I disagree with your analysis and do not see it as consistent with QM. — Kenosha Kid
Clearly, wavefunctions represent waves, not particles as you insist from your interpretation. — Metaphysician Undercover
By the way, why do you present this stuff on a philosophy forum when you are completely uninterested in philosophical discussion of it? Why leave your peers? Have you been rejected? — Metaphysician Undercover
For instance: is the electron wavefunction the only quantity that affects where the electron can be found? — Kenosha Kid
I thought the electron couldn't be 'found' anywhere until it is measured? It is not a discrete entity that exists in some unknown location until such time as it is registered. In fact there really is no such thing as 'an electron' until it is measured, when it manifests as a registration on a plate - which is the basis of 'the measurement problem'. — Wayfarer
But your explanation presumes that there is an electron as a discrete existing particle that exists independently of being measured. Whereas, if you are to question the 'Copenhagen Interpretation', isn't that precisely the point at issue? — Wayfarer
It referred only to the general ideas of himself and Bohr with respect to what could and could not be stated on the basis of quantum physics. So I hardly think it's 'simplistic'. — Wayfarer
However, the 'collapse' of the wave function is actually a metaphor, as there never is an actual wave per se (any more than there is an actual particle). — Wayfarer
and as MU observed, this is a philosophy forum, not a physics forum. I do ask questions on that forum also, but they give pretty short shrift to philosophy over there. — Wayfarer
If I'm out of line in my OP, can you be a bit more explicit? — Kenosha Kid
In the double slit experiment, the back screen is treated as ideal. This means the only thing that affects where the electron can be measured is the electron wavefunction, which is ambiguous, hence the measurement problem.
The insight drawn from this is that the wavefunction evolves into this ambiguous state and can collapse to any position on the ideal screen. But this holds only for ideal screens. — Kenosha Kid
The measurement problem is that the wavefunction that describes the electron can be in a superposition of observables, but when we measure it it's always in one. It is always a wave. — Kenosha Kid
With the double-slit experiment, you can considerably vary the rate at which particles are fired without effecting the resulting interference pattern. That is, roughly speaking, 24 hours at 1 particle fired per second would give the same pattern as 86,400 particles fired in 1 second (all else being equal).
I know this is one of the strange things about the experiment, and as I understand it, this is the origin of the idea that the particles fired one-at-a-time 'interfere with themselves', which I think seems a very lame idea (but as I said, I'm not a physicist).
However the point which struck me is that if the inteference pattern is not rate-dependent, then it means that time is not a factor in the generation of the interference pattern i.e. if the same pattern can be generated in 1 second as in 24 hours, then 'time' is not a variable (as 'rate' is a function of 'time'). And that struck me as being at least philosophically significant.
The measurement problem is that the wavefunction that describes the electron can be in a superposition of observables, but when we measure it it's always in one. It is always a wave. Even if we managed to measure its position to arbitrary accuracy, it would be a wave in momentum space still. (Likewise if we measure it's momentum exactly it's a wave in space. This is the uncertainty principle.) — Kenosha Kid
But your explanation presumes that there is an electron as a discrete existing particle that exists independently of being measured. — Wayfarer
Kenosha Kid likes to waffle. — Metaphysician Undercover
I generaly find Kenosha's posts a model of clarity. I often don't agree with them but not because I think they're 'waffle'. — Wayfarer
Not according to the transactional interpretation of quantum mechanics, which holds that the actual trajectories a particle takes are not just determined by the retarded wavefunction going from time t to t', but also the advanced wavefunction going from time t' to t. (Advanced wavefunctions come up in standard QED as well, to yield the electron self-energy). In this interpretation, the complex conjugate is essentially a message from the future. The electron takes the real trajectories it does in part because it has information about where it's going or, from another viewpoint, where it's conjugate came from. — Kenosha Kid
The true boundary conditions of any particle are its birth and death: where and when it was created, and where and when it will be destroyed. These are facts of each particle. This is the full time-dependent wavefunction of the electron which is, relativistically speaking, equivalent to a static 4D wave. — Kenosha Kid
A good basis set that puts wavelike and particle-like extremes on equal footing is the stroboscopic wave-packet representation, on which I wrote my master's thesis. All of the above still holds: we simply replace Pauli exclusion of two electrons being in one kind of state (position) with that of two electrons being in another kind of state (stroboscopic wave-packet). The exclusion principle holds across all such bases (e.g. you cannot have two like-spin electron plane waves with the same momentum, which is what I had in mind for the states k, j', k" and k"', though these could be position, orbital, Bloch, Wannier or stroboscopic states or anything else you might consider, it makes no difference to the argument). — Kenosha Kid
If you want to know more about why individual electrons are waves, you can Google it. — Kenosha Kid
The new-ish bits are that a) one cannot draw conclusions about where a particle may be found at a given time by considering only that particle at the time, and b) that the birth and death of a particle are its true boundary conditions. Those might be considered novel or controversial. — Kenosha Kid
When a particle moves from event (r,t) to (r',t'), it still does so by every possible path (Feynman's sum over histories). If you sum up every possible r' at t' and normalise, you recover the wavefunction at t'. — Kenosha Kid
The OP holds that the complex wavefunction is an ontic description -- or fair approximation to such -- of how particles propagate through space and time as we represent them. — Kenosha Kid
This is evident in the various interpretations of QM. in Copenhagen, the electron is a complex wave, the field acts linearly, there is one measurement outcome and spontaneous collapse. In MWI, the electron is a complex wave, the field acts linearly, there are an infinity of outcomes and the wave evolves forward in time deterministically. In Bohm, the electron is a real, classical particle, the field is nonlinear, there is one outcome, and the particle evolves forward in time deterministically. In transactional QM without my edits, the electron is a complex wave, the field is linear, there is one outcome, the wave evolves forward and backward in time but probabilistically. — Kenosha Kid
The measurement problem is that the wavefunction that describes the electron can be in a superposition of observables, but when we measure it it's always in one. It is always a wave. Even if we managed to measure its position to arbitrary accuracy, it would be a wave in momentum space still. (Likewise if we measure it's momentum exactly it's a wave in space. This is the uncertainty principle.) — Kenosha Kid
Told!
By the way, why do you present this stuff on a philosophy forum when you are completely uninterested in philosophical discussion of it? Why leave your peers? Have you been rejected? — Metaphysician Undercover
As Heisenberg said 'We have to remember that what we observe is not nature herself, but nature exposed to our method of questioning.' — Wayfarer
Disgusting, MU. Whatever happened to you that instead of a reasonable courtesy and the good sense to learn you seem invariably to default to a dogmatic whackdoodleism whose first characteristics are denial of reality and denial of fact in favour of the world as MU thinks it is. What school taught you that? — tim wood
What the fuck do you know about reality? — Metaphysician Undercover
They all acknowledge that there is a deep philosophical problem sorrounding the ontological status of the wave function - whether it's real, or simply a mathematical device, or an artefact of the understanding. None of that is resolved. — Wayfarer
The back screen is physical, it's not 'ideal'. When you run the experiment, the results are recorded on a physical screen. — Wayfarer
It referred only to the general ideas of himself and Bohr with respect to what could and could not be stated on the basis of quantum physics. So I hardly think it's 'simplistic'.
— Wayfarer
In truth, it's less the interpretation and how it's applied — Kenosha Kid
But again, the Schrodinger equation is wave-like, but it is an actual wave? — Wayfarer
But that got smacked down with: don't be stupid, the particle interferes with itself! (per Dirac). — Wayfarer
Kenosha Kid likes to waffle. When it suits Kenosha's purpose, the electron is a particle. When it suits Kenosha's purpose, the electron is a wave. But Kenosha adheres to no concrete principles to distinguish between when the electron is observable as a particle, and when it is observable as a wave. Kenosha Kid will call it a particle, or a wave, depending on what is required at that point in the discussion. — Metaphysician Undercover
Please point out where you think I failed to understand it [the interpretation of the wave function collapse] — Kenosha Kid
The probability of finding [the object] at a given position is unaffected by this phase. This is not a general feature of wavefunctions. — Kenosha Kid
"Somehow"? So if its always a certain state, and only changes its state when interacting with a measuring device, which would also be made of waves, then what is so special about a measuring device (which is just a large group of electrons) that changes the nature of an electron? And how do you know that what you are talking about isn't the measurement, but what is actually measured, if the end result is an effect of electrons interacting with a measuring device which you dont get when the electron isn't measured?The particle-like behaviour evident in measurement is not that the electron ceases to be a wave at all, but that the wave somehow reduces to a single Eigenstate of the measurement operator. — Kenosha Kid
Her you talk about single electrons, as if they are a particle before going through the slits.If the voltage of the cathode is reduced such that only one electron fires out, say, per ten seconds, eventually the same pattern builds up. From this we deduce that each electron is a wave. — Kenosha Kid
This isn't addressed to you per se, just for general clarity: the concrete principle adhered to is the expansion postulate of QM, which states that the wavefunction is always a linear admixture of one or more Eigenstates of a given operator. After measurement, this is equal to a single Eigenstate of the measurement operator.
QM does not maintain two different types of electron: one wave-like, one particle-like, and swap between them. It is always a wave. That wave can be a position Eigenstate or not. I think I've already addressed this once before.
The particle-like behaviour evident in measurement is not that the electron ceases to be a wave at all, but that the wave somehow reduces to a single Eigenstate of the measurement operator. — Kenosha Kid
Not according to the transactional interpretation of quantum mechanics, which holds that the actual trajectories a particle takes are not just determined by the retarded wavefunction going from time t to t', but also the advanced wavefunction going from time t' to t. (Advanced wavefunctions come up in standard QED as well, to yield the electron self-energy). In this interpretation, the complex conjugate is essentially a message from the future. The electron takes the real trajectories it does in part because it has information about where it's going or, from another viewpoint, where it's conjugate came from. — Kenosha Kid
We would make such a demand of the cathode: for an electron to be emitted at point (r,t) there must be an electron at (r,t). It is only sensible that we do so for the hole the electron will occupy. (It's worth convincing yourself that this hole also has a history. For every electron that vacates position r to occupy position r', it leaves behind a hole and goes to where the hole previously was, describing an electron hole that vacates position r' to occupy position r. We do not need to consider it the same hole throughout, but there must be some conservation of hole-ness.) — Kenosha Kid
The true boundary conditions of any particle are its birth and death: where and when it was created, and where and when it will be destroyed. These are facts of each particle. This is the full time-dependent wavefunction of the electron which is, relativistically speaking, equivalent to a static 4D wave. Unlike in the QM of the Copenhagen interpretation, the conjugate solution (from death to birth) is also a solution when these boundary conditions are applied. This solution eliminates almost all of the trajectories possible (and expected) in Copenhagen QM. And this is just the single-particle picture. — Kenosha Kid
As we expand the picture to include more bodies in the universe, especially the rest of the electronic field, more and more remaining trajectories are removed by things like scattering and Pauli's exclusion principle. — Kenosha Kid
If not, we're left with a solution that looks like a hugely constrained version of the many-worlds interpretation. I name this the not-many-worlds interpretation of quantum mechanics. — Kenosha Kid
Furthermore in the case of atoms the claim that these are “particle trajectories” has been re-examined recently by Flack and Hiley [47] who have concluded that the flow lines, as we shall now call them, are not the trajectories of single atoms but an average momentum flow, the measurements being taken over many individual particle events. In fact they have shown that they represent an average of the ensemble of actual individual stochastic Feynman paths.
And this is a philosophy forum, where [E−V]u=12m[p−A]2u is not, as it were, lingua franca. — Wayfarer
Please point out where you think I failed to understand it [the interpretation of the wave function collapse]
— Kenosha Kid
If you posted your OP at physicsforum.com, I'd be interested to see what other physicists say about it. I intuitively feel there's a problem with it, but of course I don't have the skills to say what, exactly. — Wayfarer
So the challenge to you is to explain how you manage to reduce the wave transmission of energy to a trajectory. — Metaphysician Undercover
in relativistic quantum theories, we do not proceed by specifying an initial state, time-evolving it forward, and asking the probability of spontaneously collapsing to a particular final state. Rather, we have to specify the initial and final states first, then ask what the probability is. This is constructed as a Green's function G(r, t; r', t'). — Kenosha Kid
So how would you reconcile these two incompatible descriptions of the electron, one in which it has a momentum as a wave packet, and the other within which it has a position with the capacity to leave that position creating a hole there? — Metaphysician Undercover
In relation to quantum trajectory theory, here's an article (I haven't had time to read completely read it yet) which might interest you, if the link works: https://doi.org/10.3390/e20050353
entropy 2018, 20(5), 353 — Metaphysician Undercover
Interestingly this popped on my radar today, describing something very similar to what the OP describes but with light waves instead of electron waves.
https://scitechdaily.com/scientists-crack-quantum-physics-puzzle/ — Kenosha Kid
The genuinely controversial part of the OP is the idea that, if we could solve the many-body wave equation for the whole apparatus, we would find that a given electron does not have the characteristic double-slit band pattern at a given time. — Kenosha Kid
Is there any 'given electron' - prior to it being measured? — Wayfarer
Yes, in quantum theory, including quantum field theory, the electron is considered to be there whether it's measured or not. — Kenosha Kid
What is meant by ‘position’ in the quantum realm? Nothing more or less, Heisenberg answered, than the result of a specific experiment designed to measure, say, the ‘position of the electron’ in space at a given moment, ‘otherwise this word has no meaning’. For him there simply is no electron with a well-defined position or a well-defined momentum in the absence of an experiment to measure its position or momentum. A measurement of an electron’s position creates an electron-with-a-position, while a measurement of its momentum creates an electron-with-a-momentum. The very idea of an electron with a definite ‘position’ or ‘momentum’ is meaningless prior to an experiment that measures it.
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