Exploring the Role of Decoherence in Perceiving Superpositions

[durant35]

I was reading a M. Schlosshauer paper on decoherence and he does an effort in explaining perception by decoherence, in a example od an observer perceiving a spatial superposition. Here is the link of the paper:
http://arxiv.org/abs/quant-ph/0506199

Now my question is wouldn't the decoherence occur even before the light hit the observers eye unlike Schlosshauers example where he states that the retinal cells are in a superpositionThanks in advance.

 

[Jilang]

Isn't it rather that the perception is one cause of the decoherence? Perhaps I am reading it differently!

 

[bhobba]

Now my question is wouldn't the decoherence occur even before the light hit the observers eye

As I have explained many many times objects in the everyday common-sense world are decohered to have an actual position regardless of perception by an observer.

Thanks
Bill

 

[durant35]

As I have explained many many times objects in the everyday common-sense world are decohered to have an actual position regardless of perception by an observer.

Thanks
Bill

I understand that. I was wondering about a hypotethical where we actually achieved the spatial superposition and after the light hit the object which is in two locations where would the decoherence regarding our perception happen? Or our perception practically wouldn't even work because it would be too cold to keep us alive?

 

[bhobba]

which is in two locations where would the decoherence regarding our perception happen?

Its got nothing to do with perception. The photons would decohere it and give it an actual position.

Thanks
Bill

 

[durant35]

Its got nothing to do with perception. The photons would decohere it and give it an actual position.

Thanks
Bill

Then why did Schlosshauer give that particular example? Can you please check the document I posted (maybe you already have since I know you're a huge fan of his).
I don't really understand what he is referring to since he mentions superpositions of retina cells etc.

Thanks

 

[bhobba]

Then why did Schlosshauer give that particular example?

One can place the classical quantum cut anywhere. Decoherence says you place it just after decoherence. He is looking at what happens if you don't and place it in the brain. Its interesting but IMHO just that - it leads to a very weird view of the world if you do.

I suggest before delving into such exotica you learn some of the formalism of QM.

Thanks
Bill

 

[durant35]

Its got nothing to do with perception. The photons would decohere it and give it an actual position.

Thanks
Bill

So the light that reflects of the object would actually transmit information to our eyes about the decohered stated of the object that is in one position rather than the past state of the object that was in two locations?

 

[bhobba]

the object that was in two locations?

You need to learn some QM. Things are not in two locations.

Light that reflects of the object interacts with it decohering it so it has an actual position.

Thanks
Bill

 

[durant35]

You need to learn some QM. Things are not in two locations.

Light that reflects of the object interacts with it decohering it so it has an actual position.

Thanks
Bill

I know I need to learn it, we agreed on that. I was referring to the example of Schlosshauer where he clearly (but hypotethically) mention an object in two spots. So the light interacts with it giving it a definite position and then the light transmits information about the decohered object about it to our eyes. Right?

 

[bhobba]

mention an object in two spots.

If he said that he is wrong.

One can place the classical quantum cut anywhere. Decoherence says you place it just after decoherence. He is looking at what happens if you don't and place it in the brain. Its interesting but IMHO just that - it leads to a very weird view of the world if you do.

Its what I said before. If that isn't clear then I can't explain it better.

Thanks
Bill

 

[durant35]

If he said that he is wrong.
Its what I said before. If that isn't clear then I can't explain it better.

Thanks
Bill

The part you mentioned is clear, of course. The part I don't understand is the issue can we detect a superposition with our senses. And yes, I know, that in ou everyday common sense world there are no quantum effects but if we went to the lab and put an object in an excited state would the light transmit the information about the interference to our eyes before it decoheres the object our would the propagation of light to our eyes occur after the object decoheres? Thats my question.

 

[bhobba]

The part you mentioned is clear, of course. The part I don't understand is the issue can we detect a superposition with our senses.

Again you are misunderstanding what a superpoition is - every state is in superposition.

Hopefully you mean a superposition of position. No we cant.

Thanks
Bill

 

[durant35]

Again you are misunderstanding what a superpoition is - every state is in superposition.

Hopefully you mean a superposition of position. No we cant.

Thanks
Bill

Misuse of terms on my side, I apologize. I meant interference. Why we can't, physically speaking?

 

[bhobba]

Why we can't, physically speaking?

Your eyes are like the screen in a double slit - it registers a definite position.

Thanks
Bill

 

[durant35]

Your eyes are like the screen in a double slit - it registers a definite position.

Thanks
Bill

Ok, thanks, that's a great analogy. But of course that doesn't change the fact that the object will decohere to a definite outcome long before we even have a chance to observe it and that the photons will send the information not about the interference, but about the decohered object, right? So as you say, after decoherence everything is classical, and in an attempt to see interference we neccessarily need to interact with light and that light would 'collapse' the object and it wouldn't send any information about the interference. Please correct my reasoning if I am wrong