# Thread: The measurement problem: A new idea.

1. Traditional quantum mechanical interpretations, often involve some type of measurement to cause a wave function to collapse. Other theories range from the many worlds to pilot wave theory. However what if they are all wrong, what if the answer has been staring us in the face the entire time.

The measurement problem or wave function collapse, could boiled down to one simple thought experiment. Schrodingers Cat. To remind you the experiment involves a cat, being placed in a box, with a radioactive substance, that has 50% chance of either decaying or not decaying. If it decays it will be detected by a Geiger counter, and by a relay a hammer will be released, that will smash a flask of poison gas, thus killing the cat.Now according to quantum mechanics, the substance has both decayed and not decayed at the same time, as it is probabilistic event, thus translating to a cat that is dead and alive at the same time. This is an obvious paradox.

As mentioned earlier other interpretations have suggested that it is the measurement that causes collapse. However what if it is the classical nature of the hammer used smash the flask that actually caused the collapse. This new idea states, that a wave function collapses, when a quantum event will have a direct effect on a decision with classical object. According to this idea, when objects get to a certain size quantum laws will begin to fade away and will be replaced by classical laws. Unlike other theories, such as decoherence that states that objects behave classically, due to a particle interacting with it's environment, this theory says that for some reason different rules will just apply. Now the hammer, in the thought experiment, is a classical object and classical objects do not exist in a state of superposition, so the wave function will collapse to one state in order to allow the object to behave in a classical manor, it can no longer exist in superposition. So in short the wave function collapses when it is going have a direct impact on a decision made in the classical world, and collapses to defined location in order to allow that classical event to happen, because if it was still in superposition when the chain of events lead to the hammer smashing the flask of poison, it would not behave classically since classical objects have defined location so the particle in this circumstance will need a defined location in order for the defined event in the classical world to happen.

Furthermore this can apply to other scenarios, such as the double slit experiment, because during the experiment there will be some point down the line in which it will have an impact on a classical object.

Please tell me what you think of my idea. It would be very appreciated.

2.

3. Originally Posted by JJ2012
Please tell me what you think of my idea. It would be very appreciated.
If you read carefully what you've proposed, you will see that you have invoked magic to "explain" something that has explanations (but ones you dislike). You've simply declared by fiat that something happens, and that's that.

I agree fully that "wave function collapse" is unsatisfying -- a great many physicists have pointed out its arbitrariness, and the difficulty of having fully linear dynamical equations rule the atoms up until the moment of measurement, only to have a fundamentally nonlinear operation -- collapse -- then take over. But your proposal has the same problem.

The decoherence-based explanation that you disfavour does not suffer from this problem, and also allows a full accommodation of the correspondence principle, allowing one to scale up from the quantum to the macroscopic realm in a continuous manner. I have no data to back up my assertion, but I get the sense that this explanation is currently favoured by most practising physicists. Your proposal seems to be, essentially, decoherence-based (perturbation of a quantum state by interaction with the macroscopic world), while rejecting that characterisation by invoking the word "collapse". Perhaps you could say more to clarify what the distinction is.

The other interpretation you reject -- Everett's MWI -- also avoids having to invoke collapse. I would guess that MWI, or some variant thereof, is also accepted as plausible by a growing percentage of physicists, while the Copenhagen interpretation is decreasingly thought of as "the right way" to think about the measurement problem. But again, I have no polling data to support my assertion. That's just the sense I get from listening to conversations at conferences and with my colleagues.

4. Originally Posted by JJ2012
However what if it is the classical nature of the hammer used smash the flask that actually caused the collapse.
Beside the point - the hammer doesn't do anything until the decay occurs.
In other words we could leave the cat out altogether and simply consider whether or not the hammer falls - it both does and doesn't1.
Likewise one could equally say that it was the "fault" of the Geiger counter - it did and it didn't detect the decay.

Now the hammer, in the thought experiment, is a classical object and classical objects do not exist in a state of superposition
Um, and a cat isn't a classical object?

1 Well, "it does and it doesn't" in exactly the same way that "the cat is both dead and alive" - i.e. not really.

Yes the cat is a classical object the hammer was simply the first classical decision it was going to encounter. So the fate of the cat was determined when the quantum system encountered the first classical decision

6. Originally Posted by JJ2012

Yes the cat is a classical object the hammer was simply the first classical decision it was going to encounter.
So the Geiger counter isn't classical?

7. Wasn’t the whole point of the thought experiment to show that the cat, hamme, Geiger counter (and all the “classical” components) would not be in a state of superposition? So, in a sense, Schroedinger was on the same side as the OP.

Of course, it is an argument from incredulity and so not very combing. It also doesn’t answer the question of what distinguishes quantum-level events from classical. (And neither does the OP.)

8. Originally Posted by Strange
Wasn’t the whole point of the thought experiment to show that the cat, hamme, Geiger counter (and all the “classical” components) would not be in a state of superposition?
Well it was focussed on the cat - the OP seems (to me) to be claiming/ thinking that the "switch-over" is at the hammer rather than the cat1 - but the "experiment" could have just as easily stated that the Geiger counter both does and does not register2.

1 To my mind neither the cat nor the hammer (nor the poison) were "needed".
2 But that's not as obviously absurd as a cat being alive and dead at the same time, nor as likely to be as "emotionally popular"... If it were "Schrodinger's Counter" how much press would it have been given?

9. Thank you very much for responding,

Firstly 'magic' has not been invoked. Niels Bohr's, Copenhagen interpretation involved the concept that the act of measurement 'forces nature to decide', a definite location or state. My argument is similar, classical laws are capable of forcing nature to decide. This is not magic. It is when a quantum state becomes entangled, as in Schrodinger's cat, that the nature of classical objects forces nature to decide in order to allow for an event in the classical world to manifest in a classical manor.

As for decoherence, it does not fully explain collapse, but rather information leaking into the environment, when the environment carries out a measurement.

Furthermore recent polls have shown that 42% of physicists support the Copenhagen interpretation, compared to 18% supporting MWI, with the rest supporting a variety of different interpretations.

10. Originally Posted by JJ2012

Yes the cat is a classical object the hammer was simply the first classical decision it was going to encounter. So the fate of the cat was determined when the quantum system encountered the first classical decision
I think you may be making a false dichotomy between "quantum" and "classical". I have always understood quantum mechanics merges into classical mechanics seamlessly, as the scale increases relative to the magnitude of Planck's Constant. If so I do not see how you can make a distinction.

11. Originally Posted by exchemist
Originally Posted by JJ2012

Yes the cat is a classical object the hammer was simply the first classical decision it was going to encounter. So the fate of the cat was determined when the quantum system encountered the first classical decision
I think you may be making a false dichotomy between "quantum" and "classical". I have always understood quantum mechanics merges into classical mechanics seamlessly, as the scale increases relative to the magnitude of Planck's Constant. If so I do not see how you can make a distinction.
Can classical phenomena be said to emerge from quantum phenomena?

Is there any sense in which quantum phenomena are more fundamental than classical phenomena?

(Yes I was under the impression that the transition was seamless and that anything was possible ,such as the spontaneous appearance of a second moon followed or not followed by its disappearance,this only being vanishingly improbable in the lifetime of an enormous number of lifetimes of the current universe:randomness ruling even in the "classical realm")

12. There are many interpretations. Each different interpretation has different ideas about distinguishing the classical realm and the quantum realm. for instance the many worlds interpretation, and pilot wave and the de-broigle-bohm, interpretation state that particles always behave classically and there quantum behaviour are as a result of either a particle 'hopping' along a wave or all of the possible outcomes in a quantum event taking place actually happening. If these theories can have different interpretations of the classical world, why can't this one?

13. There are many interpretations. Each different interpretation has different ideas about distinguishing the classical realm and the quantum realm. for instance the many worlds interpretation, and pilot wave and the de-broigle-bohm, interpretation state that particles always behave classically and there quantum behaviour are as a result of either a particle 'hopping' along a wave or all of the possible outcomes in a quantum event taking place actually happening. If these ideas can have different interpretations of the classical world, why can't this one?

14. dupe post -- having trouble with the editing script.

15. Originally Posted by JJ2012
Thank you very much for responding,

Firstly 'magic' has not been invoked. Niels Bohr's, Copenhagen interpretation involved the concept that the act of measurement 'forces nature to decide', a definite location or state.
My working definition of "magic" here is "the production of a result by an undefined -- and perhaps undefinable -- process." The critics of CI focus their criticism on this magic. Everett was motivated to develop his MWI precisely to avoid invocation of this magic.

My argument is similar, classical laws are capable of forcing nature to decide. This is not magic.
Whatever you wish to call it, it's the same magic. You claim to have solved a problem, but you have only moved it to a different location. What is this forcing? It appears to be simply alternative language to "then magic happens, and a specific reality emerges." To this you've only added some language about classical vs. quantum domains, but by invoking only the words, you haven't solved anything that I can see. In fact, precisely because you've left undefined what is meant quantitatively by the classical-quantum boundary, you've actually introduced a new mystery.

It is when a quantum state becomes entangled, as in Schrodinger's cat, that the nature of classical objects forces nature to decide in order to allow for an event in the classical world to manifest in a classical manor.
Or classical manner in the manor of science. That aside, once again, merely alluding vaguely to the "nature of classical objects" forcing "nature to decide" doesn't solve anything at all. I could, for example, simply say that "the nature of all objects is to behave in the way they ought to behave". That last phrasing contains pretty much the same explanatory power as the previous one.

As for decoherence, it does not fully explain collapse, but rather information leaking into the environment, when the environment carries out a measurement.
That's still being debated. One thing that decoherence does uniquely allow us to do is to track, in a continuous manner, how state evolves as the number of interacting elements increases. There's no artificial boundary between quantum and classical; just a progressive (and precipitous) increase in decoherence. Thus one proceeds to the classical limit without any arbitrariness. The CI, and your interpretation, suffer from this same defect of arbitrariness and lack of definition. Magic, in other words.

Furthermore recent polls have shown that 42% of physicists support the Copenhagen interpretation, compared to 18% supporting MWI, with the rest supporting a variety of different interpretations.
There have been many polls. I don't put a whole lot of stock in them because of poor sampling methodologies typically used; these are generally quite informal things. Just changing the wording of the question can produce very different outcomes. Please cite your source for your numbers. I would be very surprised if that poll had been conducted with any more rigour than many that preceded it.

16. dupe post

17. Firstly, even though the method of collapse provided by CI or collapsing when entangled with a classical object may not provide a detailed explanation of how collapse occurs does not mean it is incorrect. Before Einstein Newton had his theory of gravity, but there was no mechanism for gravity, then Einstein came along with his general theory of relativity and provided that mechanism.

furthermore there are problems with the many worlds interpretation and the building of the classical world. The mathematics behind quantum theory, suggests that quantum objects fuzzy(in the form of the Schrodinger equation), not well defined states as suggested by Everrett. different states are overlapping, in the form of a wave function, so if the many worlds interpretation is correct then we should see these worlds blurring together. So if the many worlds interpretation is correct then we should observe a smeared out world blurred together, with others. But instead we see a world that has a well defined location, which in my opinion is due to collapse occurring either by quantum systems becoming defined when interaction with classical situations, or by measurement.

18. Originally Posted by JJ2012
Firstly, even though the method of collapse provided by CI or collapsing when entangled with a classical object may not provide a detailed explanation of how collapse occurs does not mean it is incorrect. Before Einstein Newton had his theory of gravity, but there was no mechanism for gravity, then Einstein came along with his general theory of relativity and provided that mechanism..
Yes, that's all fine and good to preserve some slender thread of hope, but "not yet proven wrong" is quite a long distance from "and therefore correct." Citing successful theories, like GR, is to engage in a form of confirmation bias. One could cite many more examples where the story did not end happily for the proponent. But that's really irrelevant, isn't it? Why desperately cling to polls? The fact remains that your "new idea" is actually pretty much the same as the "old idea." It invokes precisely the same magic. Your "explanation" is in the category of "not even wrong"; there's no specificity, and thus no testability. It thus has the same weakness as CI's magical wavefunction collapse upon "measurement". You have not addressed the issues raised. I gather that you'd prefer that we not offer critiques. If that's so, just say so.

19. I'm just responding accordingly to criticism. I like your criticism, thank you. You seem agitated, sorry if this some how offended you.

20. Originally Posted by JJ2012
I'm just responding accordingly to criticism. I like your criticism, thank you. You seem agitated, sorry if this some how offended you.
Not agitated, but your responses don't address the criticism. You either repeat your claim, or attempt to deflect attention to the other interpretations. I've seen that tactic too many times here, so I've built up antibodies. Many with a "novel idea" post here claiming that they invite criticism, but actually react quite badly to any. The burden of proof is not on us to disprove your idea. It's on the claimant to support his or her assertion. But your posts are not reflective of that protocol. I know it's hard to hear that your baby might not be quite as beautiful to others as it is to you, but that's the nature of scientific theories.

21. I still interpret the state of the cat as unknown in the classical sense, lack of knowledge. The uncertainty is with the radioactive decay.
The collapse is gaining enough info to decide, a classical process.