I wanted to give it extra emphasis in my post .

No, I am not furious ... just emphatic.

 

[yoda jedi]

Sorry about the red letters ... but to me, that was the most important part of that comment, and you left it out of your original bold statement, so I wanted to give it extra emphasis in my post .

No, I am not furious ... just emphatic.

nitpicking cos i posted it complete, re-read again...

if you like, all bolded...

.."The "keynote" speaker -- and certainly the most renowned – was Yakir Aharanov [ChapmanUniversity]. Armed with only a pen, he gave a very nice derivation of his two-state formalism for postselected systems, and then discussed the intriguing aspects of "weak measurements" that can be performed on ensembles of such systems at intermediate times between the (strong) pre- and post- selections. If the "strength" of the weak measurement is weighted by some parameter a << 1, then the information one gains from the weak measurement scales as "a", but the net effect from the weak measurement on the intermediate quantum state scales like "a2". Aharanov concluded that for sufficiently weak measurements one could experimentally determine what was actually happening in a quantum system without disturbing it (given a large enough ensemble). From this perspective the "ontic" state would be best described by two wavefunctions; a "history vector" determined by the initial pre-selection as well as a "destiny vector" determined by the final post-selection. Ken Wharton's talk extended such a two-state formalism into the relativistic domain, outlining a candidate psi-epistemic model in which a two-component classical field was constrained by two-time boundary conditions (corresponding to a preparation and a measurement)"......lol...
.

 

[SpectraCat]

nitpicking cos i posted it complete, re-read again...

if you like, all bolded...

.."The "keynote" speaker -- and certainly the most renowned – was Yakir Aharanov [ChapmanUniversity]. Armed with only a pen, he gave a very nice derivation of his two-state formalism for postselected systems, and then discussed the intriguing aspects of "weak measurements" that can be performed on ensembles of such systems at intermediate times between the (strong) pre- and post- selections. If the "strength" of the weak measurement is weighted by some parameter a << 1, then the information one gains from the weak measurement scales as "a", but the net effect from the weak measurement on the intermediate quantum state scales like "a2". Aharanov concluded that for sufficiently weak measurements one could experimentally determine what was actually happening in a quantum system without disturbing it (given a large enough ensemble). From this perspective the "ontic" state would be best described by two wavefunctions; a "history vector" determined by the initial pre-selection as well as a "destiny vector" determined by the final post-selection. Ken Wharton's talk extended such a two-state formalism into the relativistic domain, outlining a candidate psi-epistemic model in which a two-component classical field was constrained by two-time boundary conditions (corresponding to a preparation and a measurement)"......lol...

.

Ok .. fine. Are you going to address my comments from that post, or are you only concerned with my formatting?

 

[yoda jedi]

Ok .. fine. Are you going to address my comments from that post, or are you only concerned with my formatting?

your comments are your comments, your point of view, just that.

I respect them, but I do not share them...


.

 

[IllyaKuryakin]

LOL, sometimes my two cats fight, but they really love each other. It's not as entertaining as watching scientists fight though. My cats don't throw philosophy and formulas at each other like the food fight scene from Animal House.

So, what do we know to be a fact? Someone much smarter than I said something to the effect that the central mystery of Quantum Physics, the only mystery, is contained in the double slit experiment, so we will take that as an axiom.

Yakir Aharonov said we can gather just a little information about a trajectory of a particle path and have a very very much smaller affect on the quantum system or state, so that in theory it is possible to gather enough information from a large ensemble of particles to calculate average trajectories of particles and see what is happening in the double slit experiment, without destroying the interference pattern.

Steinberg, et al, from the University of Toronto, preformed that experiment elegantly with some very sophisticated equipment and indeed found the average trajectories of particles followed deBB theory almost perfectly.

Statistical Quantum Theory is a 100% correct statistical (indeterministic) method of performing Quantum Mechanics. It is a good tool for doing some jobs, like designing a quantum computer, but it tells us very little about the physical processes occurring in the double slit experiment. It provides the right answer every time, but it doesn't provide a physical model of what is happening.

deBB theory produces the same correct answer, but in a deterministic fashion that generates a physical model of the process, i.e., the guiding wave goes through both slits, creating the interference pattern, and the particle goes through one or the other of the slits, but follows the guiding wave to it's destination, reflecting the interference pattern of the guiding wave.

If there was any way on this Earth to explain the wave-particle duality without needing both a wave and a particle working in conjunction, I'd say, design an experiment to test it. But to my knowledge, the only deterministic explanation that has ever been experimentally verified is deBB theory.

So, just as we have deterministic classical mechanics which provides a physical model of the process involved, and non-deterministic statistical classical mechanics which can more easily solve some problems, but does not provide a physical model other than the math process, we now have statistical QM (orthodox QM) which provides the correct answers but no physical model, and deterministic deBB Theory which provides the same results, but describes a physical model as well.

But given this model, i.e., that a photon consists of a corpuscular particle and a guiding wave moving in conjunction, certainly there are additional experiments that can be performed that will tell us more about this conjunction? Does the wave lead the particle? If not, how does the particle follow the wave? Obviously they are separate, since the wave splits and goes through both slits, but the particle only goes through one or the other, so by what force or field does the wave redirect the trajectory of the particle to form the interference pattern?

Having a deterministic physical model is what physics is all about. It allows us to not only come up with the correct results in an engineering sense, but to also understand the physical processes and ask deeper questions about the nature of the Universe. Perhaps 100 years hence we will look back and laugh at how little we understood about a simple little photon today. In the meantime, I'd suggest we set prejudices aside, keep the philosophical food fights to a minimum, and allow rock solid theory, math, and experimentation to guide us out of this long dark tunnel.

Having a physical model is a wonderful thing! Be Happy!

 

[Phrak]

http://www.sciencemag.org/content/332/6034/1170.full

Thanks. For 15 bucks I can buy it.

Weak measurements are pivitol elements to my own research. But so are a lot of other things, so I haven't given them just research time, it seems.

I'm sure this article, for many Bohmian supporters, obtains some vindication. However, for myself, I don't find the appearance of Bhomian-like trajectory plots in support the notion that quantization should involve tiny billiard-ball-like obects following definite trajectories that convincing.

I don't think that quantum physicists, as a whole, have sufficiently internalized the notion that their theories can be sufficiently correct without formulations that are not inconsistant with spacetime, not as a flat Lorenzian sheet, but requiring correctness on the inclusion of curvature.

It is not that specualative formulations cannot be 'good enough' in many cases, but can still be inconsistant with the nature of spacetime as we know it. Where are the attempts at formulating coordinate indepedent quantum mechanics?

Second on this list is the deficiency in the internalization of 'causality and determinism'. Where did this stuff come from and why is it a part of science? These unending and weakly solidified notions are better left to the philosophers. Rather, the focus should be on the consistency of the stuff hypothesized to exist on some given spacelike hypersurface to be consistent with the stuff on another non-intersecting hypersurface.

 

[Varon]

I'm not sure about the Neumaier interpretation, but your explanation of the Neumaier interpretation certainly does not make sense at all. For example, if there is only field that goes through both slits and nothing else, and if there is no collapse, then why on the screen we see localized objects?

Just saw this message. You obviously never taken attention to it previously or you could see the explanation stated already. This interpretation is completely opposite to Bohmian Mechanics so take special note of it. So if only field that goes through both slits and nothing else and if there is no colapse, then you asked why on the screen we see localized objects. Well. He explained that in detectors. There are millions of existing electrons as they are part of detection event. When one of these is triggered randomly, all the energies goes to that one electron triggered. And we erronously think it is the same particle sent from the emitter when it is not. Even when buckyball is sent. Still electrons are detected. Not buckyball. Therefore try to propose experiments where buckyball is indeed seen at the detector. If this experiment proves buckyball is localized at the detector.. then many points to Bohmian Mechanics and negative points to QFT Interpretation (Emphased by Neumaier).

Now let's go to the topic of this thread... about Weak measurement. I can't understand it fully as I don't have the full paper. You said that it didn't falsify Bohr declaration that in the absense of measurement to determine its position, a particle has no position. Yet particle paths or trajectories can be detected. Using the simplest words, how exactly are the trajectories detected. Did they see many particle stream passing either left or right slits? If so, it shows particle have positions even before measurement.. because without positions, no trajectories should be seen. So why didn't it invalidate Bohr statement? It may not tell if a single particle has position or not. But it has detected an ensemble of positions.. which means.. there is at least position! Well?

 

[SpectraCat]

LOL, sometimes my two cats fight, but they really love each other. It's not as entertaining as watching scientists fight though. My cats don't throw philosophy and formulas at each other like the food fight scene from Animal House.

So, what do we know to be a fact? Someone much smarter than I said something to the effect that the central mystery of Quantum Physics, the only mystery, is contained in the double slit experiment, so we will take that as an axiom.

Yakir Aharonov said we can gather just a little information about a trajectory of a particle path and have a very very much smaller affect on the quantum system or state, so that in theory it is possible to gather enough information from a large ensemble of particles to calculate average trajectories of particles and see what is happening in the double slit experiment, without destroying the interference pattern.

Steinberg, et al, from the University of Toronto, preformed that experiment elegantly with some very sophisticated equipment and indeed found the average trajectories of particles followed deBB theory almost perfectly.

Statistical Quantum Theory is a 100% correct statistical (indeterministic) method of performing Quantum Mechanics. It is a good tool for doing some jobs, like designing a quantum computer, but it tells us very little about the physical processes occurring in the double slit experiment. It provides the right answer every time, but it doesn't provide a physical model of what is happening.

deBB theory produces the same correct answer, but in a deterministic fashion that generates a physical model of the process, i.e., the guiding wave goes through both slits, creating the interference pattern, and the particle goes through one or the other of the slits, but follows the guiding wave to it's destination, reflecting the interference pattern of the guiding wave.

If there was any way on this Earth to explain the wave-particle duality without needing both a wave and a particle working in conjunction, I'd say, design an experiment to test it. But to my knowledge, the only deterministic explanation that has ever been experimentally verified is deBB theory.

So, just as we have deterministic classical mechanics which provides a physical model of the process involved, and non-deterministic statistical classical mechanics which can more easily solve some problems, but does not provide a physical model other than the math process, we now have statistical QM (orthodox QM) which provides the correct answers but no physical model, and deterministic deBB Theory which provides the same results, but describes a physical model as well.

But given this model, i.e., that a photon consists of a corpuscular particle and a guiding wave moving in conjunction, certainly there are additional experiments that can be performed that will tell us more about this conjunction? Does the wave lead the particle? If not, how does the particle follow the wave? Obviously they are separate, since the wave splits and goes through both slits, but the particle only goes through one or the other, so by what force or field does the wave redirect the trajectory of the particle to form the interference pattern?

Having a deterministic physical model is what physics is all about. It allows us to not only come up with the correct results in an engineering sense, but to also understand the physical processes and ask deeper questions about the nature of the Universe. Perhaps 100 years hence we will look back and laugh at how little we understood about a simple little photon today. In the meantime, I'd suggest we set prejudices aside, keep the philosophical food fights to a minimum, and allow rock solid theory, math, and experimentation to guide us out of this long dark tunnel.

Having a physical model is a wonderful thing! Be Happy!

I guess everyone sees what they want to .. you and yoda apparently see evidence to support the formulation of Bohmian mechanics. I do not see that, and do not understand why you see it. In Bohmian mechanics, the pilot waves are not observable, only the particles are observable, right? Bohmian mechanics predicts that the pilot wave defines the probabilistically weighted set of possible trajectories allowed for the particle, but that any single particle only follows one trajectory, right? So that notion can only be definitively demonstrated by observing individual trajectories for individual particles, which has not been realized.

With regard to the CI, it predicts that the wavefunction defines a probability amplitude for finding the particle anywhere in space. The wavefunction propagates through both slits at once, which gives rise to the interference effect. So, the *average* trajectory for the particles through the slits can be obtained simply by solving for $|\Psi^2|$ at every point in space.

This latest experiment uses weak measurements to reveal the *average* trajectories of a large ensemble of particles. From what I can tell, that result is completely consistent with both dBB and CI. I am not as familiar with MWI, but I imagine they are fine too.

Thus, while the result is a spectacular experimental tour de force, I do not see how it sheds light on any foundational issues in QM.

 

[Varon]

I guess everyone sees what they want to .. you and yoda apparently see evidence to support the formulation of Bohmian mechanics. I do not see that, and do not understand why you see it. In Bohmian mechanics, the pilot waves are not observable, only the particles are observable, right? Bohmian mechanics predicts that the pilot wave defines the probabilistically weighted set of possible trajectories allowed for the particle, but that any single particle only follows one trajectory, right? So that notion can only be definitively demonstrated by observing individual trajectories for individual particles, which has not been realized.

With regard to the CI, it predicts that the wavefunction defines a probability amplitude for finding the particle anywhere in space. The wavefunction propagates through both slits at once, which gives rise to the interference effect. So, the *average* trajectory for the particles through the slits can be obtained simply by solving for $|\Psi^2|$ at every point in space.

This latest experiment uses weak measurements to reveal the *average* trajectories of a large ensemble of particles. From what I can tell, that result is completely consistent with both dBB and CI. I am not as familiar with MWI, but I imagine they are fine too.

Thus, while the result is a spectacular experimental tour de force, I do not see how it sheds light on any foundational issues in QM.

So even if a particle has really no position before measurement as Bohr emphasized. Weak measurement means that just like detector screen measuring the particles. Space path itself somehow serve as the detector to measure the particles? This means even if a particle has really no position, the weak measurement somehow precipitate the particles path that shouldn't have been there at all without this weak measurement attempt?

 

[IllyaKuryakin]

Second on this list is the deficiency in the internalization of 'causality and determinism'. Where did this stuff come from and why is it a part of science? These unending and weakly solidified notions are better left to the philosophers.

Please allow me to address the second item on your list first. I believe causality to be an essential ingredient of science. All science to date includes the pre-requisite of causality, with the recent notable exception of the now self-repudiated Steven Hawkins claim to destruction of information in a black hole. While you can claim that causality is simply a "notion" and not a necessary condition of science, I would beg to differ, citing every bit of science done in the history of mankind. In my limited understanding of the scientific method, causality is a necessary condition in the discrimination between science and mysticism. While I'm willing to consider science without causality when it comes from someone as expert in her or his field as Steven Hawking and black holes, I'm not ready to abandon causality as a necessary condition of any and all science, at least not yet.

Determinism is a completely different situation, in my view. In some sense it is just a "notion", that is not a necessary requirement for science. I cite all the good work done in the field of classical statistical mechanics and orthodox statistical quantum mechanics. In my opinion, determinism has the advantage of providing a model of a physical system that can be tested and refined by experiment. While not always required to reach the correct result of cause and effect, determinism has led to significant advances in most fields of science. I'm certainly willing to accept indeterministic solutions to physical problems, but given the option of equivalent solutions to a physical problem, I would prefer the deterministic solution due to its facility for development and refinement through experimentation. This is because I see experimentation as another essential ingredient of science. So while determinism is not a necessary condition for experimentation (which is a necessary ingredient of the scientific method), it provides a solid foundation for experimental confirmation and development. Of course, that's just my opinion.

 

[Demystifier]

When one of these is triggered randomly, all the energies goes to that one electron triggered.

And why precisely this happens? And if all energy from the field goes to that one little electron, isn't it a kind of collapse of the field?

 

[Demystifier]

Now let's go to the topic of this thread... about Weak measurement. I can't understand it fully as I don't have the full paper.

You certainly can download the theoretical papers I mentioned in the first post in
https://www.physicsforums.com/showthread.php?t=252491
which should answer most of your questions, even better than the experimental paper you don't have.