Mind over matter reality or myth?

[quarknsoul]

I think brain waves probably disturbed the wave function. Human's brain can make electromagnetic field, do you think?

 

[bhobba]

I think brain waves probably disturbed the wave function. Human's brain can make electromagnetic field, do you think?

Then you think wrong. The EM field of the brain can't do that. It happens whether a human being is there or not.

Thanks
Bill

 

[Mark Harder]

You've got me curious. Care to start a thread about it? I bet it is those experiments where they record sound on a boundary. They then reproduce that sound at the boundary, inverting the wave and focusing the energy at the original source.

No, I don't think the boundary story to which you refer is included. As I recall there are a couple of demos using white powder to indicate nodes on vibrating surfaces. In one of these, they used a violin bow to show how patterns of vibrational nodes change with changes in sound intensity. There are also demos of electrically stimulated plates doing the same thing. Maybe that's what you mean. There are also videos of small objects suspended in 3D nodes in a body of air.

 

[adfreeman]

Then you think wrong. The EM field of the brain can't do that. It happens whether a human being is there or not.

Thanks
Bill

I've been reading and watching documentaries about Bell's inequality and the Aspect experiments, and I have the hunch that at least one of the experiments might have to do with what happens in the double slit experiment.

In one of the experiments, which I find quite curious, photos are stopped when 2 consecutive polarization filters at 90 degrees are used; for example, if you put a polarized filter in the horizontal position, and then another in the vertical position, no photos will pass both filters. However, if between those 2 filters you add a third polarized filter at 45 degrees, or diagonal to the other 2, then most of the photon will pass (don't remember the exact percentage). Therefore, would it be reasonable to assume that polarization filters are interfering with the photons, or changing / modifying some of their properties; like polarization or spin?

 

[bhobba]

Therefore, would it be reasonable to assume that polarization filters are interfering with the photons, or changing / modifying some of their properties; like polarization or spin?

Sure.

Thanks
Bill

 

[adfreeman]

Sure.

You mean it like:

Sure... it's known already that the polarization filters are interfering / modifying properties on the photons?

or

Sure... it's possible, though we still don't know. In which case, would this be... kind of a big deal?

 

[bhobba]

Sure... it's known already that the polarization filters are interfering / modifying properties on the photons?

Of course:
http://alienryderflex.com/polarizer/

If you want to disuses these or similar experiments start a new thread.

Thanks
Bill

 

[adfreeman]

Thanks Bill,

I'll open a new thread. But can I ask a last question before I do?

Where does this formula comes from:

( cos(degrees of polarized filter difference) )²​

It's the one used in Bell's inequality to predict the results according to QM; for example:

( cos(120 deg) )² = 0.25 or 1/4​

I'm asking, who came up with it, and how?

 

[bhobba]

( cos(degrees of polarized filter difference) )²​

These things are easy to look up:
http://www.physicshandbook.com/laws/maluslaw.htm

Thanks
Bill

 

[Nugatory]

Therefore, would it be reasonable to assume that polarization filters are interfering with the photons, or changing / modifying some of their properties; like polarization or spin?

Yes, that is what is happening with the polarization (not spin here - that's a different property). The interaction with the first filter collapses the wave function of the surviving photons into the horizontally polarized state. This state is a superposition of 45-degree and 135-degree polarization (a calculation that we wouldn't bother with except that we know we're about to be asked about what happens when these photons reach the second filter). The collapse at the second filter leaves the surviving photons in the 45-degree polarized state; this state is a superposition of horizontal and vertical so some of them will pass the third filter and collapse to the vertical state. If we didn't have the 45-degree filter in the middle, we'd be passing the horizontally polarized photons from the first filter directly to the vertical filter, and nothing would pass.

(don't remember the exact percentage)

It's 50% of the photons that made it past the first filter, if the angle is exactly 45 degrees. This is intuitively reasonable from the symmetry of the situation (would you expect the result to change if we turned the experimental apparatus on its side?) or you can calculate it by writing $|H\rangle=\frac{\sqrt{2}}{2}(|45\rangle+|135\rangle)$ where H, 45, and 135 are the states that have 100% probability of passing through horizontal, 45-degree, and 135-degree filters respectively.

The connection with Bell's theorem and Aspect-type experiments is somewhat tenuous though (except that this is basic QM required as background before you dig into those topics). There are local hidden variable explanations for the behavior of single photons passing through polarizing filters.

 

[entropy1]

Therefore, would it be reasonable to assume that polarization filters are interfering with the photons, or changing / modifying some of their properties; like polarization or spin?

Of circular polarized photons, ½ gets trough. Of polarized photons, cos²(α) gets through. If you put circular polarized photons through a polarizer, they get polarized, and a following polarizer passes cos²(α).

 

[Nugatory]

These things are easy to look up:
http://www.physicshandbook.com/laws/maluslaw.htm

It is indeed Malus's law, but the history may be confusing. Early in the 19th century, Etienne Malus observed that if you passed light through two consecutive polarizing filters at an angle $\alpha$, the fraction of light that passed the second filter would be given by $\cos^2\alpha$ and this is Malus's law. He had no explanation for this phenomenon, it was just an observed fact (and given what was known about the nature of light at the time, this is all that could be expected).

In 1861 James Maxwell discovered the equations of classical electrodynamics and that light was electromagnetic radiation obeying those equations. Malus's law can be derived from these equations, so classical physics had an explanation for what had previously been an empirically observed but unexplained phenomenon.

Quantum electrodynamics, developed during the second quarter of the 20th century, introduced the notion of photons and showed that individual photons would display the same $\cos^2\alpha$ behavior. On the one hand, this result is completely unsurprising; the easiest way of explaining how a many-photon light beam would be attenuated in this way is to assume that the individual photons behave that way. On the other hand, the quantum calculations required to show that this is indeed the explanation are seriously hairy, so articles aimed at non-specialists generally just present it as a given that individual photons will display this $\cos^2\alpha$ behavior.

 

[DrChinese]

Where does this formula comes from:

( cos(degrees of polarized filter difference) )²​

...
I'm asking, who came up with it, and how?

Bill answered this. Sort of.

There is actually a bit more to this formula, and it is of course the same as Malus as Bill rightly says. Nugatory alluded to the "hairy" nature of the formula. The quantum mechanical "why" for entangled photons is actually a bit complicated. The first step is seen in equation (2) of this reference:

http://arxiv.org/abs/quant-ph/0205171

Matches are the sum of 2 cases (when you have PBSs rather than filters, and use detectors set at each of the PBS output ports - 4 total):

HH + VV

But you must substitute per the reference's formula to make it work for any H and V selections. You end up with something like:

(cos(A)+sin(B)) (cos(A)+sin(B)) + (-sin(A)+cos(B)) (-sin(A)+cos(B))

Which eventually comes back to the cos^2(A-B) formula when you work it through. I probably have something mislabeled because the derivation doesn't jump out at me right now. Else there are cobwebs in my brain.

At any rate, they work it through for polarizers and so will get half the matches, so they end up with 1/2 cos^2(A-B) at their formula (10). So you can how they arrive at that.

 

[adfreeman]

It is indeed Malus's law, but the history may be confusing. Early in the 19th century, Etienne Malus observed that if you passed light through two consecutive polarizing filters at an angle $\alpha$, the fraction of light that passed the second filter would be given by $\cos^2\alpha$ and this is Malus's law. He had no explanation for this phenomenon, it was just an observed fact (and given what was known about the nature of light at the time, this is all that could be expected).

In 1861 James Maxwell discovered the equations of classical electrodynamics and that light was electromagnetic radiation obeying those equations. Malus's law can be derived from these equations, so classical physics had an explanation for what had previously been an empirically observed but unexplained phenomenon.

Quantum electrodynamics, developed during the second quarter of the 20th century, introduced the notion of photons and showed that individual photons would display the same $\cos^2\alpha$ behavior. On the one hand, this result is completely unsurprising; the easiest way of explaining how a many-photon light beam would be attenuated in this way is to assume that the individual photons behave that way. On the other hand, the quantum calculations required to show that this is indeed the explanation are seriously hairy, so articles aimed at non-specialists generally just present it as a given that individual photons will display this $\cos^2\alpha$ behavior.

Thanks for clearing that. I really don't need to see the QM calculations behind that formula; it's enough to know that it's not only derived from observation.

 

[adfreeman]

The first step is seen in equation (2) of this reference:

http://arxiv.org/abs/quant-ph/0205171

Thanks...

That paper is exactly why I don't need to see the whole calculations.

My maths are a bit rusty after just using enough to program computers along all these years. But anyway, I don't think I would understand them even if I had them fresh. For example: I only know what this "| >" is by causality -as I just saw Leonard Susskind yesterday explaining the "ket" in a lecture... better tell you all now than after you waste your time on me with formulas... It's also the reason why I was about to ask for a good book that I could use to get up to date fast and easily in all these things; I mean, I'll probably needed it if I'm going to vindicate Einstein in the next thread I'm preparing about all this.

Matches are the sum of 2 cases (when you have PBSs rather than filters, and use detectors set at each of the PBS output ports - 4 total):

HH + VV

But you must substitute per the reference's formula to make it work for any H and V selections. You end up with something like:

(cos(A)+sin(B)) (cos(A)+sin(B)) + (-sin(A)+cos(B)) (-sin(A)+cos(B))

Which eventually comes back to the cos^2(A-B) formula when you work it through. I probably have something mislabeled because the derivation doesn't jump out at me right now. Else there are cobwebs in my brain.

At any rate, they work it through for polarizers and so will get half the matches, so they end up with 1/2 cos^2(A-B) at their formula (10). So you can how they arrive at that.

This part I get.

 

[Mark Harder]

And what makes human beings so special that their minds can collapse quantum systems, or bend spoons for that matter? I have a story that illustrates my point. Erwin Schroedinger sits in a room in house. Inside the room, there is a vial of hydrogen cyanide. There's also a weak radioactive source and a radiation detector to count the radioactive particles. A hammer is poised to smash the vial if the counter detects a nuclear decay. If the vial is smashed, Schroedinger is toast and never lives to write his ridiculous story. After a while, Erwin's cat, who he has kindly placed outside the room, gets hungry and comes looking for its master. So, the question is, is Erwin half dead and half alive until his cat peeks into the room and sees Erwin and collapses his wavefunction to either a dead physicist or a live one, no uncertainty about it?

 

[Nugatory]

And what makes human beings so special that their minds can collapse quantum systems

Nothing. This idea of consciousness causing collapse is a popular misconception about quantum mechanics, not something that you'll find when you study the real thing.

I have a story that illustrates my point...

You may be misunderstanding Schrodinger's thought experiment with the cat - easy enough to do, because this is another of those misconceptions widely repeated in the popular press. Neither Schrodinger nor anyone else at the time was actually suggesting that the cat might be in this superposition of half-dead/half-alive - everyone agrees that's not what happens. Instead Schrodinger was pointing out a problem in the then-current (1920s vintage) formulation of quantum mechanics, namely that the theory couldn't explain why it didn't happen.

It took another few decades to resolve this question. You can google for "Quantum Decoherence", although you may find the math to be somewhat heavy going. There's also Bruce Lindley's book "Where does the weirdness go?", which is a reasonably layman-friendly and math-free overview.

 

[Bruno81]

Ever since i was a young boy, i always had deep trouble understanding the nature of motion of macroscopic objects... It has always been the most incomprehensible fact of life - the simple fact that a 3d body stops existing at x,y,z at time T and reappears at x',y',z' at time T'. Quantum mechanics and its inherent measurements/decoherence of quantum systems provided by far the best insight into the workings of Nature as far as motion is concerned. But everything comes at a price - a non classical reality can be quite hard to grasp with respect to naive realism. The question about the Moon is more about existential(philosophical) problems and the nature of reality and much less, if any, about classical human beings bringing the Moon into existence.

 

[adfreeman]

Ever since i was a young boy, i always had deep trouble understanding the nature of motion of macroscopic objects... It has always been the most incomprehensible fact of life - the simple fact that a 3d body stops existing at x,y,z at time T and reappears at x',y',z' at time T'. Quantum mechanics and its inherent measurements/decoherence of quantum systems provided by far the best insight into the workings of Nature as far as motion is concerned. But everything comes at a price - a non classical reality can be quite hard to grasp with respect to naive realism. The question about the Moon is more about existential(philosophical) problems and the nature of reality and much less, if any, about classical human beings bringing the Moon into existence.

I kind of agree with you when you say that the question looks more philosophical than related to physics -though I always took it as a metaphor in this context-. What I find even more interesting is the possibility of our combined consciousness creating all this as we go. I would dare to go even further, as sometimes I have the hunch that when I die the whole universe will simply cease to exist. Sorry guys, that means that you are also a product of my imagination.

And it's funny that you referred to the movement of 3D bodies through space and time in that way. Just this morning I was considering: is it possible that space and time could also be quantized; therefore jumping through space-time in the fashion you described?

 

[Nugatory]

it possible that space and time could also be quantized; therefore jumping through space-time in the fashion you described?

It is possible, but there is no particularly convincing theory or experimental evidence to lead us to believe that it is.

(There are popular misunderstandings about the significance of the Planck length and Planck time - we even have an Insights article on this: https://www.physicsforums.com/insights/hand-wavy-discussion-planck-length/)