Elite Engineer

Is "Schrodinger's Cat" the wrong interpretation for Copenhagen Interpretation?

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I just recently found out that Schrodinger made his thought experiment as a criticism of wave function collapse, and tried to illustrate how absurd it was by saying a cat is both dead and alive simultaneously until observed. 

So when people try to explain uncertainty of something with Schrodinger's Cat, are they using the incorrect analogy to describe the moment of uncertainty?

 

~ee

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Any interaction is an 'observation', and causes wave function collapse.

And while this makes sense for a particle, or even a small group of particles like a molecule, it becomes absurd for a macroscopic object like a cat.

Don't take the interpretation too seriously

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Posted (edited)
5 hours ago, Elite Engineer said:

moment of uncertainty

 

Any spectroscopist will point out that this phrase is self contradictory in relation to the HUP.

Their direct evidence is the broading of spectral lines which they take to be the uncertaintly of the time taken for the electron transition/radiation emission.

Edited by studiot

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So, did Schrodinger create his analogy as an attack on quantum superposition, or was it an aide to help the laymen understand superposition on a macroscopic level? 

In short, did he agree or not?

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1 hour ago, Elite Engineer said:

So, did Schrodinger create his analogy as an attack on quantum superposition, or was it an aide to help the laymen understand superposition on a macroscopic level? 

In short, did he agree or not?

I will answer that when you write down the quantum mathematics of

 

a) A cat

b) Life

c) Death

 

:)

 

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Posted (edited)
On 12/4/2018 at 5:25 AM, MigL said:

Any interaction is an 'observation', and causes wave function collapse.

And while this makes sense for a particle, or even a small group of particles like a molecule, it becomes absurd for a macroscopic object like a cat.

Don't take the interpretation too seriously

Unless wave functions don't collapse and you simultaneously see a living and a dead cat when you open the box.

It is only absurd if you assume the cat is under superposition, while you are not. 

 

Edited by Bender

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The cat is in a probability superposition which is where the terminology originates until you open the box. Superposition is also a statistical mechanics terminology.

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Posted (edited)

Exactly.
A cat, composed of a billion, billion, billion particles cannot remain in superposition unless there are no interactions of  any of those particles.
Any macroscopic object, or animal, has to have a collapsed wave function.
Anything else is 'absurd'.

Edited by MigL

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Posted (edited)
On 4/12/2018 at 9:29 AM, Elite Engineer said:

So, did Schrodinger create his analogy as an attack on quantum superposition,

Yes. A coin is in a superposition of being both "heads" and "tails". Always. Even after you "call it" one or the other.

Edited by Rob McEachern
fix typo

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And that analogy fails because you can never collapse the coin's superposition.
There is no such thing as a single sided coin ( Mobius coin ?? ).

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Posted (edited)
3 hours ago, MigL said:

And that analogy fails because you can never collapse the coin's superposition.
There is no such thing as a single sided coin ( Mobius coin ?? ).

 Lol try to find that coin in your pockets.

 Lets take care here though. There is several differences between Superposition via Statistical mechanics and Superposition via QMs usage so this line of reasoning can vary depending on which interpretation of Superposition is being imposed.

Edited by Mordred

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7 hours ago, Rob McEachern said:

Yes. A coin is in a superposition of being both "heads" and "tails". Always. Even after you "call it" one or the other.

I'm a little confused by this. You mean "call it" while it's still spinning and the face of the coin hasn't been revealed?

So was Schrodinger saying, "No, photons can't exist in two different states (wave and particle) at the same time...that's just as ridiculous as a cat being both dead and alive at the same time"..and poof it became history. Did Schrodinger ever agree with the CI?

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Still looking for a response to my question.

 

Superposition means necessarily that you have some function describing some property or other to add up.

BTW, QM employs linear superposition.

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19 hours ago, MigL said:

you can never collapse the coin's superposition

Exactly my point. Superpositions only exist as a mathematical abstraction, and abstractions do not collapse.

12 hours ago, Elite Engineer said:

I'm a little confused by this.

So was the entire physics community. Schrodinger set out to develop a physical model of the trajectory of a particle, by using Fourier transform based superpositions, to describe a wavepacket, that "accompanies" a particle as it moves. But he eventually realized that while his equation provided a good computational model, for producing results, it resulted in an absurd physical model. Thus, he introduced his cat, in an attempt to convince people that one should never attempt to "interpret" a wavefunction as anything other than a useful computational device, which has no known relevance to a physical model, such as an actual propagating wave.

In the case of the coin, as in the case for spin and polarization, the state being observed, is not a property of the entity being observed. It is a property of how the observer decides to observe it - the observer will obtain different results, if the entity is observed from different "directions".  In other words, "calling" an entity "spin up" or "heads" is not a statement about the state of the entity. It is merely a statement about what the observer happens to "measure" when observing the entity from a particular direction.

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13 hours ago, Elite Engineer said:

So was Schrodinger saying, "No, photons can't exist in two different states (wave and particle) at the same time...that's just as ridiculous as a cat being both dead and alive at the same time"..and poof it became history. Did Schrodinger ever agree with the CI?

No. Wave and particle are not quantum states, thus there is no superposition possible.

20 hours ago, Rob McEachern said:

Yes. A coin is in a superposition of being both "heads" and "tails". Always. Even after you "call it" one or the other.

No, it isn't.

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21 hours ago, MigL said:

Exactly.
A cat, composed of a billion, billion, billion particles cannot remain in superposition unless there are no interactions of  any of those particles.
Any macroscopic object, or animal, has to have a collapsed wave function.
Anything else is 'absurd'.

Why?

One could also call it absurd that one group of particles can be in superposition (and macroscopic objects certainly can be), but when another particle joins in, it is suddenly no longer possible. Why can't the new interacting particle simply join the superposition?   

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1 hour ago, Bender said:

one group of particles can be in superposition

What do you mean by this?  Are you confusing superposition and coherence?

3 hours ago, Rob McEachern said:

In the case of the coin, as in the case for spin and polarization, the state being observed, is not a property of the entity being observed. It is a property of how the observer decides to observe it - the observer will obtain different results, if the entity is observed from different "directions".  In other words, "calling" an entity "spin up" or "heads" is not a statement about the state of the entity. It is merely a statement about what the observer happens to "measure" when observing the entity from a particular direction.

For the purpose of a statistics tossing experiment an ideal coin can be modelled as a Gaussian (orientable) surface with two sides.

But not all surfaces are Gaussian.

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12 hours ago, Bender said:

Why?

One could also call it absurd that one group of particles can be in superposition (and macroscopic objects certainly can be)  

Entangling a phonon state of a crystal is not the same thing as is being discussed here. Pop-sci articles play it a little fast and loose with the concept there. Objects are not entangled, states are. They buried the lede in the article, not mentioning that it's a phonon state that is entangled until the fifth paragraph. When you talk about entanglement, you always need to specify what state(s) is(are) entangled.

The purported state that is in a superposition in the Schrödinger's cat scenario is being alive and dead, which are not quantum states. It's part of the absurdity.

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12 minutes ago, swansont said:

The purported state that is in a superposition in the Schrödinger's cat scenario is being alive and dead, which are not quantum states. It's part of the absurdity.

 

Exactly +1

 

My question back along was designed to illustrate this.

Consider two bunches of particles, identical as far as our quantum theory can specify.

One runs around and catches mice

The other lies in a soggy smelly heap.

What is the (quantum) difference between these two. ie what quantum  number is different?

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Posted (edited)

Representing the cat as having two possible states is indeed absurd. It consists of a lot of particles and its state space is huge (with many, many different quantum numbers). However, roughly half of this state space will represent a dead cat, and roughly half represents a living cat.

Of course, in a real experiment, the box is not completely isolated, so the particles comprising the experimenter and his equipment (and the rest of the Earth) will be entangled with the inside op the box long before it is opened.

When discussing entangled particles, the focus is usually on two particles, because the entangled mess of larger systems is simply too complex.

As far as I know, there is no way of knowing whether the cat can be simultaneously dead or alive, but if it is, it is on different states of our entire planet.

Edited by Bender

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6 minutes ago, Bender said:

(with many, many different quantum numbers).

With respect, that's waffle and I'm only asking for the one quantum number that is (allegedly)different.

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Why should there be only one that is different? 

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Posted (edited)
1 hour ago, Bender said:

Why should there be only one that is different? 

Where did I say only one has to be different?

Why could there not be many different ones, if there are any at all.

But I have yet to see any hard evidence or mathematics to back up such an allegation.

And if there are many, then citing one will be sufficient.

 

Quote
4 hours ago, studiot said:

I'm only asking for the one quantum number that is (allegedly)different.

 

BTW how many different types quantum number do you think you need to define the quantum state?

Surely there are only a handful?

 

Edited by studiot

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