Knowledge and information in the physical world

[geordief]

I understand that the Uncertainty Principle is considered as embedded in Nature and is not to be considered as a simple limit on the capabilities of our experimental observations.

Is there a sense (or is it true) whereby the physical participants in a quantum interaction hold information as to the outcome of any interaction? ( and that this information is also subject to the Uncertainty Principle)

 

[Paul Colby]

What's a "physical participant" in a quantum interaction?

As far as I know, and this may not be very far, the basic rules of QM provide no information as to when a given isolated atom or nucleus will decay. It only provides decay rates of collections of such systems. So, is there a means for one person to know in advance the decay time of an isolated atom? Is this even part of the theory?

 

[PeroK]

I understand that the Uncertainty Principle is considered as embedded in Nature and is not to be considered as a simple limit on the capabilities of our experimental observations.

Is there a sense (or is it true) whereby the physical participants in a quantum interaction hold information as to the outcome of any interaction? ( and that this information is also subject to the Uncertainty Principle)

Can you state the uncertainty principle?

 

[geordief]

I understand that the Uncertainty Principle is considered as embedded in Nature and is not to be considered as a simple limit on the capabilities of our experimental observations.

Is there a sense (or is it true) whereby the physical participants in a quantum interaction hold information as to the outcome of any interaction? ( and that this information is also subject to the Uncertainty Principle)

What's a "physical participant" in a quantum interaction?

As far as I know, and this may not be very far, the basic rules of QM provide no information as to when a given isolated atom or nucleus will decay. It only provides decay rates of collections of such systems. So, is there a means for one person to know in advance the decay time of an isolated atom? Is this even part of the theory?

Thank you for the replies

By "physical participant" I mean each of the physical objects that contribute to the interaction.
Perhaps you understood me to imply some human or sentient involvement in the interaction?

My use of the word "participant" may have been ill judged but I was not thinking of any observer at all- just a physical interaction which ,to my understanding requires at least two "physical entities" (I may revise that if spontaneous emissions only require 1 physical object)

@PeroK my understanding of the Uncertainty Principle (UP?) is probably pretty basic in that I understand it to mean,in the first instance that the positional accuracy of an object is in inverse proportion to the accuracy of its momentum and that both cannot be measured with complete accuracy at the same time.

 

[Paul Colby]

By "physical participant" I mean each of the physical objects that contribute to the interaction.

So, if I said the answer is no, could you provide a counter example?

 

[geordief]

So, if I said the answer is no, could you provide a counter example?

Do you mean ,"no that the quantum objects do not hold information that determine the outcome of the interaction" or that "no,that that information is subject to the Uncertainty Principle"?

If you mean the former (and by extension the latter also) is my scenario not all encompassing and doesn't it involve all possible quantum interactions?

What could be a counter example in that case ?One where a quantum object contained no information or where the outcome of an interaction could be precisely determined?

The gist of my question is whether of not one can consider the objects taking part in quantum interactions as somehow being "observers" of each other.

Do they carry information about themselves and does this information somehow blend with that of the other quantum object when they interact ?

I am probably very wide of the mark but do you see the question I am trying to ask?

In a Classical sense this is like when I go to the shop and ,in my mind I want to buy milk but the shop is out of milk. The information that I have about myself (I have the money) meets the information the shop assistant has(we have no milk) leading to an outcome yet to be unveiled!

So a Classical interaction...

 

[PeterDonis]

@geordief your questions aren't really answerable because you're using vague ordinary language instead of precise math. Words like "information" and "observer" don't have single precise meanings.

One thing we can say, however, is that this...

In a Classical sense this is like when I go to the shop and ,in my mind I want to buy milk but the shop is out of milk. The information that I have about myself (I have the money) meets the information the shop assistant has(we have no milk) leading to an outcome yet to be unveiled!

...does not work. We know that because quantum objects violate the Bell inequalities. That means that the outcomes of quantum measurements cannot be just a matter of revealing pre-existing properties that were determined in the past of the measurement (in your example, the pre-existing properties would be that you want milk and the shop is out of milk).

In other words, quantum objects do not obey all of your classical intuitions. Does that answer your question?

 

[Paul Colby]

Do you mean ,"no that the quantum objects do not hold information that determine the outcome of the interaction"

If that's your question then, yes. Quantum objects don't hold information that determines the outcome of the interaction was my test assertion.

A possible counter example is given by entangled particles. Entangled particles occupy a multi particle state which correlate their subsequent measurements. This correlation isn't subject to uncertainty in any universal way I'm aware of.

 

[PeterDonis]

This correlation isn't subject to uncertainty in any universal way I'm aware of.

That's correct, it isn't.

In technical terms (which might be a little much given the thread level, but I'll say it anyway), the uncertainty principle in QM arises from the fact that certain pairs of operators do not commute--for example, position and momentum of the same particle in the same direction, or spin operators for the same particle in different directions.

But the correlation between two particles that are entangled involves operators that do commute--in the usual case, spin operators on both particles. So there is no uncertainty principle involved in such correlations; they can be 100% exact, and in principle this could be confirmed to arbitrary accuracy with measurements.

 

[geordief]

@geordief your questions aren't really answerable because you're using vague ordinary language instead of precise math. Words like "information" and "observer" don't have single precise meanings.

One thing we can say, however, is that this...


...does not work. We know that because quantum objects violate the Bell inequalities. That means that the outcomes of quantum measurements cannot be just a matter of revealing pre-existing properties that were determined in the past of the measurement (in your example, the pre-existing properties would be that you want milk and the shop is out of milk).

In other words, quantum objects do not obey all of your classical intuitions. Does that answer your question?

Not really.I don't know if you understand me to be trying to find some way around the UP(OK term?)

I believe ,within the constraints of my crude understanding that the UP is entirely applicable in all circumstances.

I also assume that it applies whether or not there is any kind of human or sentient person to observe it.

It is ,as I have understood it an integral feature of the physical world (whether or not there is anyone to observe)

I don't know but I suspect that you may think I am implying the opposite .

My "classical" example was just a kind of reverse analogy.It has no significance in what I understand to happen at the quantum level.

That said, @Paul Colby says that the objects do not contain information that determine the outcome of any interaction and ,I must accept that.But does he mean that they don't hold information that entirely determines the outcome of interactions or that they don't hold any information at all?

If they do hold information but it does not exactly determine the outcome of an interaction ,what happens to that information and what effect (if any) does it have on the outcome?

Parading my ignorance further now, if a spin up particle meets a spin down particle is the outcome statistically different to a spin up particle interacting with another spin up particle?(if that makes any sense)

Would that count as a quantum interaction or is it hopelessly naive?

 

[PeterDonis]

I believe ,within the constraints of my crude understanding that the UP is entirely applicable in all circumstances.

Then you are wrong. Sorry to be blunt, but that's just the fact. I gave you an explicit counterexample. I'm not making it up; it's a straightforward application of basic QM that you'll find in any textbook.

I would strongly advise you to take some time to learn basic QM from such a textbook. I personally think Ballentine is a good one. Other people might have others they can suggest. But you really need to improve your "crude understanding" if it's leading you to make such a false claim.

I also assume that it applies whether or not there is any kind of human or sentient person to observe it.

This part is true; applying a quantum operator that models a measurement in no way requires a human or sentient person.

It is ,as I have understood it an integral feature of the physical world (whether or not there is anyone to observe)

This is too vague to even categorize as true or false. Making such vague statements is the sort of thing that taking the time to learn basic QM from a textbook will hopefully cure you of.

My "classical" example was just a kind of reverse analogy.It has no significance in what I understand to happen at the quantum level.

Then, sorry to be blunt again, but it was a waste of your time to post it, and a waste of our time to read it. Why even post it at all if it has nothing to do with the actual subject under discussion?

@Paul Colby says that the objects do not contain information that determine the outcome of any interaction

He's trying to express in your vague language the same thing I said in somewhat more precise language in post #7.

does he mean that they don't hold information that entirely determines the outcome of interactions or that they don't hold any information at all?

Again, this is too vague to even answer. As I've already pointed out, the term "information" doesn't have any single precise meaning. Trying to reason using such vague terms, instead of using the actual math of QM, is another thing that taking the time to learn basic QM from a textbook will hopefully cure you of.

If they do hold information but it does not exactly determine the outcome of an interaction ,what happens to that information and what effect (if any) does it have on the outcome?

Too vague to answer. See above.

Parading my ignorance further now, if a spin up particle meets a spin down particle is the outcome statistically different to a spin up particle interacting with another spin up particle?(if that makes any sense)

It doesn't make any sense.

Would that count as a quantum interaction or is it hopelessly naive?

Hopelessly naive. Please, take the time to learn basic QM from a textbook.

 

[geordief]

Then you are wrong. Sorry to be blunt, but that's just the fact. I gave you an explicit counterexample. I'm not making it up; it's a straightforward application of basic QM that you'll find in any textbook.

Are you referring to entangled particles..
You said "A possible counter example is given by entangled particles"

If that is what you meant I am sure you must be right but did did qualify your statement with "possibly" (although I was surely wrong)

As for the rest of your reply I suggest you take a refresher course in public relations.I am sure you are not normally as rude but I seem to have rubbed you up the wrong way and sadly have not learned much from this encounter. (I am sure you have more pressing affairs to occupy your time)

 

[weirdoguy]

I am sure you are not normally as rude

He is not rude, just straight to the point. We are not talking about opinions here, we are talking about facts. Either what you say makes sense, or not. That's not rude, although if english is not your first language, it may seem like that.

 

[PeterDonis]

Are you referring to entangled particles..
You said "A possible counter example is given by entangled particles"

No, @Paul Colby said that. I didn't qualify my statement about entangled particles at all in post #9--indeed, my point in that post was to explain why his "possible" is really a certainty.

sadly have not learned much from this encounter.

Perhaps not, but you have learned some things: that your claim about the uncertainty principle applying everywhere is wrong, and that terms like "information" and "observer" are too vague to use in trying to reason about what QM says. Those might be unwelcome things for you to learn, but they're true.

I gave you advice for how to learn more. Whether you take it is of course up to you.

 

[geordief]

No, @Paul Colby said that. I didn't qualify my statement about entangled particles at all in post #9--indeed, my point in that post was to explain why his "possible" is really a certainty.


Perhaps not, but you have learned some things: that your claim about the uncertainty principle applying everywhere is wrong, and that terms like "information" and "observer" are too vague to use in trying to reason about what QM says. Those might be unwelcome things for you to learn, but they're true.

I gave you advice for how to learn more. Whether you take it is of course up to you.

You assume too much.I have indeed learned those things and I realized on rereading that the "possibility" qualification was not yours(but did not consider it worth clarifying)

I won't readdress the other points I made..That is for you to satisfy yourself with.

Thread closed from my end.

 

[PeterDonis]

You assume too much.I have indeed learned those things

I didn't assume that you hadn't. Indeed, my post said you had. I'm glad you agree.