So we cannot know the position of an electron without interacting with it and affecting it. The electron is a cloud of possible positions, with the true location revealed only when we poke it.

Question: Is the electron actually a cloud, which takes a specific location as a result of being poked? Or is it always a point particle with a definite position, albeit that we cannot know without poking it?

My thought is that the wave/particle contradiction can be resolved this way. Sort of like an ocean swell that acts as a wave until it hits a stick, then it is particles acting on the stick.

An unobserved particle does not have definite properties. It exists in a state of possibilities that are not reflective of the state that it is in at the moment, because it does not have a definite state, rather the possibilities are reflective of the state it will be observed to be in.

My hair color doesn't exist to you in exactly the same way.

The electron particles have identified independent engery states or levels within the cloud. So it is not a cloud in the sense of being a disordered mist of particles in some random state.

Poke it? That's called sex.

That is also how it is like the color of my hair

I would like to see a pic of this alleged hair.

It actually exists as a waveform function upon examination. Much like the color of a bag of Skittles.

Let's hope it is not pubic hair.

My public hair is less red-shifted than my pubic hair.

"As with all particles, electrons can act as waves. This is called the wave–particle duality and can be demonstrated using the double-slit experiment.

The wave-like nature of the electron allows it to pass through two parallel slits simultaneously, rather than just one slit as would be the case for a classical particle. In quantum mechanics, the wave-like property of one particle can be described mathematically as a complex-valued function, the wave function, commonly denoted by the Greek letter psi (ψ). When the absolute value of this function is squared, it gives the probability that a particle will be observed near a location—a probability density."

https://en.wikipedia.org/wiki/Electron

https://en.wikipedia.org/wiki/Wave_packet

"In physics, a wave packet (or wave train) is a short "burst" or "envelope" of localized wave action that travels as a unit. A wave packet can be analyzed into, or can be synthesized from, an infinite set of component sinusoidal waves of different wavenumbers, with phases and amplitudes such that they interfere constructively only over a small region of space, and destructively elsewhere.[1] Each component wave function, and hence the wave packet, are solutions of a wave equation. Depending on the wave equation, the wave packet's profile may remain constant (no dispersion, see figure) or it may change (dispersion) while propagating.

Quantum mechanics ascribes a special significance to the wave packet; it is interpreted as a probability amplitude, its norm squared describing the probability density that a particle or particles in a particular state will be measured to have a given position or momentum. The wave equation is in this case the Schrödinger equation. It is possible to deduce the time evolution of a quantum mechanical system, similar to the process of the Hamiltonian formalism in classical mechanics. The dispersive character of solutions of the Schrödinger equation has played an important role in rejecting Schrödinger's original interpretation, and accepting the Born rule.

In the coordinate representation of the wave (such as the Cartesian coordinate system), the position of the physical object's localized probability is specified by the position of the packet solution. Moreover, the narrower the spatial wave packet, and therefore the better localized the position of the wave packet, the larger the spread in the momentum of the wave. This trade-off between spread in position and spread in momentum is a characteristic feature of the Heisenberg uncertainty principle"

https://en.wikipedia.org/wiki/Hydrogen_atom



3D illustration of the eigenstate ψ 4 , 3 , 1 . Electrons in this state are 45% likely to be found within the solid body shown.









These are all bound states eg in Hydrogen and the colors indicate how high the probability density is in these regions (probability density times small volume in that location - chance to find it there)

This is the probability density for example for the ground state of Hydrogen

Your face is a quantum cloud particle

And a thing of beauty.

Depends on which interpretation of quantum mechanics you like the most tbh:
https://en.wikipedia.org/wiki/Interp...ntum_mechanics

I don’t play black jack.

But I did once, and was pissing off the degens at the five dollar table because I wasn’t making correct plays. One piece of filth yelled at me about how the card I was dealt was supposed to be his.

I explained to him that

1. Me making the correct play has occurred in an alternate universe, and there’s no way to know if he’d receive said card.

2. The card I received wasn’t ANY specific card until it flipped face up, it was cycling through all possible remaining cards until it was observed. If it HAD been dealt to him instead it likely would’ve been a different card

He looked at me funny

There is only one universe or megaverse. The only purpose the parallel worlds serve is as the graveyard of wrong theories.

More complicated math is not the way to breakthrough. Instead a brave reframing at the loss of something profoundly valuable is the way to start using some new math servicing at last the true revolution. Ideas first then the hard math that they demand.

The great brains of the past are not betrayed by their brilliance, only by their undeniable love for something whose time has passed.

Nothing is more powerful than an idea whose time has come. The next idea will kill time itself and then bring it to life once more as something we see... for the first "time".

Quantum mechanics is not a strange theory. What is strange is the way we insist in seeing the world betrayed by the veil of large numbers.

What we know are equations. What you talking about is interpretation of those equation both are possible but not testable.

Here is a good analogy of how both particle and probably waves can co-exist.
https://www.youtube.com/watch?v=WIyTZDHuarQ

My understanding of the double slit experiment is that electrons, photons, molecules, only exist once the which path information is known. This knowledge, occurring after a detector is placed over one or both slits, causes the wave function to collapse and we see 2 definite bands of point particle distribution, ie matter exists, as particles. Prior to this information being known, there is only a probability distribution which is a purely mathematical function, a potential, ie. There is no wave that actually exists.

The act of placing a detector over one or both slits was thought to perhaps show that interfering with the set up causes wave like behaviour to morph into particle behaviour. This was debunked by the delayed choice quantum eraser experiments which prove that it is knowledge of the which path info that causes the wave function collapse. The experimental set up firstly allows the which path info to be known (without the use of physical detectors after the slits hence we have not interfered) so we get a typical particle distribution. Then the quantum eraser part of the set up scrambles the which path information. It is now not known which slit the particles went through - we get an interference pattern.

The weird thing is that the experiment uses a bit of kit that splits the photons (or whatever) into entangled pairs. One photon splits off to a detector screen (the signal photon) while it's entangled pair (the idler photon) goes off to be reflected around the experimental set up. If the idler photon follows a path which allows its path information to be known then its entangled pair shows a particle distribution. If the idler photon gets its info scrambled, erased, then its entangled pair shows an interference pattern because the which path info is lost. Due to the added time taken for the idler to whizz round the set up it does not hit its own detector screen until 8 nano seconds after its entangled pair - the cause has occurred 8ns after the effect.

https://en.m.wikipedia.org/wiki/Dela...quantum_eraser

So it seems matter can't exist without knowledge and time isn't an issue for elementary particles

I don't disagree with your description. But I think some people get the impression that something is done on the entangled idler particle side that magically changes the distribution of all the entangled signal particles. Like covering and uncovering the lens of a flashlight shining on the wall. Rather, the setup on the idler particle side separates the idler particles into 3 categories. This allows the identification of 3 subsets of the prior recorded signal particles where interference and non-interference patterns can be identified for those subsets.

This still supports the point of the experiment which you've given a great description of. It's just not as dramatic as some people think.


PairTheBoard

It's called the 'quantum eraser' bec a detector is placed BEHIND one of the slits and, it was thought, that should disallow a particle from 'knowing' that there's a detector and therefor we'd see the interference pattern but it turns out to not work that way. When we gain ANY which-path information the interference pattern disappears (hence 'eraser'). For some this means that there's an observer problem in QM while others offer up some explanation that says there isn't.

Off to youtube you go w/ 'observer problem QM' bec I don't feel like searching one out.

We're talking about the Delayed Choice Quantum Eraser experiment rather than the simpler Quantum Eraser experiment. If you look at the link he gave,

https://en.m.wikipedia.org/wiki/Dela...quantum_eraser

you'll see it explains the difference between the two experiments with diagrams to illustrate.


PairTheBoard

It's a wonder that anyone can understand that stuff esp if we have no free will. Anyway, I meant the delayed choice eraser experiment and I stand by what I meant to say.

https://en.m.wikipedia.org/wiki/Dela...quantum_eraser

From the link. Quantum Eraser Section:
---------------------
They proposed a "quantum eraser" to obtain which-path information without scattering the particles or otherwise introducing uncontrolled phase factors to them. Rather than attempting to observe which photon was entering each slit (thus disturbing them), they proposed to "mark" them with information that, in principle at least, would allow the photons to be distinguished after passing through the slits. Lest there be any misunderstanding, the interference pattern does disappear when the photons are so marked. However, the interference pattern reappears if the which-path information is further manipulated after the marked photons have passed through the double slits to obscure the which-path markings. Since 1982, multiple experiments have demonstrated the validity of the so-called quantum "eraser".
======================

What's in bold is why it's called "Eraser". If the which-path information is later obscured (Erased) the interference pattern reappears. However, it should be noted this erasure takes place for a subset of particles which can be picked out from the totality of particles landing on the "screen" to show the interference pattern for the subset.

However, there's a problem with this experimentally.

From the link:
---------------
Elementary precursors to current quantum-eraser experiments such as the "simple quantum eraser" described above have straightforward classical-wave explanations. Indeed, it could be argued that there is nothing particularly quantum about this experiment.
…
Nevertheless, Jordan has argued on the basis of the correspondence principle, that despite the existence of classical explanations, first-order interference experiments such as the above can be interpreted as true quantum erasers.
=============




So they went to the Delayed Choice Quantum Eraser. They split the photons into entangled pairs called the "Signal" and "Idler". They look at distribution patterns of the Signal photons and of subsets of the Signal Photons where subsets of the Signal Photons are identified by the delayed arrival of entangled Idler pairs. Subsets of the Entangled Idler pairs are identified by grouping them into categories where which-way information is identified and where it has been "Erased". From the perspective of the Entangled Signal Photons the "Erasure" on corresponding Idler Photons is "Delayed". i.e. it takes place AFTER the Signal photon has landed on the "Screen".

The which-way marking of the Idler Photon takes place while its entangled Signal Photon is still in flight. So the Signal Photon "knows" the marking at that time by entanglement. The Signal Photon then lands on the screen. After that, its entangled Idler Photon is randomly mixed with other marked Idler Photons so as to "Erase" their which-way information. The Idler Photon then lands on the detector and by its timing identifies its entangled Signal pair that's already landed. The subset of Signal Photons thus identified shows an interference pattern.

By this Delay of the erasure of which-way information until after the signal photon lands on the screen there is no longer the problem of a possible classical explanation.

See "The experiment of Kim et al. (1999)" from the link.


PairTheBoard

Yeah this set up I think removes earlier ambiguities

[IMG][/IMG]

Signal photons at D0 show a particle distribution overall since all photons are jumbled together, when subsets D3 and D4 are isolated we see particle distribution at D0. When D1 and D2 are isolated we see interference.

[IMG][/IMG]

Note in particular that an interference pattern may only be pulled out for observation after the idlers have been detected (i.e., at D1 or D2).[clarification needed]

So the experiment doesn't confirm retro causality?

It exists as something real, something definite once observed. Until then it's still "real" except not really, just probably, really.

The many worlds interpretation though annoys me. Prove that wrong someone, for the simple fact that I do not like it. Not to say that it isn't true.

See my probably-existing footnotes for clarity of the words true, real and probably below.