Wheeler's Delayed Choice Experiment

  • Thread starter byron178
  • Start date
  • #26
xts
881
0
ok, to me a violation of causality is an influence that can affect the past in reality,i hope you see the confussion here.
I see, and I am happy you've finally accepted common-sense defnition of reality as something detectable.
I also hope you see that Wheeler experiment does not influence past physical reality (in a meaning you've just accepted) and thus doesn't violate causality.

also is there a view in which the present does not affect the past?
Oooch? Are there people who do not believe in ghosts, invisible dragons and photon paths? Yes. They are. Not many, but there are some.
 
  • #27
157
0
I see, and I am happy you've finally accepted common-sense defnition of reality as something detectable.
I also hope you see that Wheeler experiment does not influence past physical reality (in a meaning you've just accepted) and thus doesn't violate causality.


Oooch? Are there people who do not believe in ghosts, invisible dragons and photon paths? Yes. They are. Not many, but there are some.
im confused because in post #16 you said that the present can influence the past.
 
  • #28
xts
881
0
im confused because in post #16 you said that the present can influence the past.
#16???? I said so?
I was sure it is me who need some sleep (2AM) to think clearly.... Goodnight then!
 
  • #29
157
0
#16???? I said so?
I was sure it is me who need some sleep (2AM) to think clearly.... Goodnight then!
im sorry i was wrong,i meant that you agreed with cramer that the present can influnce the past.
 
  • #30
71
0
so its safe to say they wheelers delayed choice allows influence to the past? i ask this because you said that he was right in saying that the present can influence the past.
Wheeler proposed delayed time experiments to demonstrate that actions in a 'present' could alter the outcome of an experiment where photons (or any other quantum object) began their path before the alteration occured. Experiments have demonstrated over and over again that he was correct.
To make this clear.
0.Wheeler did accept that actions in the present can alter the past. He went to the extreme of refering to measurements in the present altering a photons history to the 'present' from it's inception billions of years ago, to make that point.
the experiments - precis
1. a photon begins it's path.
2. the path of one of the possibilities of the photon is altered.
3. a measurement of each photon's path is noted.

The statistical results of such experiments (and that is necessarily all you'll ever get-statistical non specific data) is in agreement with the conditions if the experiment had been set up ahead of time ,as if the entire experiment was like when the photon's path was altered.

There is only one model, the De Broglie-Bohm theory, that can offer an explanation that is not either acausal or time-reversed.

perhaps there is another model? (i.e.do you know of one or is De Broglie-Bohm what you aver to?)

Personally I prefer a block universe acausal model.

mathal
 
  • #31
157
0
Wheeler proposed delayed time experiments to demonstrate that actions in a 'present' could alter the outcome of an experiment where photons (or any other quantum object) began their path before the alteration occured. Experiments have demonstrated over and over again that he was correct.
To make this clear.
0.Wheeler did accept that actions in the present can alter the past. He went to the extreme of refering to measurements in the present altering a photons history to the 'present' from it's inception billions of years ago, to make that point.
the experiments - precis
1. a photon begins it's path.
2. the path of one of the possibilities of the photon is altered.
3. a measurement of each photon's path is noted.

The statistical results of such experiments (and that is necessarily all you'll ever get-statistical non specific data) is in agreement with the conditions if the experiment had been set up ahead of time ,as if the entire experiment was like when the photon's path was altered.

There is only one model, the De Broglie-Bohm theory, that can offer an explanation that is not either acausal or time-reversed.

perhaps there is another model? (i.e.do you know of one or is De Broglie-Bohm what you aver to?)

Personally I prefer a block universe acausal model.

mathal
So it does allow us to interact with the past? does it happen in reality? so that would mean it violates a type of causality?
 
  • #32
xts
881
0
There is only one model, the De Broglie-Bohm theory, that can offer an explanation that is not either acausal or time-reversed.
You missed one word. You should say There is only one realistic model...
'Realistic' :== 'assuming objective existence of intuitive, but nondetectable entities like "photon paths" '
Or maybe you meant that using the word 'acausal'...?

Anyway - since EPR/Bell I definitely prefer and advocate non-realistic models than shy time-reversed causalities , Bohmian pilots, and similar constructs.
 
  • #33
157
0
You missed one word. You should say There is only one realistic model...
'Realistic' :== 'assuming objective existence of intuitive, but nondetectable entities like "photon paths" '
Or maybe you meant that using the word 'acausal'...?

Anyway - since EPR/Bell I definitely prefer and advocate non-realistic models than shy time-reversed causalities , Bohmian pilots, and similar constructs.
has it been verified that wheelers expierament allows it to influence the past?
 
  • #34
xts
881
0
Come on!

It is fully verified and non-controversial what is the outcome of the Wheeler's experiment.

The answer to your question depends only on definition you put under the word: 'influence', which depends in turn on your ontological and lexical taste.

The dispute is not about anything related to the world. It is related to the word. And, unfortunately, this word has no precisely defined and commonly accepted meaning - different people (philosophers) use it differnetly.
 
Last edited:
  • #35
Chronos
Science Advisor
Gold Member
11,408
738
Simultaneity is the issue here. In GR, there is no absolute simultaneity. Extending quantum theory to macroscopic reality is as difficut as extending GR to the quantum realm.
 
  • #36
60
0
has it been verified that wheelers expierament allows it to influence the past?
The problem with Wheelers experiment and the like is that the explanations either be very mysterious - or stick to QM theory and do not think!

The latter is the safest because almost all models of understanding have errors compared to the theory - for example by being (gross) simplifications - or by introducing unneccessary ideas that are not part of the theory.

A guaranteed wrong model - which often is easy for analysis - is to imagine that the photons forming waves in space like a boat on the lake (With dark energy - space is hardly empty). When photons meetings a double split or a half-silvered mirror or a PBS then waves go both ways - but the ship = the particle follows only one of them. Interference takes place between the waves and then they control the ship = particle.

Following this model, there is no time problem - since Wheeler just stop one wave (with or without particles) - and thereby stop the interference.

Remember it is not a theory - stick to that - only a crutch.


(PS Many (all?) of this type of experiments use coincidence counters - ie that it is hard to talk about a real disturbed time sequence.)
 

Related Threads on Wheeler's Delayed Choice Experiment

  • Last Post
Replies
3
Views
3K
  • Last Post
Replies
7
Views
2K
Replies
6
Views
2K
Replies
6
Views
4K
Replies
0
Views
936
  • Last Post
Replies
2
Views
2K
Replies
157
Views
8K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
6
Views
3K
  • Last Post
Replies
2
Views
1K
Top