Questions about Heisenberg's Uncertainty Principle & Vacuum Energy

[jtbell]

QM makes predictions for the outcomes of experiments that we can actually perform. More precisely, it predicts the probabilities of various outcomes for an experiment. It does this very successfully. However, the mathematical formalism of QM simply does not address the question of what is "really happening" before we make a measurement.

People have invented various descriptions of what is "really happening." We call them interpretations of QM. All currently viable interpretations reduce to the same mathematical formalism for predicting the results of experiments, so they are (so far) unfortuately indistinguishable by experiment.

That doesn't prevent people from arguing vigorously about interpretations. Usually we have a few ongoing threads like this, but there don't seem to be any at the moment. Maybe they all got tired of arguing for the time being.

 

[Sillyboy]

Yes. You've described what happens, but not how it is so.

how?

 

[zonde]

2 plus 2 equals to 4. under what conditions?

Well, physical quantity represented by numbers should be conserved. If it's not then 2+2=4 is not necessarily true for all cases.

now, you are telling me, there's no explanation other than maths. how is that happened? when math became more real (even though its very roots lies in neanderthal brains) than the fact and effect?

The problem might be that while inside mathematical formalism of QM there are quantities that are conserved (there should be some otherwise it's not math) they are not the ones that we can easily tie to physical quantities.

 

[DrChinese]

...now, you are telling me, there's no explanation other than maths. how is that happened? when math became more real (even though its very roots lies in neanderthal brains) than the fact and effect?

what can 94325435435, this number, can express all by itself?

i'm asking you how to shoot a photon towards an electron which can be as big as universe, and you are replying me like a priest. god is everywhere, god is omnipresent, god is electron, it's here, it's there, it's everywhere. and even so, when you shoot a photon at god, you can measure its position. that's what you said... what the hell? how to believe any crazy maths supposed to prove this. my conscience tells me, either you speak without knowing anything or quantum theory is completely a joke.

probably former.

Probably the former.

Meanwhile, your question is one of the big puzzles. Despite dogged analysis by thousands of physicists, no one actually knows why the mathematical formalism works and yet there is no apparent physical model which does too.

So when you shoot a photon towards an electron the size of the universe, you will want to consider the Heisenberg Uncertainty Principle. You will need to consider it when you try to measure its size or momentum. You will need to consider quantum theory when you shoot a quantum particle through a double slit.

On the other hand, you will most definitely NOT need to consider any element of your model when operating at the quantum scale. So I am sorry that seems to disturb you, but the question is does the model work or does it not? It is NOT about whether the model is pleasing philosophically.

 

[DaveC426913]

i'm asking you how to shoot a photon towards an electron which can be as big as universe, and you are replying me like a priest. god is everywhere, god is omnipresent, god is electron, it's here, it's there, it's everywhere. and even so, when you shoot a photon at god, you can measure its position. that's what you said... what the hell? how to believe any crazy maths supposed to prove this. my conscience tells me, either you speak without knowing anything or quantum theory is completely a joke.

Let's keep the hyperbole to a minimum shall we? No need to put words in other peoples' mouths, or to cast aspersions upon their knowledge level.

QM is not intuitive. It will not follow the type of logic you have grown up to think of as common sensical. This is a failing of our common sense, not a failing of the universe's.

The more you learn about it, the more you will be able to embrace it. Do not judge the iceberg on only the tip you can see.

 

[Frame Dragger]

hello, registered just to ask this questions and "if possible" i want philosophical, descriptive, or, "made of words" answers since i don't really know much about physics.

1. Heisenberg and his uncertainty principle; i see a problem there. he says, to see where is the electron, you have to use photons, right? and that gives "unnatural" results, as photon affects electrons (tell me if I'm wrong) BUT, then, if I'm right, we are under constant photon bombardment... so, even if we can measure where this electron is without photons, it will be still unnatural it seems to me... or, there's no natural at all to begin with... so, what do you think about this?

2. vacuum energy. can't we put this in the very beginning instead of little big bang thing better? or, can we say, big bang was "in" vacuum energy? since this vacuum energy thing present even in devoid of matter? and then, can't we say, there was never nothingness, as in, big bang and whatever "surrounds" it? cause, if there are quantum fluctations then i say there's something. simply, putting something in the beginning doesn't help. they still ask you what was there before it, who put it there and stuff like that. i need an omnipresent thing like god too. or maybe i don't, why then?

re: to Bold

I would just add that there is a theoretical "Primordial Vacuum" referred to in BB cosmology; this is not the same Vacuum as described in QM as far as I know. Talking about the "energy" of such a 'thing' is meaningless, vs fields being quantized at every point. It would be as useful to talk about a vacuum vs. a vacuum cleaner.