Why does a the Wave Function collapse?

[mpolo]

Why does a wave function collapse when we observe a particle? I would like to know why something that is in Super Position suddenly chooses a particular position when observed? If something is in all positions or states. How does the particle choose a particular state? What is the decision making process?

 

[Trollfaz]

This is still an unknown process: Why measurement collapses the superposition. This is called the Measurement Problem. Many theories are put forth to explain it, such as the Many Worlds Theory, Decoherence, etc.

For all I know "observe" has nothing to do with humans looking. A human is not necessary to collapse the superposition. Anything can perform a measurement, be it a human, a chimp, a cat, a virus, a detector, an atom, an electron, you name it.

 

[mpolo]

Could we say this is the cause? Super position works by the power of influencing the course of events by using a mysterious or supernatural force? Are there any other explanations besides the Many Worlds and Decoherence?

 

[PeterDonis]

Why does a wave function collapse when we observe a particle?

Collapse is an interpretation of QM; it is not part of the basic theory. So this question is not a question about physics, it's a question about interpretation, which cannot be resolved by experiment since all interpretations make the same predictions for all experiments.

 

[PeterDonis]

Super position works by the power of influencing the course of events by using a mysterious or supernatural force?

Please review the PF rules on personal speculation.

 

[mpolo]

I think that Decoherence is the most likely explanation but there is still the problem, that Decoherence does not claim to provide a mechanism for the actual wave function collapse; rather it puts forth a reasonable mechanism for the appearance of wavefunction collapse. So I guess I am still stuck with a mystery. So to be clear, I am asking about the interpretation or meaning of the wave function collapse?

I had to read this statement many times.

it's a question about interpretation, which cannot be resolved by experiment since all interpretations make the same predictions for all experiments.

It seems to me that there can only be one correct Interpretation for any mathematical formula or model. Are you saying we cannot prove which interpretation is correct by experiment? That I think is what I am trying to understand here. Which is what is the actual mechanism that causes wave function collapse.

 

[PeterDonis]

I think that Decoherence is the most likely explanation

Decoherence is not interpretation dependent, and yes, it is the current best explanation we have in the context of basic QM (i.e., without choosing any interpretation).

there is still the problem, that Decoherence does not claim to provide a mechanism for the actual wave function collapse

That's not a problem, it's just a fact.

It seems to me that there can only be one correct Interpretation for any mathematical formula or model

Then you really, really need to take the time to learn about the different interpretations of QM, so you will see concrete examples of different interpretations of the same mathematical model.

Are you saying we cannot prove which interpretation is correct by experiment?

Yes, because all interpretations of QM make exactly the same predictions for all experiments. This is because all interpretations use the same mathematical model to make predictions.

what is the actual mechanism that causes wave function collapse.

And I've already explained why this question doesn't have an answer.

 

[PeterDonis]

The OP question has been answered. Thread closed.

 

[fresh_42]

It seems to me that there can only be one correct Interpretation for any mathematical formula or model.

This cannot be correct, because a mathematical formula or model is made to describe a certain process and the variables to represent a certain quantity. An experiment or measurement is usually an example which tests the validity of the model. An interpretation is per se an attachment of meaning, which humans provide to fit their individual perception of nature. It cannot be tested, because it isn't part of the model, only part of a verbal description of this model. The model itself has no meaning, resp. interpretation beside the dependencies of quantities.

Are you saying we cannot prove which interpretation is correct by experiment?

How would you distinguish whether $\dot{x}(t)=c$ is interpreted as speed or as distance. They are two different ways to describe the formula. Mathematically it is only a straight, and physically a uniform movement. You cannot say that one interpretation is correct and the other is not. Both rely on the same formula, make the same predictions and experiment proves both to be true. I admit it is a bit of a poor example, but the mechanism of interpretation is the same. I recently counted on how many ways a derivative can "interpreted" mathematically. I've found ten different environments, all describing one formula from different perspectives.