Wave function won't collapse under a microscope?

[ThiagoMNobrega]

TL;DR Summary

I made experiments in my room and I think I am able to observe the wave function without its collapse, can anyone assist me?

So what am I doing wrong here? I can clearly observe it, I'm nearly sure I can tell which particles are going throw each slit if I used another laser too. My suspicion is that the electrical current of the photon detector that uses germanium or silicon to detect the particles are influencing the outcome, as with a microscope, some lasers and two slits are able to produce consistent results. I filmed these and showed to a buddy of mine (that works at a particle accelerator) that told me his head "bugged" once he saw the video.

Am I doing something wrong here or can someone help me out with a scientific research article in case it is something relevant to the quantum mechanics world? (I have a background in economics and computer science)

- Thiago M Nóbrega

 

[PeterDonis]

I made experiments in my room

You will need to provide much more detail than this if you expect anyone to be able to make any useful comments...

I think I am able to observe the wave function without its collapse

...particularly if you are claiming this.

I can clearly observe it

Clearly observe what? All I see is a blurry image of...something.

If what you have here is a detector screen that is showing some kind of image of light after it has gone through a double slit apparatus, I have no idea why you think you are "observing the wave function without its collapse". You are just seeing a blurry version of an interference pattern, which is exactly what you should expect to see, and what everyone who has run this experiment since Thomas Young first did it in the early 1800s has seen. (I assume it's blurry because whatever home-built apparatus you have is not very accurate.)

 

[PeterDonis]

in case it is something relevant to the quantum mechanics world?

If what you are showing is an image of a detector screen with an interference pattern, no, you don't need quantum mechanics to explain that. The classical wave model of light explains it just fine. In fact, the Thomas Young double slit experiment I referred to in my last post was one of the key experiments that established the classical wave model of light.

 

[ThiagoMNobrega]

You will need to provide much more detail than this if you expect anyone to be able to make any useful comments...


...particularly if you are claiming this.


Clearly observe what? All I see is a blurry image of...something.

If what you have here is a detector screen that is showing some kind of image of light after it has gone through a double slit apparatus, I have no idea why you think you are "observing the wave function without its collapse". You are just seeing a blurry version of an interference pattern, which is exactly what you should expect to see, and what everyone who has run this experiment since Thomas Young first did it in the early 1800s has seen. (I assume it's blurry because whatever home-built apparatus you have is not very accurate.)

I think I clearly observe the interference pattern with a laser, two slits and a microscope recording acting as the detector. Yes, I am aware that light travels in a wave format. But, the double slit experiment with photon detectors seem to "collapse once observed".

Me and my friend seem to agree it shows the interference pattern, but I got that while filming and watching it. At which point should the wave function collapse? shouldn't it collapse once it is observed? How come the output doesn't collapse like they do with photon detectors?

 

[ThiagoMNobrega]

If what you are showing is an image of a detector screen with an interference pattern, no, you don't need quantum mechanics to explain that. The classical wave model of light explains it just fine. In fact, the Thomas Young double slit experiment I referred to in my last post was one of the key experiments that established the classical wave model of light.

Also, thank you so much for taking your time to look into this, we are really confused about my results as it did not get the "collapse" expected. the results is a video that seems to be showing the wave function and at no point it collapses. Yes it is blurly as the equipament I have at home isn't the best. I do live 5 minutes away from my countries' equivalent of harvard, so I guess I could go there and ask professors for better equipament to reproduce my experiment more professionally. I just really don't want to waste anyone time and understand better what's going on.

 

[PeroK]

Me and my friend seem to agree it shows the interference pattern, but I got that while filming and watching it. At which point should the wave function collapse? shouldn't it collapse once it is observed? How come the output doesn't collapse like they do with photon detectors?

The wavefunction is not a "thing" that you can see. It's an abstract mathematical construction that underpins the theory of QM.

 

[ThiagoMNobrega]

The wavefunction is not a "thing" that you can see. It's an abstract mathematical construction that underpins the theory of QM.

Oh, so isn't the whole thing about the double slit experiment that the wavefunction collapses and the output is changed with observation? Maybe that's the part I'm getting wrong...

this is what I understand of the wave function: "In quantum mechanics, wave function collapse occurs when a wave function—initially in a superposition of several eigenstates—reduces to a single eigenstate due to interaction with the external world. This interaction is called an "observation""

 

[PeroK]

Oh, so isn't the whole thing about the double slit experiment that the wavefunction collapses and the output is changed with observation?

It depends what you mean by "observation". With light there is essentially no way to observe the light at the slits and have the light reach the detector screen. This is because to observe a photon you must absorb it.

The only options you have with light are the double-slit or the single-slit (by closing one of the slits).

Maybe that's the part I'm getting wrong...

this is what I understand of the wave function: "In quantum mechanics, wave function collapse occurs when a wave function—initially in a superposition of several eigenstates—reduces to a single eigenstate due to interaction with the external world. This interaction is called an "observation""

That's true but irrelevant here.

 

[ThiagoMNobrega]

It depends what you mean by "observation". With light there is essentially no way to observe the light at the slits and have the light reach the detector screen. This is because to observe a photon you must absorb it.

The only options you have with light are the double-slit or the single-slit (by closing one of the slits).

That's true but irrelevant here.

So I'm using lasers that continuously shoot out photons. The microscope seems to pick up wavy patterns once the laser goes through both of the slits. Since the microscope is recording (I'm also straight up looking at the experiment going on) doesn't that count as an observation?

As to which photons pass through which slit, I'd imagine I can use two laser pointers with different colors and than check out the recording to see which colored photons are at which side..

I'm a bit lost on the there is no way to observe a photon, lasers shoot out many photons and I'm able to observe it. Individually I'd need a super microscope I guess, but I don't really see how that would influence things if I seem to be able to record and observe the pattern...

(Also, sorry for the many questions! I'm very thankful for every reply!)

 

[ThiagoMNobrega]

Also, I'm very curious about some of the results of my experiments, like this frame shot from one of the videos I made... if you zoom out it looks even more like a wave...

 

[PeterDonis]

the double slit experiment with photon detectors

Is not the experiment you are running. With a light source that has low enough intensity that individual "photon" impacts can be seen at the detector (i.e. individual dots of light that, over time, build up an interference pattern), then you do need to bring in quantum mechanics to explain what is going on. But you're not doing that.

seem to "collapse once observed".

Each individual photon impact on the detector in the low intensity version of the experiment I described above corresponds to a "collapse" in QM, yes. (But what exactly "collapse" means depends on which interpretation of QM you adopt. Discussion of QM interpretations belongs in the interpretations subforum, not here.)

At which point should the wave function collapse?

With the version of the experiment you are running, the "wave function" viewpoint isn't even necessary. Basically you are looking at an interference pattern formed by classical light. Such light can, for all practical purposes, be viewed as "always collapsed". There is no need for QM or "collapse" at all in analyzing the experiment you are running. If you want to test anything about QM, you need to have a different apparatus that can run the low intensity version of the experiment I described above.

How come the output doesn't collapse like they do with photon detectors?

Your belief that "the output doesn't collapse" is incorrect. See above.

the results is a video that seems to be showing the wave function

No, it doesn't, it shows a classical interference pattern.

I'm using lasers that continuously shoot out photons.

No, you are using lasers that continuously shoot out light. Viewing this light as "photons" is pointless for your experiment because the light intensity is too high for that.

Since the microscope is recording (I'm also straight up looking at the experiment going on) doesn't that count as an observation?

An "observation", as far as QM is concerned, happens as soon as the light hits your detector.

As to which photons pass through which slit, I'd imagine I can use two laser pointers with different colors and than check out the recording to see which colored photons are at which side..

If you have two lasers instead of one, you don't have a single light source, you have two light sources, and with laser pointers, it will be impossible for the two light sources to be coherent enough to tell you anything useful. You'll just see a blob of the two different colors mixed.

"Which-way" experiments of this sort with light are best done with polarizers behind each slit. That would indeed be testing aspects of QM, if your light source is good enough. (I'm not sure if "laser pointers" would qualify.) With a good enough light source, you should be able to "tune" the degree to which you see interference at the detector by adjusting the relative orientations of the polarizers at the two slits.

I'm a bit lost on the there is no way to observe a photon

Not with light of the intensity you're using. There is no way to resolve such light into individual photons.

With light of low enough intensity, as I said above, you can see individual "photon" impacts on a suitable detector as dots. There are also photodetectors that emit clicks (by amplifying single photons into an electric current that can drive a speaker). But an ordinary microscope is not the right tool for these kinds of things.

 

[PeroK]

So I'm using lasers that continuously shoot out photons.

You need to be careful with this model of photons, as we are really talking about the quantised EM field, which is more complicated than bullet-like particles of light.

The microscope seems to pick up wavy patterns once the laser goes through both of the slits. Since the microscope is recording (I'm also straight up looking at the experiment going on) doesn't that count as an observation?

Yes, and you observe a double-slit interference pattern built up from many photons interacting with the screen. There is no observation at the slits is the point.

As to which photons pass through which slit, I'd imagine I can use two laser pointers with different colors and than check out the recording to see which colored photons are at which side..

You could put different polarisers on each slit and then ... the double-slit interference pattern would be replaced by two single-slit patterns. This is the heart of QM. This is what is heuristically called "wave-function collapse". The coherent wave-function before the slits collapses into a superposition of different polarised states after the slits.

I'm a bit lost on the there is no way to observe a photon

Not without absorbing it. A car, for example, can be observed without destroying it. If you observe a photon, then it's gone.

 

[ThiagoMNobrega]

Is not the experiment you are running. With a light source that has low enough intensity that individual "photon" impacts can be seen at the detector (i.e. individual dots of light that, over time, build up an interference pattern), then you do need to bring in quantum mechanics to explain what is going on. But you're not doing that.


Each individual photon impact on the detector in the low intensity version of the experiment I described above corresponds to a "collapse" in QM, yes. (But what exactly "collapse" means depends on which interpretation of QM you adopt. Discussion of QM interpretations belongs in the interpretations subforum, not here.)


With the version of the experiment you are running, the "wave function" viewpoint isn't even necessary. Basically you are looking at an interference pattern formed by classical light. Such light can, for all practical purposes, be viewed as "always collapsed". There is no need for QM or "collapse" at all in analyzing the experiment you are running. If you want to test anything about QM, you need to have a different apparatus that can run the low intensity version of the experiment I described above.


Your belief that "the output doesn't collapse" is incorrect. See above.


No, it doesn't, it shows a classical interference pattern.


No, you are using lasers that continuously shoot out light. Viewing this light as "photons" is pointless for your experiment because the light intensity is too high for that.


An "observation", as far as QM is concerned, happens as soon as the light hits your detector.


If you have two lasers instead of one, you don't have a single light source, you have two light sources, and with laser pointers, it will be impossible for the two light sources to be coherent enough to tell you anything useful. You'll just see a blob of the two different colors mixed.

"Which-way" experiments of this sort with light are best done with polarizers behind each slit. That would indeed be testing aspects of QM, if your light source is good enough. (I'm not sure if "laser pointers" would qualify.) With a good enough light source, you should be able to "tune" the degree to which you see interference at the detector by adjusting the relative orientations of the polarizers at the two slits.


Not with light of the intensity you're using. There is no way to resolve such light into individual photons.

With light of low enough intensity, as I said above, you can see individual "photon" impacts on a suitable detector as dots. There are also photodetectors that emit clicks (by amplifying single photons into an electric current that can drive a speaker). But an ordinary microscope is not the right tool for these kinds of things.

Thank you so much! I'll

Is not the experiment you are running. With a light source that has low enough intensity that individual "photon" impacts can be seen at the detector (i.e. individual dots of light that, over time, build up an interference pattern), then you do need to bring in quantum mechanics to explain what is going on. But you're not doing that.


Each individual photon impact on the detector in the low intensity version of the experiment I described above corresponds to a "collapse" in QM, yes. (But what exactly "collapse" means depends on which interpretation of QM you adopt. Discussion of QM interpretations belongs in the interpretations subforum, not here.)


With the version of the experiment you are running, the "wave function" viewpoint isn't even necessary. Basically you are looking at an interference pattern formed by classical light. Such light can, for all practical purposes, be viewed as "always collapsed". There is no need for QM or "collapse" at all in analyzing the experiment you are running. If you want to test anything about QM, you need to have a different apparatus that can run the low intensity version of the experiment I described above.


Your belief that "the output doesn't collapse" is incorrect. See above.


No, it doesn't, it shows a classical interference pattern.


No, you are using lasers that continuously shoot out light. Viewing this light as "photons" is pointless for your experiment because the light intensity is too high for that.


An "observation", as far as QM is concerned, happens as soon as the light hits your detector.


If you have two lasers instead of one, you don't have a single light source, you have two light sources, and with laser pointers, it will be impossible for the two light sources to be coherent enough to tell you anything useful. You'll just see a blob of the two different colors mixed.

"Which-way" experiments of this sort with light are best done with polarizers behind each slit. That would indeed be testing aspects of QM, if your light source is good enough. (I'm not sure if "laser pointers" would qualify.) With a good enough light source, you should be able to "tune" the degree to which you see interference at the detector by adjusting the relative orientations of the polarizers at the two slits.


Not with light of the intensity you're using. There is no way to resolve such light into individual photons.

With light of low enough intensity, as I said above, you can see individual "photon" impacts on a suitable detector as dots. There are also photodetectors that emit clicks (by amplifying single photons into an electric current that can drive a speaker). But an ordinary microscope is not the right tool for these kinds of things.

Oh, thank you so much! This clears a lot of stuff up and sets a clear path to improve my Sunday experiments!

 

[ThiagoMNobrega]

You need to be careful with this model of photons, as we are really talking about the quantised EM field, which is more complicated than bullet-like particles of light.

Yes, and you observe a double-slit interference pattern built up from many photons interacting with the screen. There is no observation at the slits is the point.


You could put different polarisers on each slit and then ... the double-slit interference pattern would be replaced by two single-slit patterns. This is the heart of QM. This is what is heuristically called "wave-function collapse". The coherent wave-function before the slits collapses into a superposition of different polarised states after the slits.

Not without absorbing it. A car, for example, can be observed without destroying it. If you observe a photon, then it's gone.

Thank you so much! This really clears a lot of stuff up, I guess I need to make some changes to my current set up of my Sunday's experiments!

 

[PeroK]

Summary:: I made experiments in my room and I think I am able to observe the wave function without its collapse, can anyone assist me?

You might be interested in this guy's video of his double-slit experiment (complete with theoretical explanations):

 

[ThiagoMNobrega]

You might be interested in this guy's video of his double-slit experiment (complete with theoretical explanations):

Wow! This video is amazing, I can't believe I didn't see this earlier! Thank you so much!

 

[ThiagoMNobrega]

You might be interested in this guy's video of his double-slit experiment (complete with theoretical explanations):

This video from the same guy on photon sieves is also really good, its been kinda of a wild ride to understand that photons are waves of electromagnetic radiation in a membrane-like cuboid¹ shape.. I'm still learning more about everything, this channel as been a life saver on the little free time I have to explore the subject.

1- Vol.8 No.2, February 2021, The Size and Shape of a Single Photon, https://www.scirp.org/journal/paperinformation.aspx?paperid=107462

 

[ThiagoMNobrega]

Also, I've played around a bit with photos inhencer to see how the results could look like before getting the next experiment setup