Solving the Mystery of Schrödinger's Cat and Its Qualified Observer

[Quinzio]

I have some hard times making senso out of this story.
To keep it short, I'll pose some questions.
Is it a mere thought experiment, or is possible to make it a real experiment ?

The state of the cat become certain when the cat is observed.

My question: what qualifies an observer ?
the observer must be a human ?
The cat itself is not an observer of the situation ?
The geiger counter is not an observer ?

What does it mean to observe ?
Does it need a conscious brain to make an observer ?

I can't believe of course the in physics you need a human brain to make a qualified observer.

The point is that I never saw this objection moved to the experiment.
Everyone takes for granted the the observer is a human who opens the box.

 

[comote]

Not everyone, in fact I think most have accepted that an outside environment can play the role of observer.

 

[Fredrik]

There was another thread about Schrödinger's cat recently. This is what I said there.

 

[arkajad]

You do not need an "observer" to perform the experiment. You need a reliable equipment that will do it for you for instance on Mars. After 100 years someone will find the data from the experiment and will analyze it. Perhaps a computer will analyze it and tell you the result by e-mail.

 

[Shawakaze]

Good question, but I think so long one can make computations one qualifies to be an observer. Take for instance instead of a human being one has a computer trying to monitor for life signs when the box is opened. If something can make a measurement of position and monentum, then I believe that thing qualifies to be an observer.

 

[arkajad]

Will you call voltmeter an "observer"? Of course, voltmeter can be observed, but it does not have to be. It will not change the voltage that it has registered.

 

[HallsofIvy]

Will you call voltmeter an "observer"? Of course, voltmeter can be observed, but it does not have to be. It will not change the voltage that it has registered.

But the whole point is that the voltmeter itself is an "observer". Looking at the volmeter will not change the voltage but putting a volmeter into a circuit does change the voltage in the circuit.

Any external mechanism that is put into a "closed" situation changes that situation and qualifies as an "observer".

 

[arkajad]

Voltmeter is a part of the experimental equipment. It is a macroscopic device that is not conscious. Calling it an "observer" is highly misleading. And it does not have to be put in place by a human being. It can be done by a robot. Consciousness can be as far away as you wish. Moreover, we are reading the data registered by rocks that were put in place by natural processes - no human consciousness involved whatsoever. The term "observer" can really be unnecessarily misleading.

 

[t_barlow]

I agree that "observer" is misleading, since when people hear "observer" they automatically think "sentient observer", hence we have crap like consciousness causes collapse and stuff. But I think it is OK to generalize the meaning of the word "observer" to include inanimate objects like voltmeters and experimental equipment, since when you do QM you do need to refer to whatever object/s (sentient or otherwise) is/are involved in the experiment, and they need a name... "observer" seems to be a reasonable word to use.

 

[arkajad]

Why not to use normal terms like "measuring device" or "detector"? They describe pretty well what is going on. Why to use confusing terms when there are well established, unambiguous and non-confusing terms? For what purpose?

 

[comote]

It's more general than that. Any interaction of the system with anything outside the system can be considered as an observer.

 

[arkajad]

It's more general than that. Any interaction of the system with anything outside the system can be considered as an observer.

Who defines where one system ends and the other begins? When we have an electron and a proton interacting via Coulomb forces is one observing the other? No, there is no observation. There is just an interaction. Not every coupling between systems is an "observation". If you call it an "observation" you are introducing your own terminology.

 

[comote]

Who defines where one system ends and the other begins? When we have an electron and a proton interacting via Coulomb forces is one observing the other? No, there is no observation. There is just an interaction. Not every coupling between systems is an "observation". If you call it an "observation" you are introducing your own terminology.

Actually I don't see why we couldn't call it an observation. If one could determine the properties of the electron by some other means then couldn't one then deduce properties of the proton. This seems to me to be a typical example of an indirect measurement.

This seems arbitrary but in a controlled situation couldn't one say that the system (and observer) is that which can be "effectively" isolated and accounted for while the environment is everything else.

Ultimately, the system is that which we intend to study. The observer is the means by which we intend to study it, and the environment is everything else.

 

[Upisoft]

Who defines where one system ends and the other begins? When we have an electron and a proton interacting via Coulomb forces is one observing the other? No, there is no observation. There is just an interaction. Not every coupling between systems is an "observation". If you call it an "observation" you are introducing your own terminology.

Correct me if I'm wrong, but I think an observation necessary requires energy change in the system. So, an electron and a proton interacting will not be considered observation, unless the electron decides to emit a photon...(or something else, but the photon emission is what happens most of the time)

 

[chis]

Reduction in information or relativity (closing the box) creates the disconnected state. Opening the box, smell, sound or heat would be an increase in information and for the sake of argument an observation. What provides this increase in information is irrelevant.
The double slit experiment reinforces this, as the destruction of the wave function is a mechanical process(optical sensor) and results in only indirect observation by the human involved, but never the less an increase in information and relativity.

 

[arkajad]

Correct me if I'm wrong, but I think an observation necessary requires energy change in the system.

Yes, as far as we know it requires energy exchange, but energy exchange is not important there. What is important is the transfer of information. We can measure a given quantity in many different ways using different measuring devices. Energy exchange will be different for each of these devices. Some of them may even destruct the measured object. Some will will be nondestructive measurements. But all of them should give us the same information - otherwise we would not be talking about different devices measuring, for instance, momentum.

We do not know if there exists a minimal energy change necessary for providing a given amount of a particular information about the system. Perhaps there is such a thing, or perhaps there is not. I don't know.

 

[gmax137]

Why not to use normal terms like "measuring device" or "detector"? They describe pretty well what is going on. Why to use confusing terms when there are well established, unambiguous and non-confusing terms? For what purpose?

Maybe the terms used were selected intentionally, because when Schrodinger devised the thought experiment, he was intending to show how absurd the Copenhagen interpretation was. Or how absurd he believed it to be. The experiment was intended to show that, if an atom can be in a superposition of two states, then so can a living being (the cat). Schrodinger's point is that as a cat cannot be both alive and dead, then the notion of an atom being in two states is also absurd. So I always thought that the little "eye" representing the observer was intentional, to highlight the 'mystic' connection to consciousness.

(EDIT) - I suggest you follow Frederik's link in post #3 above.

 

[Manik13]

Was Schrödinger's experiment ever performed for real or was it just a thought experiment?

 

[azdavesoul]

With all of this discussion about what would qualify as an “observer”, what about the cat? While it would be within the experiment, would it qualify as a conscious entity or as an internal element of the experiment?

 

[Upisoft]

To save you further question the cat is drugged and put to sleep. The only thing the cat is able to observe is the cat's equivalent of a pink elephant.

 

[arkajad]

And a mouse is the observer.

 

[Upisoft]

Nope, the elephants are afraid of mice... It is obvious there is no mouse.:rofl: