How does QE explain more mismatches in Bell's test at wider angles?

In summary: QM) is in accordance with the probability laws. This "decision" is not available to the local hidden variable theories. Thus the result is not random but also not determined by "local hidden variables".In summary, Quantum Entanglement can lead to mismatches in Bell's tests at wider angles due to the correlations between particles that cannot be explained by local hidden variable theories. This can be interpreted as breaking either realism or locality, and QM is the only theory that can explain this phenomenon.
  • #1
San K
911
1
While I think that the phenomena of Quantum Entanglement exists, it's real; it's interesting to understand more about it.

How does QE/QM explain more mismatches (relatively to simple probability calculations) in Bell's test at wider angles?

Or alternatively: Why does/would QE result in lower matches (rather than higher matches) at wider angles?

QE = quantum entanglement

In Bell's Tests, we get the following results: ----------------Per QM/Actual Experiment
----------------Mismatches (out of 100)at (0,30) --------------- 25
at (-30,0) -------------- 25
At (-30,30) ------------- 75Per LHV the result at (-30, 30) should have been 50.

Thus we are getting 25 more mismatches. No LHV theory can explain this, however QM can explain this mathematically and conceptually.What is the conceptual explanation per QM?

Is it something like below?:

Since the two entangled photons are somehow "connected/entangled" the chances/probability of a match will decrease because both the photons have to satisfied "in a connected manner" (i.e. both have to encounter "good" angles in a "connected/entangled manner").

or to take another example:

Rating a movie as Liked or Disliked

Case A - Two friends watch a movie and communicate with each other prior to rating the movie. And the friends have the ability to influence each other's rating.

Case B - Two individuals watch a movie and never communicate with each other and rate a movie.
wiki said:
The Bell test experiments have been interpreted as showing that the Bell inequalities are violated in favour of QM. That interpretation follows not from any clear demonstration of super-luminal communication in the tests themselves, but solely from Bell's theory that the correctness of the quantum predictions necessarily precludes any local hidden-variable theory.

There are two parts here:

Part 1 -- no theory (other than QM) can explain this
Part 2 -- QM can explain this
 
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  • #2
I think the point is, the entanglement allows for correlations that cannot be mediated strictly with information that is "carried with" each particle. This gives us two choices of interpretation: either information about the system retains a holistic or global character (also called "contextuality"), or else information can be exchanged superluminally. The first case is interpreted as breaking "realism", and the second is interpreted as breaking "locality". Choose your poison.
 
  • #3
Ken G said:
I think the point is, the entanglement allows for correlations that cannot be mediated strictly with information that is "carried with" each particle. This gives us two choices of interpretation: either information about the system retains a holistic or global character (also called "contextuality"), or else information can be exchanged superluminally. The first case is interpreted as breaking "realism", and the second is interpreted as breaking "locality". Choose your poison.

Thanks Ken G. Agree with the part you wrote above.

To understand this further -

Let's say the real test (i.e. the Bell's experiment) gave the result P(-30, 30) = 35 ...(instead of 75)

(we are assuming reality/universe is such way)

i.e. mismatches are lesser (at wider angles) than that predicted by probablity laws

Could we, even in such a case (universe), apply the same logic and, say that -- ...we are either breaking "realism" or "locality"?
 
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  • #4
I think I got the answer. The mismatches are not always more.

After the 90 degree difference the trend reverses in the graph.

Mismatches are actually lesser (between 90-180 degrees) than that predicted by linear/probability curve as can be seen in the graph below.

0-90 = mismatches more than that predicted by probability/linear
90-180 = mismatches less than that predicted by probability/linear
180-270 = mismatches less than that predicted by probability/linear
270-360 = mismatches more than that predicted by probability/linearhttp://upload.wikimedia.org/wikipedia/commons/7/77/StraightLines.svg

http://upload.wikimedia.org/wikipedia/commons/7/77/StraightLines.svg
 
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  • #5
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  • #6
DrChinese said:
San,

Good stuff!

-DrC

thanks DrChinese. So, is the logic in post #4 above (by and large) correct then?...

DrChinese said:
A minor note: the zero crossings on your graph should be every 45 degrees rather than 90. See the link, this is on a scale of 0 to 1:
http://drchinese.com/images/Bell.UnfairSamplingAssumption1.jpg

-DrC

well said DrChinese, you mean the zero "difference" between QM and Linear (and not the zero correlation) crossings? good catch, thanks for pointing that out.

so in the diagram (in post 4) should there be 8 "flaps/convex/Ds" instead of 4?
 
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  • #7
DrChinese said:
-DrC

EDIT: Oops I mean every 90 degrees rather than 180.

The graph (in post 4) is showing at 90 degrees only. I think your earlier, prior to the edit, was correct...
 
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  • #8
San K said:
Since the two entangled photons are somehow "connected/entangled" the chances/probability of a match will decrease because both the photons have to satisfied "in a connected manner" (i.e. both have to encounter "good" angles in a "connected/entangled manner").


From that I get the impression the case is saying that entangled particles only exist if they encounter the appropriate angles to show the QM mis-match rate. This doesn't seem correct.


There are two parts here:

Part 1 -- no theory (other than QM) can explain this
Part 2 -- QM can explain this
QM can PREDICT the right outcomes. Any future theory that supercedes QM will need to include these predictions.
 
  • #9
StevieTNZ said:
From that I get the impression the case is saying that entangled particles only exist if they encounter the appropriate angles to show the QM mis-match rate. This doesn't seem correct.

No I did not mean that. Sorry if I did not put this better.

What I mean is - (and maybe there is a better way to put this) -

Entangled particles as a single unit "decide" (by looking at both the angles) whether to go or no-go.

in contrast to -

Two un-entangled particles (with the supposed local hidden variables) that "decide" separately without having to "communicate" with each other.

StevieTNZ said:
QM can PREDICT the right outcomes. Any future theory that supercedes QM will need to include these predictions.

agreed, not disputing that.
 
  • #10
San K said:
While I think that the phenomena of Quantum Entanglement exists, it's real; it's interesting to understand more about it.

How does QE/QM explain more mismatches (relatively to simple probability calculations) in Bell's test at wider angles?

Or alternatively: Why does/would QE result in lower matches (rather than higher matches) at wider angles?

QE = quantum entanglement
[..]
There are two parts here:

Part 1 -- no theory (other than QM) can explain this
Part 2 -- QM can explain this
Good points - and I start to think that such summaries are misleading (wrong).
More precise would be, I think (but if I'm wrong then I would like be corrected!):

Part 1 -- this is incompatible with any reasonable "local" theory (=without magic or "spooky" effects at a distance)
Part 2 -- QM predicts this, but does not (and perhaps cannot) explain it.

As a matter of fact, it all started out with attempts to explain the predicted QM effects with "local realism".
 
  • #11
harrylin said:
Good points - and I start to think that such summaries are misleading (wrong).
More precise would be, I think (but if I'm wrong then I would like be corrected!):

Part 1 -- this is incompatible with any reasonable "local" theory (=without magic or "spooky" effects at a distance)
Part 2 -- QM predicts this, but does not (and perhaps cannot) explain it.

As a matter of fact, it all started out with attempts to explain the predicted QM effects with "local realism".

Agreed, your edits are valid, Harrylin. Well corrected.

there is a Minor addition - QM can predict somethings but not others.

For example:
Can predict

if a (bunch) of photon will form an interference pattern or not

Cannot predict
where the photon will land on the screen

Thus if we do no-which-way, QM can predict that the photon will land one of the fringes but it cannot predict which fringe and its position on the screen/fringe. As per QM the position, on the screen, can never be predict (with100% accuracy) you can only assign probabilities to it.
 
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Related to How does QE explain more mismatches in Bell's test at wider angles?

1. How does quantum entanglement (QE) explain mismatches in Bell's test?

Quantum entanglement is a phenomenon in which two or more particles become connected in such a way that the state of one particle affects the state of the other, regardless of the distance between them. This means that two particles can have correlated properties even if they are physically separated. In Bell's test, this explains how measurements on one particle can seemingly instantaneously affect the state of the other, leading to mismatches between the predictions of quantum mechanics and classical physics.

2. What are the wider angles in Bell's test and how do they contribute to mismatches?

The wider angles in Bell's test refer to the orientation of the measuring devices used to observe the entangled particles. These angles can be manipulated to measure different properties of the particles. When the angles are wider, the particles are more likely to have mismatched measurements, as the correlations between their states are more apparent.

3. Why do mismatches occur more frequently at wider angles in Bell's test?

In Bell's test, measurements at wider angles reveal more about the properties of the entangled particles. This means that the effects of quantum entanglement are more pronounced, leading to a higher frequency of mismatches between the predictions of quantum mechanics and classical physics. Essentially, wider angles provide a more sensitive test for the presence of quantum entanglement.

4. How does quantum mechanics explain mismatches in Bell's test at wider angles?

In quantum mechanics, the state of a particle is described by a wave function, which can be thought of as a set of probabilities for different measured outcomes. When two particles are entangled, their wave functions are correlated, and measurement on one particle affects the wave function of the other. At wider angles in Bell's test, the effects of this entanglement become more apparent, leading to mismatches between the predicted probabilities and the actual measurements.

5. Can quantum entanglement be used to send information faster than the speed of light?

No, quantum entanglement cannot be used to send information faster than the speed of light. While entangled particles may seem to communicate instantaneously, this does not violate the principle of causality or allow for faster-than-light communication. This is because the measurement outcomes of entangled particles are still random and cannot be controlled or predicted, meaning no information can be transmitted between them.

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