There are no hidden variables in RQM, and humans do not play any preferred role.
— noAxioms
How do you know there are no hidden variables?
— EugeneW
I didn't say there are no hidden variables — noAxioms

Okay. That's all I asked. Which means they offer an explanation. In BQM, the wavefunction just collapses. As a matter of fact, experiments can be done to discern if they exist or not.

Bohm's efforts seem a desperate attempt to explain quantum mechanics in classical terms as if classical physics is the more fundamental of the two.
The interpretation ( — noAxioms

"Desperate"... Typical. Bohm was called names by his contemporaries. But he was right.

If anyone was desperate, it was Everest. Or Rovelli, for that matter, but he shows some signs of intelligence.

as if classical physics is the more fundamental of the two. — noAxioms

You see hidden variables as classical variables? Don't think so. They are non-local. Classical variables are local, except maybe tidal forces but they can be considered in arbitrary small regions of space. Maybe space itself is made of hidden variables. I don't see what Napoleon or Casar have to do with QM.

You seem to mix bits from RQM, Copenhagen, and Bohmian mechanics — noAxioms

"Seem" indeed, because I don't mix them. I just say there are hidden variables. Unfashionable, exciting lots of irrational underbelly feelings, just as the existence of preons. They are not metaphysical but physical.

Are you referring to traveling analogue waves — universeness

The things that appear on oscilloscopes, old fashioned stuff.

As a maths expert, do you have anything to add that would aid my understanding of the difference between the terms wave /function/form/equation as they are used in maths compared to quantum physics? — universeness

In math a simple wave is a time-dependent vector field defined, say, on the complex plane as
$F\left( z,t \right)$. One can elaborate on this, but I don't think that will help. Fourier series, of course, are associated with waves. But the closest I've come in recent years to producing a wave-like result might be these notes: Wave tunnels to centroids, Compressed wave of infinite length.

Perhaps the most illuminating way to connect the easiest of math waves with QP is to take a look at the foundational equation of the subject, the Schrodinger equation. Recall from basic calculus the mathematical relationship describing the rate of change of something compared with the quantity of that something. This is fundamental to so so much. It says the instantaneous rate of change of a quantity is proportional to the existing quantity at that moment.

$\frac{d}{dt}Q(t)=KQ(t)$. Easily solved to $Q(t)=Q(0)\cdot {{e}^{Kt}}$

Compare this with the Schrodinger equation in simplest form:


$\frac{d}{dt}|\Psi (t)\rangle =-i\left( \frac{{\hat{H}}}{h} \right)|\Psi (t)\rangle$


Notice that the capital K if replaced by $-i\left( \frac{{\hat{H}}}{h} \right)$
gives
${{e}^{Kt}}={{e}^{-i\left( \frac{{\hat{H}}}{h} \right)t}}=Cos(\left( \frac{{\hat{H}}}{h} \right)t)-iSin(\left( \frac{{\hat{H}}}{h} \right)t)$


And this, as t=time progresses, can produce a wave in the complex plane.

My comments are heuristic and descriptive, avoiding complexities beyond my grasp.

If you understand the wavefunction, then you should understand this. If you put cards parallel to the screen (in the double slit experiment) you would see the wavefunction (as on the screen). I don't think the particle travels on all paths at once. It rather jumps from one to the other, within the confines of the wavefunction the wavefunction accompanied the particle — EugeneW

An electron fired ONE AT A TIME from the source, through the slits forms an interference pattern on the screen, unless you put a detector behind the slits. Doing so, will 'collapse the wavefunction' and you will see two lines on the screen instead of the interference pattern. This is the 'measurement problem.' As far as I have read, further efforts have been made to show that it is not some 'affect of the detector' (such as the detection method used by the detector causing the electrons to change their path). So Feynmann suggested that each single electron passes through both slits and effectively 'interferes with itself'. His 'thought experiment' was that the single electron takes all known paths. You say it 'jumps from path to path.' This idea is just as confusing for me. How would 'jumping' allow a single electron to pass through both slits? The logic of 'jumping' would suggest passing through one slit, then stopping, changing direction, moving back, and onto another path and then moving through the second slit. Even as I type this, part of my conscience is telling me that my thinking of QM here is 'too conventional' but my brain fog continues for now on this topic. I get some relief from Feynman's comment of 'Anyone who says they understand quantum mechanics does not understand quantum mechanics. Sorry EugeneW, I appreciate your efforts so enlighten me on this topic but I must be too dense to fully grasp your logic. You seem quite convinced you understand exactly what's going on in the double-slit experiment. I am completely stumped by it for no. I defer to an old song by Toyah Willcox, 'Its a mystery,' (to me)

And this, as t=time progresses, describes a wave in the complex plane. — jgill

I could be wrong, but doesn't $e^{-iHt}$ describe a rotation of a complex vector as time goes on? The magnitude of this vector, is proportional to the probability in standard interpretation, is constant in time. How does that reflect a wavy probability in space? What propagates a probability wave in time? We know the Hamiltonian is the generator of time translations ($e^{-iHt}$ being the translator and H the generating operator associated with a conserved energy). What does it translate? The wavefunction in space. If you multiply the spatial part (also an e power for a free particle) by this translator than the wavy space part propagates in time. If H=0, the space-wavepart is stationary. The zero energy generates no propagation in time. Nevertheless, the particle can have momentum, if the spatial extent is bound.

You say it 'jumps from path to path.' This idea is just as confusing for me. How would 'jumping' allow a single electron to pass through both slits? — universeness

Confusing indeed! Let's say the electron just explores all possible paths to reach for other particles to interact with. It goes through one slit and during this transgress it hops to the other. Then to the other again, passes through, goes to the left to the right, over all possible path parts. The wavefunction accompanying it, determines which path it can move on, so a wavefunction from one slit, or one that's already collapsed after passing through both, will give a different pattern, which builds up from many one particle interactions and reflects the shape of the single particle wavefunction.

How does the particle hop from one path to another? How often does this happen? Well, that's indeed mysterious. It does it fast and instantaneous (seems like c is superseeded, and in a sense it does, I mean, imagine you are that particle; you're here and the next on the other side of the slit, instantaneously, without delay!).

Physics concerns what one expects to measure. Metaphysics concerns what is. — noAxioms

I don't agree with this interpretation. Physics makes predictions of the results of a particular experiment but it then accepts the actual results as what is.
Metaphysics is decribed as:

"the branch of philosophy that deals with the first principles of things, including abstract concepts such as being, knowing, identity, time, and space."

and

"abstract theory with no basis in reality."

I prefer the scientific method employed by physics to the nonetheless interesting philosophical musings of metaphysics.

Hey, whatever floats your boat — noAxioms

Hey, Right back at you!

I don't think human consciousness is an assembly of components. More of a process that takes place, like combustion, involving not necessarily the same matter at any given time, just like a candle flame's atoms are almost completely different than the 'same flame' a minute later. — noAxioms

Hey, whatever floats your boat!

They've been measured, so they exist to us by that definition. They're galaxies, and separate galaxies might merge into bigger ones, but they hardly just cease being there after only several billion years — noAxioms

Well, it might have been more accurate for me to say that the print in my room of that area of space looks nothing like that anymore.

So not all paths are taken at once but parts of paths. Feynman made it confusing himself.

Thank you, I downloaded the two pdf's but the maths is quite advanced (at least for me) so I will attempt to understand it at some point.

imagine you are that particle; you're here and the next on the other side of the slit, instantaneously, without delay!) — EugeneW

Brian Greene talks about this type of 'quantum weirdness' and 'quantum fluctuations.' A particle which is on one side of a barrier simply 'almost spontaneously' appears on the other side and he just says 'we don't know why or how, it just does. So I go back to a previous point I made. Thinking about and discussing QM with others will remain good practice and good fun, if somewhat frustrating, but I think we probably need another million years of science and scientists before we 'know.'

Thinking about and discussing QM with others will remain good practice and good fun, if somewhat frustrating, but I think we probably need another million years of science and scientists before we 'know.' — universeness

Well, hidden variables offer an answer. They are non-local variables. Bohm was ridiculed for it. He was literally called names by his contemporaries (a frustrated Troskyan, having an unmatured brain, etc.). Hidden variables were not done. You can even considering them being space itself surrounding the particle. Virtual particles wavefunctions could make up the bulk of space and curve empty space negatively (these kinds of things are what you're banned for on physics sites...).

What he means with "almost" spontaneously?

So not all paths are taken at once but parts of paths — EugeneW

To me, this almost suggests that the electron has some kind of cognisant intent, almost 'deciding' when to jump and things get difficult and almost 'magical' when it gets to two slits and its only one electron.
I may be being a little anthropic here but your suggested behavior of these electrons sounds as if they have panpsychist aspects to them. Maybe some unknown or misunderstood conditions of the double-slit experiment causes an approaching electron to 'smear out' or 'stretch its expanse' so that it passes through both slits and under other conditions it only passes through one of them. Has the experiment been done, whereby the distance between the slits has been incrementally increased and the experiment repeated?

https://www.nist.gov/customcf/get_pdf.cfm?pub_id=919863

I assume he meant 'almost no passage of time,' so I assumed he was suggesting that in some cases the appearance on the other side may happen faster that c but I am just guessing. He said it during a discussion he was having with a large panel of cosmologists which included, krauss, carroll, guth and about 6 others. I watched it on youtube a few years ago but I cant remember its title.

Bohm was ridiculed for it. — EugeneW

Yeah, its hard to judge someone like Bohm but he suffered badly from depression and he was friends with some mystic called Jiddu something.

I think the nature of reality will always remain a mystic mystery somehow. Maybe the basics of nature are geometric structures made of hidden variables reaching out for other structures, and when near their coupling to the vìrtual field offers a means to interact, collapse and get identity. What particle likes to get lost in space...?

Yeah, its hard to judge someone like Bohm but he suffered badly from depression and he was friends with some mystic called Jiddu something. — universeness

But why call hidden variables immature or related to being Trotskyan? Just look in this video... Its written in it.



No wonder he got depressed...

Bohm was mocked "a hopeless fool", "aTrotskyte", a "communist conspiricist", "a traitor"... How can one not sympathize with his ideas?

Seems he is the modern Galilei. In a modern church.

The mathematician complaining about the hostile attitude towards hidden variables was John Nash,

As a matter of fact, experiments can be done to discern if [hidden variables] exist or not. — EugeneW

This is false. One would need to assume certain unprovable postulates (*cough* biases *cough*) to demonstrate this.

You see hidden variables as classical variables? — EugeneW

I don't. I see an interpretation that attempts to get as close as possible to classical intuitions at whatever cost in additional complexity. I prefer the simpler ones (Occam's razor and all), but I am not so naive as to assert any particular interpretation as 'the truth'.

Confusing indeed! Let's say the electron just explores all possible paths to reach for other particles to interact with. It goes through one slit and during this transgress it hops to the other. — EugeneW

You say this stuff like it is fact, when it is only your personal opinion, which is misleading when replying to one who is trying to learn. Last I checked, Bohm does not suggest that the electron goes through one slit and then hops to the other. It takes one path in that interpretation.
The interpretation suggests that the electron detours to the side a bit to migrate to the next positive interference concentration, but it never doubles back and 'takes both paths'. From wiki:

"Trajectories of particles under De Broglie–Bohm theory in the double-slit experiment."

Note that the picture is not entitled: "Trajectories of particles under Quantum Mechanics theory in the double-slit experiment."
Note also that none of the paths double back and pass through more than one slit.

Bohm was mocked — EugeneW

But has anybody proven him wrong? The pilot wave tank thing died a horrible death, but the interpretation lives on.

So Feynmann suggested that each single electron passes through both slits and effectively 'interferes with itself'. — universeness

That's like saying the cat is both dead and alive. It isn't. The electron is said to be in superposition of going through each slit, and the cat is in superposition of being dead and alive. Even then, the latter is wrong since superposition requires a coherent state: the electron states in superposition can interfere with each other and produce a measurable interference pattern. The live cat cannot measurably interfere with the dead cat, and so it not a true superposition.

They done the double-slit thing with buckyballs, which is a huge molecule which they've nevertheless managed to get to interfere with itself.

Physics makes predictions of the results of a particular experiment but it then accepts the actual results as what is. — universeness

If I am looking for my coffee, and see it sitting on the counter, that's a measurement. That I infer that the cup is actually over there is a metaphysical conclusion, but one that works very well for me, so it's second nature in everyday life. Physics says that if I actually go there and reach for the cup, I'd expect it to be measured by my hand when I do that, but physics actually says that that expectation can be made regardless of the metaphysical overhead.

It's a thin distinction, but an important one to me. I named myself 'noAxioms' precisely because there's nothing I refuse to question. I've a long list of things that pretty much everybody believes (including myself) which are nevertheless lacking in hard evidence. The result is a conflict: I believe some things that I know to be likely false, as if there are multiple entities in me with conflicting ideas, and only one of them can be in charge.

They're galaxies, and separate galaxies might merge into bigger ones, but they hardly just cease being there after only several billion years
— noAxioms
Well, it might have been more accurate for me to say that the print in my room of that area of space looks nothing like that anymore.

What something looks like is what you see if you look at it. Galaxies are huge and take ages to change. I assure you it that it still looks like that now from here. Sure, you move a few billion light years in some direction and point the telescope the same way, the view will look different. The picture is definitely dependent on point of view and looks different from significantly elsewhere.

This is false. One would need to assume certain unprovable postulates (*cough* biases *cough*) to demonstrate this — noAxioms

One would need very precise measurements of arrival times. At the moment these measurements are extremely difficult to realize but it could be done in principle. Hidden variables give almost exactly the same predictions as the standard. But not totally.

Bohm does not suggest that the electron goes through one slit and then hops to the other. It takes one path in that interpretation. — noAxioms

It's not Bohm who says a particle hops from one path to another. It's me. An electron travels on parts of all possible paths, directed by non-local variables. This actually happens.

Bohm was mocked
— EugeneW
But has anybody proven him wrong? — noAxioms

Nobody did, as a matter of fact. Just irrational prejudices about QM made Pauli and most others condemn him. Everything was fetched to defend the standard view. Sleazy methods included (he was friends with a mystic... can't be any good coming from them!).

https://www.nist.gov/customcf/get_pdf.cfm?pub_id=919863 — EugeneW

Thanks! I downloaded the pdf and I will read and study its contents and see if it improves my understanding of what's happening in the double split experiment.

Bohm was mocked "a hopeless fool", "aTrotskyte", a "communist conspiricist", "a traitor"... How can one not sympathize with his ideas?

Seems he is the modern Galilei. In a modern church — EugeneW

Yeah, but why did he turn to characters like Jiddu Krishnamurti?

Yeah, but why did he turn to characters like Jiddu Krishnamurti — universeness

Don't ask me but he was, like Bohm a holist (Bohm's holographic universe):

"His interests included psychological revolution, the nature of mind, meditation, holistic inquiry, human relationships, and bringing about radical change in society. He stressed the need for a revolution in the psyche of every human being and emphasised that such revolution cannot be brought about by any external authority, be it religious, political, or social."

Maybe they were lovers, who knows? JK was no quantum theorist, I think. I think they strengthened each other's view. On physical nature as well as soul.

It's a thin distinction, but an important one to me. I named myself 'noAxioms' precisely because there's nothing I refuse to question. I've a long list of things that pretty much everybody believes (including myself) which are nevertheless lacking in hard evidence. The result is a conflict: I believe some things that I know to be likely false, as if there are multiple entities in me with conflicting ideas, and only one of them can be in charge — noAxioms

I particularly like 'there's nothing I refuse to question.' I think Scientific rigor benefits from such an approach and such an attitude.

"as if there are multiple entities in me with conflicting ideas, and only one of them can be in charge"

I think we have three. The RComplex(me), The Limbic system(myself), and the Cerebral Cortex (I).
Combined, they are all my thoughts, my consciousness. That's of course only the result of my internal study of what I am. In a similar way to us trying to figure out what the Universe is from inside it.