quantum-mechanical collapse

[Itoero]

Is the collapse of the wave function a real physical process or an epiphenomenon due to the Uncertainty principle?

[Strange]

It depends which interpretation you choose: https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics

Science doesn't deal with what "really" happens, just what we can observe. It is your philosophical choice as to whether it is real or not. (And you would also need to define what you mean by "real".)

[Itoero]

6 hours ago, Strange said:

Science doesn't deal with what "really" happens, just what we can observe. It is your philosophical choice as to whether it is real or not. (And you would also need to define what you mean by "real".)

So until observed otherwise(possibly by improved measuring devices), we can't know if it's real or not? Like Schrodinger's cat.

In Physics, I consider something 'real' when there is sufficient or indisputable scientific evidence.

Edited September 23, 2017 by Itoero

[swansont]

15 minutes ago, Itoero said:

So until observed otherwise(possibly by improved measuring devices), we can't know if it's real or not? Like Schrodinger's cat.

In Physics, I consider something 'real' when there is sufficient or indisputable scientific evidence.

Is real "physically existing"? Or is it "not fake"?

 

[Strange]

2 hours ago, Itoero said:

So until observed otherwise(possibly by improved measuring devices), we can't know if it's real or not? Like Schrodinger's cat.

That's not really what I meant. I just mean that science can't tell us about the "true nature of reality" (if there is any such thing). It can only describe things we can measure.

Quote

In Physics, I consider something 'real' when there is sufficient or indisputable scientific evidence.

OK. So you don't mean any sort of reality beyond what we see and measure. (A sort of naive realism.) That's fine. The trouble is, that does mean you have to keep adjusting your idea of what is "real" as science advances. And I think some people would say that "reality" shouldn't change like that, it should be independent of our theories.

[Mordred]

"Artifacts of a metric" being related 

[Itoero]

14 hours ago, Strange said:

OK. So you don't mean any sort of reality beyond what we see and measure. (A sort of naive realism.) That's fine. The trouble is, that does mean you have to keep adjusting your idea of what is "real" as science advances. And I think some people would say that "reality" shouldn't change like that, it should be independent of our theories.

I said: "In Physics".In hard sciences it's important that people's idea of what is 'real' is adjusted due to scientific evidence. That's necessary for the evolution of science.

[Itoero]

16 hours ago, Strange said:

That's not really what I meant. I just mean that science can't tell us about the "true nature of reality" (if there is any such thing). It can only describe things we can measure.

That's true but if wave collapse is a physical process according to our reality then extra knowledge and improved measuring devices will (hopefully) show that. The same goes for when its not a physical process.

[Strange]

1 hour ago, Itoero said:

That's true but if wave collapse is a physical process according to our reality then extra knowledge and improved measuring devices will (hopefully) show that. The same goes for when its not a physical process.

That would mean having a different theory, with different predictions, for the Copenhagen Interpretation and, say, the Many Worlds Interpretations. As they are just different descriptions of the same theory, there isn't (currently) any way to distinguish them.

[Eise]

On 9/23/2017 at 1:05 PM, Itoero said:

Is the collapse of the wave function a real physical process or an epiphenomenon due to the Uncertainty principle?

Two questions:

1. Are these the only two possibilities? I.e. when one of them is false, the other one is automatically true?
2. Can you explain what you mean with 'the collapse of the wave function is an epiphenomenon due to the Uncertainty principle'?

[Mordred]

The answer to number two is no.

Collapse of any wavefuction entangled or not is due to interference ( either constructive or destructive) of an interaction with said wavefunction.

Uncertainty is not an interference, it is an uncertainty of the measurement itself not an interference

[swansont]

3 hours ago, Itoero said:

That's true but if wave collapse is a physical process according to our reality then extra knowledge and improved measuring devices will (hopefully) show that. The same goes for when its not a physical process.

For the wave function collapse to be a physical process, doesn't the wave function have to be a physical entity? Is it?

[Itoero]

On ‎24‎-‎9‎-‎2017 at 5:30 PM, Eise said:

Can you explain what you mean with 'the collapse of the wave function is an epiphenomenon due to the Uncertainty principle'?

Wave particle duality is about wave function collapse. The wave behavior disappears/collapses when one tries to determine the particle's path. This paper shows how wave particle duality is quantum uncertainty.https://arxiv.org/pdf/1403.4687.pdf

"The connection between uncertainty and wave-particle duality comes out very naturally when you consider them as questions about what information you can gain about a system. Our result highlights the power of thinking about physics from the perspective of information,"

[Chopsticks]

What we know: Make a bunch of identical particles, send them through your test setup, and measure their position on the far end. The shape of that distribution will depend on the probability function.

Now, get rid of all particles except at one position (pinhole is a typical method). Put a position detector past the pinhole. You'll get a particle distribution of a spherical probability wave emanating from the pinhole. 

Before the pinhole you have one probability distribution. After the pinhole there is a different distribution. So, there was a waveform collapse at the pinhole. (I suspect I'm mashing two different experiments together, but should still be true). Whether that collapse is physical depends how you define physical.

My hypothesis is that, whatever "collapse " ends up being, it will be the point where QM and relativity end up meeting. QM interaction where one thing has "enough" mass or something.

Edited September 25, 2017 by Chopsticks
Text pasted too bigbig

[swansont]

1 hour ago, Itoero said:

Wave particle duality is about wave function collapse. The wave behavior disappears/collapses when one tries to determine the particle's path. This paper shows how wave particle duality is quantum uncertainty.https://arxiv.org/pdf/1403.4687.pdf

"The connection between uncertainty and wave-particle duality comes out very naturally when you consider them as questions about what information you can gain about a system. Our result highlights the power of thinking about physics from the perspective of information,"

...in a specific application, namely interferometers. That does not mean that this is generally true.

[Itoero]

On ‎25‎-‎9‎-‎2017 at 9:48 PM, swansont said:

...in a specific application, namely interferometers. That does not mean that this is generally true.

Perhaps, but there is more that shows for example how quantum non-locality is due to quantum uncertainty. It seems that uncertainty induces nonlocality.

This is a ' continuation' on that paper on wave particle duality:https://arxiv.org/pdf/1512.09081.pdf

quantum error correction:https://arxiv.org/pdf/1605.01420.pdf

quantum nonlocality: https://arxiv.org/pdf/1312.0080.pdf    https://arxiv.org/pdf/1004.2507.pdf

second law of thermodynamics: https://arxiv.org/pdf/1205.6894.pdf

Something I read "It's possible to write equations that capture how much can be learned about pairs of properties that are affected by the uncertainty principle. Coles, Kaniewski and Wehner are experts in a form of such equations known as 'entropic uncertainty relations', and they discovered that all the maths previously used to describe wave-particle duality could be reformulated in terms of these relations."https://www.sciencedaily.com/releases/2014/12/141219085153.htm

Edited September 28, 2017 by Itoero

[Dubbelosix]

On 23/09/2017 at 0:05 PM, Itoero said:

Is the collapse of the wave function a real physical process or an epiphenomenon due to the Uncertainty principle?

The collapse of a wave function, is ... widely considered as a random process, though technically-speaking, the evolution of a wave function is entirely deterministic. It is true, the wave behaviour disappears during observation of the system - consider the atom which is shot at with a photon, it's position can be known but with uncertainty in the momentum. Is the linking of the UP with the wave function collapse a surprise?

 

Well no, the process of inducing uncertainty in the system, requires a definition of observing the system in some way. Obviously then, a collapse is on the table. They are two sides of a phenomenon from the same source of physics. 

 

 

Edited September 30, 2017 by Dubbelosix

[swansont]

11 minutes ago, Dubbelosix said:

The collapse of a wave function, is ... widely considered as a random process,  

It is?

[Dubbelosix]

1 hour ago, swansont said:

It is?

Yes.. but I would also like to add, that I don't personally believe that the collapse is random.

 

Though a wave function may have a high probability of collapsing to the most likely outcome, but because this is not a set rule (ie. the wave function can collapse to lower probability states), then the wave function is considered (in this case) as not deterministic.

 

I took the liberty to find you a paper, swansont.

https://arxiv.org/pdf/1607.06438v1.pdf

[swansont]

1 hour ago, Dubbelosix said:

Yes.. but I would also like to add, that I don't personally believe that the collapse is random.

 

Though a wave function may have a high probability of collapsing to the most likely outcome, but because this is not a set rule (ie. the wave function can collapse to lower probability states), then the wave function is considered (in this case) as not deterministic.

 

I took the liberty to find you a paper, swansont.

https://arxiv.org/pdf/1607.06438v1.pdf

It was unclear to me what was thought to be random. The time of the collapse, or the state to which it collapses.