Uncertainty

[Ernest Wilson]

Why is "Uncertainty" a Principle. Before you grab the keyboard and tell me "How can anyone be so stupid as not to know about the "Uncertainty Principle"; THERE I have said it for you!! so put your thinking cap on and look into it.
Ernie.

[xelasnave]

It is something so obvious it needs to be set out as a reminder of the reality of the quantum world and to remember solutions should contain the reallity that probability is the rule.
alex

[renormalised (Carl)]

Originally Posted by Ernest Wilson

Why is "Uncertainty" a Principle. Before you grab the keyboard and tell me "How can anyone be so stupid as not to know about the "Uncertainty Principle"; THERE I have said it for you!! so put your thinking cap on and look into it.
Ernie.

Uncertainty is a principle because it's one of the basic tenets which underlies QM (Quantum Mechanics). It governs the behaviour of matter on the scales that QM deals with. An example, with electrons....it deals with the uncertainty in the determination of both the position an electron has at any given moment in its orbit of the nucleus, and the direction (momentum) in which it's moving. If you try to accurately determine one of those values you find that you cannot know what the other is, for any certainty. So, you may know the electron is in position X, but you cannot know exactly where it is moving to. In actual fact, it could be moving in every direction simultaneously. Conversely, if you know it's moving in direction Y, the electron could be in all positions of its orbit simultaneously.

It's all because of a little thing known as quantum superposition or the superposition of state. What this means is until a quantum system is observed, the whole system is in a state of flux such that all the possible paths or events which can occur within that system are equally liable to be occurring all at the same time. In other words, there's an infinite number of probable states that the system can be in simultaneously and it's only when that system is observed that the system collapses into the state that the observer observes it in. Collapses meaning that the most probable state the system can be in, is the one the observer sees or chooses to see that system in. All those other states will either disappear (the Copenhagen Interpretation) or exists as parallel realities (Many Worlds Interpretation or Relative State Formulation) which exist as probabilities of decreasing value the further away from the ground (or collapsed) state they are. Another thing to remember is that the observer can be anything either within or outside that system, be it someone looking at it or a particle within that system interacting with anything within the system. For a system to be in quantum superposition there must be absolutely no interaction with or within it, the moment there is it becomes what the observation tells it to be or sees it as.

I hope that has cleared things up

[ZeroID (Brent)]

I'm certain I've got a headache after all that, .... probably...

[renormalised (Carl)]

Originally Posted by ZeroID

I'm certain I've got a headache after all that, .... probably...

That was the simple explanation

[mikesim (Mike)]

I thought it also had something to do with the following. The photon of light used to make the observation of the particle interacts with the observed particle influencing its observed position?? If the particle wasnt being observed, there would be no interaction with the photon, and so its position and spin would be different?? Or maybe thats an explanation for the masses.

[renormalised (Carl)]

It doesn't have to be a photon with which you make the observation. Just thinking about what to make of the observation will cause the electron (or subatomic particle) to behave accordingly. The observer and the observed can be thought of as the one system. The observer and the observed influence one another...it's like they change positions/rolls.

If the observer didn't make the observation of the particle, then that particle would exhibit the characteristics of all its possible states, including the one in which it found itself in after being observed. So would the photon that was going to be used to make the observation...and so would the observer, from the perspective of the particle and photon. In a very real sense, the observer would not exist at all for the observed particle, because of the effects of quantum superposition. And vice versa...the particle would only come into existence when it was observed. So, in a very real sense, the observer and the observed create one another. The act of observation is an act of creation.

[bojan]

Originally Posted by renormalised

... The act of observation is an act of creation...

... of one bit (or more) of information.

[avandonk]

Always be careful of any 'science' on utube as it is generally quacks that want your money. But as an old fart physicist can I recommend this BBC series.

Here is episode one. Reality - science - nothingness

http://www.youtube.com/watch?v=FdPqi...eature=related

There is more.

If this does not scare your complacency then nothing will.

Bert

[avandonk]

This is also very worthwhile viewing

http://www.youtube.com/watch?v=x0hAL...eature=related


It really shows that real genius is a fleeting phenomena that can border on loss of 'reality'. The irony here is that the search for reality can ruin the apparent one.

Woody Allen said that Infinity is really big especially near the end!




Bert

[CraigS]

Originally Posted by renormalised

In a very real sense, the observer would not exist at all for the observed particle, because of the effects of quantum superposition. And vice versa...the particle would only come into existence when it was observed. So, in a very real sense, the observer and the observed create one another. The act of observation is an act of creation.

Originally Posted by bojan

... of one bit (or more) of information.

I don't believe the speculation that information is created through observation is consistent with the quantum view.
Like energy, information is neither created nor destroyed in QM physics.

Carl's idea I think, is meta-physcial.

Cheers

[renormalised (Carl)]

Originally Posted by CraigS

I don't believe the speculation that information is created through observation is consistent with the quantum view.
Like energy, information is neither created nor destroyed in QM physics.

Carl's idea I think, is meta-physical.

Cheers

You misinterpret what I've written....the information is always there, just not in a form you or I can interpret, when the system is in quantum superposition. The act of creation I am referring to is the collapse of the system into the dominant (most likely) state when the observation of that system is made.

It's like building a castle out of Lego blocks...in all the possible realities in which you and the blocks exist, you have an infinite number of choices as to what to build out of those blocks. They all have an equal probability of existence, so long as a choice isn't made as to what to build. What's more, they have always existed, but have not been realised through making the observation of the system (creating the castle). The act of choosing is the observation of the system and the act of creation. You chose to build a castle.

In a very real sense, there is no distinction between the quantum world and macroscopic reality....they're one and the same.

[CraigS]

Ok .. that's cool.

We should be careful using the term 'creation' … 'reassembled in a new form' is closer to the mark.
I think bojan interpreted Carl's words in the same sense as me …

We get twitchy using the term 'creation'.

Cheers

[renormalised (Carl)]

Originally Posted by CraigS

Ok .. that's cool.

We should be careful using the term 'creation' … 'reassembled in a new form' is closer to the mark.
I think bojan interpreted Carl's words in the same sense as me …

We get twitchy using the term 'creation'.

Cheers

Creation is nothing more than a word. It's what your culture has led you to believe it means is the problem. If we keep having to tippy toe around fools sensibilities just because we don't want to upset their little apple cart, then we'll end up destroying the English language and our society in the process. Let them have their delusions and we will continue on as per normal.

[avandonk]

Creation is only a word that simple folks use. I prefer an infinite unknown. I will not lose my mind as some of my antecedents have. I have no conflict with irrational religious beliefs as I find them both simplistic and total drivel.

The impoderable is when a majority of humanity in our western society really complain when the things that they do not how how they are made or work start complaining how us scientists have got it all wrong!

They can be led by absolute fools who label themselves as Lords.

Let us hope this photon pharks off!

Bert

[renormalised (Carl)]

Originally Posted by avandonk

Creation is only a word that simple folks use. I prefer an infinite unknown. I will not lose my mind as some of my antecedents have. I have no conflict with irrational religious beliefs as I find them both simplistic and total drivel.

The impoderable is when a majority of humanity in our western society really complain when the things that they do not how how they are made or work start complaining how us scientists have got it all wrong!

They can be led by absolute fools who label themselves as Lords.

Let us hope this photon pharks off!

Bert

It's like someone who's illiterate and has a car engine manual telling a mechanic how to do his work and then berates him for getting it wrong!!!

[Ernest Wilson]

I found AVANDONK'S reference http://www.youtube.com/watch?v=FdPqi...eature=related helpful in explaining the history of particle physics a most interestiong documentary, and I will be looking at it a few more times. It may be that the explanation of Quantum Mechanics might have been superseded and that "Uncertainty " is not a Principle. However, a lucid explanation seems still to be wanting. From the little I know, mathematics provides the key to predicting the results of "Wave"- "Particle" experiments. It is the interpretation of those results that invokes "Uncertainty", not the result of the experiments.

I'm hoping that "this Photon pharks OFF" does not refer to me??!, but I'll do it anyway.

Thanks to All, Ernie.

[KenGee (Kenith Gee)]

Once again Ernest dismisses a whole field of science with a wave of his hand, and no explanation. Could it be Ernest thinks he is better then Popper? For those playing at home it's called the Uncertainty Principle for two reasons. It is considered a observation rather then a theory, and it's a principle rather then a law because "laws" are so 17th century.

[renormalised (Carl)]

Originally Posted by Ernest Wilson

I found AVANDONK'S reference http://www.youtube.com/watch?v=FdPqi...eature=related helpful in explaining the history of particle physics a most interesting documentary, and I will be looking at it a few more times. It may be that the explanation of Quantum Mechanics might have been superseded and that "Uncertainty " is not a Principle. However, a lucid explanation seems still to be wanting. From the little I know, mathematics provides the key to predicting the results of "Wave"- "Particle" experiments. It is the interpretation of those results that invokes "Uncertainty", not the result of the experiments.

I'm hoping that "this Photon pharks OFF" does not refer to me??!, but I'll do it anyway.

Thanks to All, Ernie.

I would suggest to you to forget about trying to figure out something you clearly don't have the capacity to understand. Several of us have tried to explain to you in simple terms what is meant by the Uncertainty Principle, why and how it's applied and a simple explanation of the underlying physics. It would be pointless of us to try and go any further if it appears, as it seems, that you still don't get it.

That documentary, which I have seen before, in no way invalidates anything about QM, least of all uncertainty.

If you have trouble with the nuts an bolts of it all, don't mess with the metaphysics of QM...you'll get totally lost and even more confused.

[Zaps]

The Internet is loaded with useful references clearly explaining these things. Wikipedia is always a good start.

Almost every explanation posted online nowadays does nothing more than paraphrase such sources, so cut out the middle-kiddies and go straight for the originals.