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Lunct
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I don't know if I am right, but I have read about how some particles do not even exist until measured. How would we know this?
thank you for clearing that up. But there must me some merit to this interpretation. What is their argument for this? Is this the Copenhagen interpretation? Because I know Niels Bohr believed in the particle disappearance thing.ShayanJ said:We don't. That's part of some [URL="https://www.physicsforums.com/insights/fundamental-difference-interpretations-quantum-mechanics/"]interpretations of quantum mechanics[/URL] which means quantum mechanics itself is silent on it.
Also, even in those interpretations its not like some particles are like this and some are not. Those interpretations consider this to be a property of any quantity related to any quantum system.
btw what interpretation do you believe in? I lean towards the many worlds interpretation.ShayanJ said:We don't. That's part of some [URL="https://www.physicsforums.com/insights/fundamental-difference-interpretations-quantum-mechanics/"]interpretations of quantum mechanics[/URL] which means quantum mechanics itself is silent on it.
Also, even in those interpretations its not like some particles are like this and some are not. Those interpretations consider this to be a property of any quantity related to any quantum system.
This mostly comes from Bell's theorem. It says that nature is either realistic or local, it can't be both. So local theories have to have this property. But of course some interpretations can work around this, like superdeterminism, or maybe many worlds too, I'm not sure.Lunct said:thank you for clearing that up. But there must me some merit to this interpretation. What is their argument for this? Is this the Copenhagen interpretation? Because I know Niels Bohr believed in the particle disappearance thing.
At first, its not a matter of belief, its a matter of preferring one over others. Its an important distinction!Lunct said:btw what interpretation do you believe in? I lean towards the many worlds interpretation.
Is Bohm is kind of like saying that everything follows a deterministic law and there is no free will, along with no measurement problem?ShayanJ said:At first, its not a matter of belief, its a matter of preferring one over others. Its an important distinction!
I'm still not that much specific about which interpretation I prefer, but I do know that I don't like Bohmian mechanics and many worlds.
It's really irrelevant since they all conform to the same math and are equal at the level of "shut up and calculate"Lunct said:btw what interpretation do you believe in?
but the way I see it, it is also important to explain why you can get to that math.phinds said:It's really irrelevant since they all conform to the same math and are equal at the level of "shut up and calculate"
The interpretations happen after the math says what's happening so, yeah, they are an attempt to say WHY the math says what it says but since all interpretations come off the same math, none is preferred (except as a personal preference)Lunct said:but the way I see it, it is also important to explain why you can get to that math.
true *pretends to know what he is talking about*phinds said:The interpretations happen after the math says what's happening so, yeah, they are an attempt to say WHY the math says what it says but since all interpretations come off the same math, none is preferred (except as a personal preference)
But even that is an assumption that is just stated a lot. There may be fringe cases of applications of QM that are still not tested and different interpretations disagree in their predictions about them. It may still be possible to be able to experimentally distinguish different interpretations and we just don't know how or don't have precise enough measurement devices for. One example is quantum non-equilibrium in Bohmian mechanics which I'm not sure in what situation, if any, happens.phinds said:The interpretations happen after the math says what's happening so, yeah, they are an attempt to say WHY the math says what it says but since all interpretations come off the same math, none is preferred (except as a personal preference)
just took the words right out of my mouthShayanJ said:But even that is an assumption that is just stated a lot. There may be fringe cases of applications of QM that are still not tested and different interpretations disagree in their predictions about them. It may still be possible to be able to experimentally distinguish different interpretations and we just don't know how or don't have precise enough measurement devices for. One example is quantum non-equilibrium in Bohmian mechanics which I'm not sure in what situation, if any, happens.
ShayanJ said:It may still be possible to be able to experimentally distinguish different interpretations and we just don't know how or don't have precise enough measurement devices for.
It's just presented this way to pop science audience to make it more interesting.Lunct said:I don't know if I am right, but I have read about how some particles do not even exist until measured. How would we know this?
Paul Colby said:This is only possible if either the theory differs or the way the theory is applied differs in such a way it yields
different experimental outcomes. I know of no case where this is the claim. Has anyone made such a claim?
As I said, one example is the quantum non-equilibrium in Bohmian mechanics.Paul Colby said:This is only possible if either the theory differs or the way the theory is applied differs in such a way it yields
different experimental outcomes. I know of no case where this is the claim. Has anyone made such a claim?
Lunct said:but the way I see it, it is also important to explain why you can get to that math.
Paul Colby said:Look, someone would first need to explain to me what "exists before measurement" even means quantitatively. To get quantitative about it implies some measurement so it would seem that an explanation would be amusing. Exist before measurement isn't even meaningful classically.
Lunct said:but the way I see it, it is also important to explain why you can get to that math.
Lunct said:thank you for clearing that up. But there must me some merit to this interpretation. What is their argument for this? Is this the Copenhagen interpretation? Because I know Niels Bohr believed in the particle disappearance thing.
Lunct said:I don't know if I am right, but I have read about how some particles do not even exist until measured. How would we know this?
Simon Phoenix said:The foolishness of youth. Over 3 decades later and I still don't understand QM - although I don't understand it to a much deeper level now. The greats like Feynman, Weinberg, Gell-Mann, and so on and so on, don't understand it to an even greater depth!
ShayanJ said:As I said, one example is the quantum non-equilibrium in Bohmian mechanics.
romsofia said:So, let's talk about particles overall. From how I understand it, particles are just a utilization of a flat space.
"Quite possibly, in the year 2100 our present quantum field theory, with its apparatus of Fock spaces, Lagrangians, field equations, commutation relations, and S matrices will be seen as a misguided forced marriage of classical field theory with quantum particle mechanics, more naive than the attempts of Kelvin, young Maxwell, and their contemporaries to model the electromagnetic ether with gears and rollers bearings" - Stephen Fulling.bhobba said:I don't know what you mean by that.
If you mean QFT uses SR and not GR - yes that's true.
But what is not so well known is there is a QFT theory of gravity valid up to the Plank scale:
https://arxiv.org/abs/1209.3511
romsofia said:To me, it means the particle concept has to go.
bhobba said:In the usual sense it has gone so I don't see your point.
Thanks
Bill
Paul Colby said:Has this Bohmian formalism been consistently extended to a completely relativistic many particle formalism? Can this be said for an equivalent replacement for LQFT and the standard model? If not it's just more hot air in the quantum swirl. To be a viable replacement for what exists now these things must be shown first. A theory which replaces any of the QM formalism with something with measurable differences must first be consistent with all the physics that is known. This is required before it can be taken seriously.
If by fully one means compatible with GR then nothing is completely. The standard model is Lorentz invariant last I checked though people talk about non-invariant mods. QM is at the roots of so many known and verified things. A replacement/mod of QM has a big bar to meet. Seems prudent to check these known things first. Hence my question, is there a Bohmian replacement for the standard model? Once one starts changing the rules this becomes unclear.atyy said:The standard model is not known to be fully relativistic
This confuses theory with computational approximations IMO but whatever. Unclear what your point is exactly.atyy said:aspects can be notionally replaced by non-relativistically by lattice models
QT is a physical theory, and if you understand its formalism and how to apply it to observations in the real world, you have understood all there is to understand. What philosophers do with it for whatever purpose (I've never understood which purpose, to be honest), is their problem but not one of physics and it cannot be solved within physics. The only incomprehensible thing with QT is thus what philosophers mean with their unprecisely defined words, not QT as a physical theory.bhobba said:One professor said you will spend your whole life trying to understand it beyond its formalism which everybody understands and almost certainly get nowhere. I certainly have tried and failed miserably so basically and frustratingly gave up. Interpretations are valuable for the reason I said - it elucidates the formalism better. And every now and again someone way beyond my class like Bell makes a breakthrough, but they are few and far between.
Thanks
Bill
vanhees71 said:QT is a physical theory, and if you understand its formalism and how to apply it to observations in the real world, you have understood all there is to understand. What philosophers do with it for whatever purpose (I've never understood which purpose, to be honest), is their problem but not one of physics and it cannot be solved within physics. The only incomprehensible thing with QT is thus what philosophers mean with their unprecisely defined words, not QT as a physical theory.
To conclude, the claim that the fundamental principles of quantum theory are today completely understood, so that it only remains to apply these principles to various practical physical problems – is also a myth. Instead, quantum theory is a theory which is not yet completely understood at the most fundamental level and is open to further fundamental research. Through this paper, I have demonstrated this by discussing various fundamental myths in QM for which a true proof does not yet really exist. I have also demonstrated that all these myths are, in one way or another, related to the central myth in QM according to which objective unmeasured reality does not exist. I hope that this review will contribute to a better general conceptual understanding of quantum theory and make readers more cautious and critical before accepting various claims on QM as definite facts.