Explanation needed on QM double slit experiment

[Time Traveler]

As I understand, in double slit experiment:

a) if particles are observed then they form two spots on screen 

b) if not - they create interference pattern.

Then, it is said that this interference pattern is graphical illustration of probability function, called wave function. Wave function shows us the probability with which particle would hit the screen if observed.

But that is not the case ! When observed, particles hit the screen only in two places. In fact, if this would be true then observed particles would create exactly same interference pattern.

 

Can someone clarify this ?

[SoonHei]

9 minutes ago, Time Traveler said:

As I understand, in double slit experiment:

a) if particles are observed then they form two spots on screen 

b) if not - they create interference pattern.

Then, it is said that this interference pattern is graphical illustration of probability function, called wave function. Wave function shows us the probability with which particle would hit the screen if observed.

But that is not the case ! When observed, particles hit the screen only in two places. In fact, if this would be true then observed particles would create exactly same interference pattern.

 

Can someone clarify this ?

consiouness creates reality... when you observe it, you collapse the wave function down to the the 1 of the two slits it will go thru without any interference pattern.

the act of observing collapses it.

 

and when we are not observing which slit it goes in from, it acts as a wave creating the interference pattern - showing all probabilities that could exist... 

 

also. our expectation about how objects/particles should behave is also part of it. when viewing the single particle, we expect it to act like a solid ball and that's what it does. 

[lmfao]

@Time Traveler you'd be better of reading about the experiment on other websites. 

[Mafortu]

A common misconception and misunderstanding for those that love to copy- paste this study.

Its not that observing it causes a reaction, but shooting a LASER a it in order to be able to observe it changes the behavior

Its just science and mathematics, not hocus pocus stuff.

[Time Traveler]

Leo, you said you've studied QM.

Can you show me where I'm making mistake ?

Why of all the probabilities showed by interference pattern only 2 realize itself ?

[tsuki]

@Time Traveler Your misconceptions arise from the ambiguity of the word 'observe'.
We do observe the result of the experiment by noticing the interference pattern on the screen.
Then, we try to actually observe the motion of particles, as in: which particle went through which slit.
If we can tell which particle went through which slit, then the interference pattern on the screen disappears.
There simply are two dots, instead of many slits.

We can either observe which paths the particles took, or the interference pattern.
Not both at the same time.

Edited August 2, 2018 by tsuki

[Dogsbestfriend]

@Mikael89  Depends what you mean by detector, if they place screens right after the slits through which the photons pass through to try and capture that info - it will collapse the wave function. 

@Mafortu What? where are you getting that a laser is shot to observe the result?  

[Elisabeth]

@Time Traveler  As already indicated, you are missing the fact that quantum MEASUREMENT actually changes the wave function. (As a physicist, I'll deliberately use measurement on this forum, not observation, to leave consciousness out of the debate in the first run.) So if we, by any physical means (like the aforementioned laser) determine the path the electron goes through, the interaction of the measured object (electron) and the measuring device (laser) has an impact on the measured system. The electron's wave-function "collapses" into one of the two classical states: going through left or right slit, and this is reflected on the screen. ( Also note that what's measured on the screen is not actually the wave function but (wave function squared), i.e. probability. )

If the above explanation seems a little weird, that's because it is. Quantum mechanics is inherently weird, and even the most standard interpretation has some flaws. That's why you can also have other, even more weird interpretations.

One thing that is debatable, and most discussions on consciousness and QM will explicitly or implicitly use this issue, is "what the heck consists a measurement", as well as "so you divide your system into something 'quantum' and some 'classical' measuring apparatus, why would you do the division exactly this way?" Same issue in two different wordings. Physicists know it's a bit of an arbitrary distinction and how to include your measuring device into the math if needed (and move the arbitrary distinction one level up). Leo has debated at length in his series how the arbitrariness of this distinction, if we try to include the whole universe into the quantum system, in his opinion points to non-duality. But for your question, we don't need that.

[Dogsbestfriend]

@Elisabeth Hey Elisabeth, regarding effects of consciousness specifically on the double slit experiment gonna share this interesting vid about a slightly different version of the experiment:

 

[Elisabeth]

3 minutes ago, Dogsbestfriend said:

@Elisabeth Hey Elisabeth, regarding effects of consciousness specifically on the double slit experiment gonna share this interesting vid about a slightly different version of the experiment:

Is that the Dean Radin guy? I've heard about him. I don't have an opinion yet. I don't know if he's right. There are some critiques regarding his scientific practices, which is to be expected either way. I read in detail the 'independent replication' of his experiment, but there are issues with the statistics. They first found nothing, then changed the procedure of data processing. So not impressed, you can always get an effect out of the fluctuations if you try hard enough. But thanks, I may watch it later, perhaps.

[Time Traveler]

Thanks all !

I realized where my mistake was. Happens when you are not listening carefully

[Nahm]

“Wave function” points at reality (You) from within a scientific vernacular and paradigm , particles are dream stuff (you). The only way ‘around’ nonduality is self deception (pretending there is something other than You). Doesn’t matter if it’s a “lofty” topic like QM, or something as simple as a drop of rain. The observer, the observed, measurement, ‘collapse’, etc, all dream stuff. When seen in it’s entirety, the illusion is just light.

The benefit of seeing you exist as pure potentiality........whatever you want to be. 

Freedom from the conditioning of believing in the appearance of consistent “reality”. Shocking freedom. 

The brain doesn’t like this because it’s purpose is to hide this very fact by assigning meaning. Put another way, the role of the brain is not to solve the observer “problem”, but to hide the Truth, that there is no problem. If there’s no meaning, there’s no problem, if there’s no problem there’s no story. 

No meaning assigned = total freedom. Everything you could want to do is the same when you let all meaning go. Because in truth it doesn’t matter in the most literal sense what you are doing right now. 

It traces back to the concept of identity, which is all falsity. If I want to be nice, there’s meaning. If I want to be smart, there’s meaning. But there is no such thing as identity, because there is no such thing as something else to identify you. 

You can think you know more about what you are, and you’ll know less about what you’re doing in this life. 

You can focus more on what you want to be doing with this life, but because in that you’ll be changing (in a mental appearance / idea of self sense), you’ll paradoxically know less about yourself while discovering more about yourself. Until there is only self. The pure potentiality of you. 

The wisest person I’ve met once said, “It’s nonsense”. 

[Dogsbestfriend]

@Elisabeth The number of subjects in the replication are much much smaller. But yea I thought it was interesting and he seemed quite coherent. Not that it means I believe it but he made a strong case for it and came across as a sensible person. The interesting thing is the did the experiment across the internet as well, let any participate that wanted to etc. 

[Mafortu]

18 hours ago, Mikael89 said:

No, you are wrong, they have ruled out that. The detector itself doesn't affect it.

Elisabeth already explained it better than I ever could, but do you have a source on that?

[Hamilcar]