What percent of everyday-life electrons are collapsed?

[VECT]

So if particles such as the electrons when "measured" forsake their probabilistic wave form and manifest into a definite particle form, does that mean for all intent and purpose the electrons of every objects we observe are already collapsed?

If that's the case how did the labs get pre-collapse electrons for their test? Can collapsed particles be turned back to their pre-collapsed waveform?

And if every day objects do not have already collapsed electrons, how are we observing stable molecules? Do collapsed electrons vs pre-collapsed electrons have any bearings/differences on chemical/physical structures of macro objects?

 

[EPR]

Quantum theory is not a very good description of the observed reality. There are many interpretations of how the world works but few will make sense wrt to the observed world. So the short answer - it's unknown. It's unknown and debatable whether collapse even takes place as such.

Take a look at the interpretations after you've learned the fundamentals and pick your favourite.

 

[Nugatory]

So if particles such as the electrons when "measured" forsake their probabilistic wave form and manifest into a definite particle form,

That’s not what happens. The particle is always described by a wave function; a measurement changes the wave function but doesn’t make it go away.

“Wave-particle duality”, the idea of electrons switching from waves to particles when measured was abandoned many decades ago when the modern theory of quantum mechanics was developed. Unfortunately it still lives on in the popular press, mostly because it’s easier to explain without math, so you’ll see it a lot.

Giancarlo Ghirardi’s book “Sneaking a look at God’s cards” is a good layman-friendly introduction to the real thing.

 

[VECT]

That’s not what happens. The particle is always described by a wave function; a measurement changes the wave function but doesn’t make it go away.

“Wave-particle duality”, the idea of electrons switching from waves to particles when measured was abandoned many decades ago when the modern theory of quantum mechanics was developed. Unfortunately it still lives on in the popular press, mostly because it’s easier to explain without math, so you’ll see it a lot.

Giancarlo Ghirardi’s book “Sneaking a look at God’s cards” is a good layman-friendly introduction to the real thing.

https://books.google.ca/books?id=PEpfZ3Ul8u8C&printsec=copyright&redir_esc=y#v=onepage&q&f=false

Sorry but that book does not look layman-friendly at all.

Also the point you made seem to be just semantics.

"Something" happens when a measurement is made. The wave function gets changed so that it's 0% in all other places and 100% in one place. If it's not correct to call this collapsing into a particle then call it whatever.

But going back to what I was asking, have the electrons of stuff we observe everyday already under-gone this change? And does this change have any bearings on the macro structure of an object?

Pardon my bluntness here but non-physicists such as myself am just interested in straight answers (if there is one) and we don't know if there isn't.

 

[hutchphd]

"Getting measured" is not an intrinsic property of the electron. It describes a set of interactions that necessarily involve the rest of the world. After measurement the electron is still an electron described by a (probably altered) quantum description (wavefunction if you like) and time evolution . It is not like electronic puberty or a Bar Mitvah.

 

[atyy]

"Something" happens when a measurement is made. The wave function gets changed so that it's 0% in all other places and 100% in one place. If it's not correct to call this collapsing into a particle then call it whatever.

Not all measurements collapse the wave function from 0% in one place to 100% in another place. Only a subset of accurate position measurements do so. The measurements in everyday life are not this sort of accurate measurement. For example, it is not possible to measure position and momentum accurately simultaneously, However, in everyday life we do measure position and momentum simultaneously but inaccurately. These inaccurate measurements lead to a different sort of collapse.

 

[atyy]

If that's the case how did the labs get pre-collapse electrons for their test? Can collapsed particles be turned back to their pre-collapsed waveform?

A lab may deliberately make a certain type of measurement to collapse a system in a certain way. Measurement is a type of preparation procedure.

After a system is collapsed, it evolves by the same rules as it was just before collapse. In the case of a measurement that collapses a particle to a definite position, after the collapse the wave function can evolve by spreading out so that it again has an indefinite position.

 

[atyy]

And if every day objects do not have already collapsed electrons, how are we observing stable molecules? Do collapsed electrons vs pre-collapsed electrons have any bearings/differences on chemical/physical structures of macro objects?

Everyday measurements don't affect the chemical/physical structures of macro objects. Of course this depends on what one meas by everyday, but we do have mathematical models for many everyday measurements that can be carried out in the lab, and that correspond to everyday properties of materials such as conductivity.

 

[VECT]

Okay, that actually explains a lot for me, thank you.

And just a last question out curiosity.

Say that you have a glass of water in front of you, and you have the power to manipulate the waveform/wavefunction of every electron of every atom in that water to the exact degree of what you want, what would that do on a macro scale? Can you theoretically change that glass of water to wine?

 

[DaveC426913]

https://books.google.ca/books?id=PEpfZ3Ul8u8C&printsec=copyright&redir_esc=y#v=onepage&q&f=false

Sorry but that book does not look layman-friendly at all.

Indeed. The only e-version is for Kindle. Nothing for Kobo.

Pity, it would have been emboughtened in two minutes flat.

 

[atyy]

Say that you have a glass of water in front of you, and you have the power to manipulate the waveform/wavefunction of every electron of every atom in that water to the exact degree of what you want, what would that do on a macro scale? Can you theoretically change that glass of water to wine?

No you can't, because wine and water differ in their nuclei of their atoms also, not only the electrons of their atoms. So one would need greater magical powers than this.

 

[VECT]

No you can't, because wine and water differ in their nuclei of their atoms also, not only the electrons of their atoms. So one would need greater magical powers than this.

Right, but isn't nuclei particles also just waveforms governed by the wavefunction :)

Anyhow, appreciate very much the responses.

 

[atyy]

Right, but isn't nuclei particles also just waveforms governed by the wavefunction :)

Roughly yes. In a quantum theory, one specifies
1) the quantum state (in many cases this is also called the wave function)
2) the Hamiltonian (which governs how the state changes with time)
3) the observables (which govern what measurements can be made)

So if you have arbitrary control over all of these, you can make any system you want.

 

[DrChinese]

1. But going back to what I was asking, have the electrons of stuff we observe everyday already under-gone this change? And does this change have any bearings on the macro structure of an object?

2. Pardon my bluntness here but non-physicists such as myself am just interested in straight answers (if there is one) and we don't know if there isn't.

1. A bound electron in an atom normally will not have a definite position or momentum at any time. If you observe it, you might well free it from the atom.

2. There are no "straight answers" to many questions about Quantum Mechanics. The reason is: QM features very accurate (and useful) complex mathematical descriptions that do not translate well into normal language (such as English). Trying to describe the position or momentum of a bound electron is an example. Ditto with trying to explain electron spin (what is spinning?). And most bound electrons can be considered as entangled with other electrons, thereby losing their individual identity and instead acting as part of a quantum system.

So please understand that no one here is trying to evade your questions by giving you a run around.

Also: You asked about turning water into wine. The issue is that there are conservation rules: total quantum numbers (including mass-energy) do not change under any known physical processes. As already mentioned by others, the nuclei of molecules of wine ingredients are different than those of water molecules.

 

[PeterDonis]

isn't nuclei particles also just waveforms governed by the wavefunction

"Waveforms governed by the wave function" is not the same as "you can do whatever you want".

In a quantum theory, one specifies
1) the quantum state (in many cases this is also called the wave function)
2) the Hamiltonian (which governs how the state changes with time)
3) the observables (which govern what measurements can be made)

You left out a very important one: 4) the Hilbert space (which describes the available degrees of freedom). States that are described by "water" might not even share a Hilbert space with states that are described by "wine".

if you have arbitrary control over all of these

Which you never do.

 

[PeterDonis]

"Something" happens when a measurement is made.

Yes: what happens is that the system being "measured" (electron, glass of water, whatever) interacts with another system, called the "measuring device". This correlates properties of the measuring device with properties of the system being measured; the properties of the measuring device are assumed to be things that we can "read off" directly from the measuring device (like where a pointer points on a dial, or what numbers appear on a digital readout) and which then tell us something about the system being measured.

For a more technical description, you could try this Insights article:

https://www.physicsforums.com/insights/the-7-basic-rules-of-quantum-mechanics/

Note that I didn't use the term "collapse" at all in the above. Rule 7 in the above Insights article talks about that; but note that the term "collapse" in the literature on QM very often does not mean Rule 7, but rather indicates the use of some particular interpretation of QM that goes beyond the 7 Basic Rules. So it's often not possible to answer questions about "collapse" independently of a specific interpretation of QM. Discussion of QM interpretations, here at PF, should be done in the subforum of this one on Quantum Interpretations and Foundations.

have the electrons of stuff we observe everyday already under-gone this change?

Unless we take special precautions to isolate a particular quantum system in a lab, everything is always interacting with other things. But these interactions are not a single "change", they are a continuous process that is always going on. Isolating a quantum system in a lab so it only interacts and gets "measured" at a particular time that we control is a very unusual thing.

 

[EPR]

That’s not what happens. The particle is always described by a wave function; a measurement changes the wave function but doesn’t make it go away.

The wave function is a mathematical abstraction from Hilbert space. It's not even there before the measurement so how can it go away or stay in place

 

[EPR]

Right, but isn't nuclei particles also just waveforms governed by the wavefunction :)

Anyhow, appreciate very much the responses.

Waveforms are theoretical. Their "waveness" is inferred by their particle-like properties in experiments..
Since your question is about our daily life experience(and has little to do with qm as it is known), be advised that we(as large macroscopic bodies) are always dealing with the particle aspect of quantum systems. There is no exception to this.
QM serves the purpose of explaining how those particles move and interact as they neither move classically(with trajectories), nor have definite properties at all times.

Your OP question is very interesting, but deeper than can be addressed with the currently known facts. It's thought that decoherence plays a leading role how macroscopic objects stay classical but why they manifest classically and these laws like F=m.a arise and not some others is generally unknown.

 

[StevieTNZ]

https://books.google.ca/books?id=PEpfZ3Ul8u8C&printsec=copyright&redir_esc=y#v=onepage&q&f=false

Sorry but that book does not look layman-friendly at all.

It is actually a very good layman friendly book. That's one of the reasons I purchased a copy and read it in its entirety.

 

[atyy]

You left out a very important one: 4) the Hilbert space (which describes the available degrees of freedom). States that are described by "water" might not even share a Hilbert space with states that are described by "wine"

Informally, we can consider them different excitations of the same quantum fields. In that sense, they share the same Hilbert space.

 

[PeterDonis]

Informally, we can consider them different excitations of the same quantum fields. In that sense, they share the same Hilbert space.

I suppose if you are willing to consider the Hilbert space to be, heuristically, the Fock space of all of the Standard Model fields combined (i.e., one could have anywhere from zero to an unbounded number of "particles" of each type), you could do this. Then the problem would be to show that there is a nonzero transition amplitude between the "water" subspace and the "wine" subspace of this overall Hilbert space.

 

[VECT]

If I see an audio version of that book I'll listen to it, no promises.

Look I'll be honest here, as much as all of physics is interesting to people here, to the general public, it's really just two things:

-Relativity: Black-Hole (FTL, time-travel..etc.)
-Quantum Physics: Interpretation of the Measurement Problem

And as for that second subject..

On one hand you have physicists who goes off on a tangent talking about the profession's glorious past all the way back to Copernicus and Newton and how people like Schrodinger regretted to ever delve too greedily and too deep; and who now is trying to fend off the masses with equations and technicalities because really there's nothing disreputable going on here please don't cut my fundings.

Then on the other hand you have full blown zealots from every denomination of every religion and mysticism that's still around since stone age going "told ya".

I try to get my itching questions answered without posting on forums so the can of worm don't get stirred, but it's pretty hard sometimes.

I'll be sure to post further questions down in the quarantine zone you guys setup if I have them.

 

[atyy]

I suppose if you are willing to consider the Hilbert space to be, heuristically, the Fock space of all of the Standard Model fields combined (i.e., one could have anywhere from zero to an unbounded number of "particles" of each type), you could do this.

Yes, that's what I was thinking. There is the problem that a Fock space is not the appropriate space in a rigorously constructed interacting relativistic quantum field theory, but since the standard model is not there yet, I thought it's ok to give an answer at the non-rigorous level that the interaction picture is still used in most books.

Then the problem would be to show that there is a nonzero transition amplitude between the "water" subspace and the "wine" subspace of this overall Hilbert space.

That's different from what I was thinking of, but it does make sense to ask whether there is a nonzero transition amplitude between the water and wine subspaces. This corresponds to saying, if we make the measurement "Is this wine?" on water, will we receive the answer "yes" with some non-zero probability.

What I was thinking of is that if we have 2 different vectors in the same Hilbert space, then one needs a rotation to change one vector into another. So the question is whether one could devise a time-dependent Hamiltonian that one could apply to make the transition. I imagine that it would be mathematically possible. However, I imagine that it would not be physical (even in principle) as some conservation laws are likely to be broken (but am not sure). In the unlikely case that no conservation laws are broken, I imagine it would be way beyond practical experimental control (like the Schroedinger's cat thought experiment).

 

[DennisN]

Look I'll be honest here, as much as all of physics is interesting to people here, to the general public, it's really just two things:

-Relativity: Black-Hole (FTL, time-travel..etc.)
-Quantum Physics: Interpretation of the Measurement Problem

I'd say various topics in cosmology also seem quite popular with the general public, e.g. Big Bang, expansion of the Universe, size and shape of the Universe, to name a few things (edit: and I can add dark matter and dark energy too; actually there are quite a lot of interesting topics in astrophysics/cosmology ).

And regarding more hypothetical concepts, String Theory and multiverse theories also seem to be quite popular with the general public.

I try to get my itching questions answered without posting on forums so the can of worm don't get stirred, but it's pretty hard sometimes.

For scientific questions and scientific answers, you have come to the right place.

 

[VECT]

I do have another question now considering what people have said.

For everyday molecular bounds, do say the particle probability cloud have to evolve into some kind of 100%-0% state for the molecules to be stable? Or do the proposed varying degree clouds enough to keep everything normal.

And if varying degree particle clouds are enough to keep up everyday appearances, then why does it matter/what difference does it make what form the wavefunction evolve to?

 

[PeroK]

I do have another question now considering what people have said.

For everyday molecular bounds, do say the particle probability cloud have to evolve into some kind of 100%-0% state for the molecules to be stable? Or do the proposed varying degree clouds enough to keep everything normal.

And if varying degree particle clouds are enough to keep up everyday appearances, then why does it matter/what difference does it make what form the wavefunction evolve to?

A molecule is a system of several particles. A hydrogen atom is a proton and an electron; a hydrogen molecule is two hydrogen atoms; and, water is two hydrogen atoms and an oxygen atom. The molecule is typically in its ground state, which is the lowest energy state for that collection of particles, and is stable.

If you take a classical view then you may ask where precisely are the individual particles in this ground state configuration? What QM says is that well-defined positions of these particles are not part of the theory. The theory tells you that the molecule is in the stable ground state, which is not evolving over time.

The relevant wave function is for the entire water molecule: the constituent particles themselves do not have individual wave-functions that are free to evolve. This is another important, non-classical aspect of QM.

From this you can infer the chemical and physical properties of water. There's no need to measure every water molecule to check it is in the ground state.

In any case, in order to explain everyday phenomena you need to build on QM: from chemistry to fluid mechanics etc.

 

[VECT]

The relevant wave function is for the entire water molecule: the constituent particles themselves do not have individual wave-functions that are free to evolve. This is another important, non-classical aspect of QM.

But then if you zoom out again you can say the relevant wave function is for the entire block of water molecules and the constituent molecules themselves do not have individual wave-functions and are free to evolve...etc.

And then if you zoom out enough at certain point stuff just become classic in description and lose their quantum weirdness.

So pretty much nobody really knows right now then.

 

[bhobba]

Quantum theory is not a very good description of the observed reality.

I think what you are trying to say is QM does not conform very well to our classical world intuition. It is an excellent description of observed reality.

Let's processed on that basis; otherwise, the mentors may delete it because it is based on a falsehood.

Thanks
Bill

 

[PeterDonis]

For everyday molecular bounds, do say the particle probability cloud have to evolve into some kind of 100%-0% state for the molecules to be stable?

The molecule is in a "100%-0%" state. It's just not in a "100%-0%" state of position. It's in a "100%-0%" state of energy. There is no single "100%-0%" state; there are different such states for different observables. A "100%-0%" state of position would not be stable; a "100%-0%" state of energy is.

 

[PeroK]

But then if you zoom out again you can say the relevant wave function is for the entire block of water molecules and the constituent molecules themselves do not have individual wave-functions and are free to evolve...etc.

And then if you zoom out enough at certain point stuff just become classic in description and lose their quantum weirdness.

So pretty much nobody really knows right now then.

Quite quickly it becomes computationally impossible to use QM and nothing but QM. You have to build layers of understanding with new concepts at each layer. A good example, perhaps, is biology. You start with QM, build fundamental chemistry on top of that, organic chemistry on top of that, then cell biology, anatomy and animal behaviour etc. It's not a failure of QM that you can't explain animal behaviour purely in terms of QM. QM is the theory of fundamental particles and you need layers of scientific theories that build on it.

Another example is the computer you are using. Ultimately, everything that happens on a computer is binary stuff at a fundamental electronic level (which is also built on QM). But, you can't expect to describe a word processor in terms of computer hardware fundamentals, nor in terms of QM.

The precise way that the classical world emerges is, of course, very hard to model - although I don't think there is too much difficulty is seeing why quantum "weirdness" gets washed out by sheer statistical averages.

 

[bhobba]

The wave function is a mathematical abstraction from Hilbert space. It's not even there before the measurement so how can it go away or stay in place

The meaning of the wave function is interpretation dependant. It can be real or just a mathematical abstraction. One interpretation is based on Gleason's Theorem where it is just an aid to calculating probabilities. Probabilities are also interpretation dependant, but most think they are not 'real' in the sense a physicist would think as real - but again, philosophers argue about that. Hence, one interpretation is it is just a conceptualization, it is not 'real' and can instantaneously change etc. But either way, it is part of the theory and, in principle, can always be assigned some 'value'. Actually, according to decoherence, it is more complicated - but that will take us way off-topic.

Thanks
Bill

 

[EPR]

I think what you are trying to say is QM does not conform very well to our classical world intuition. It is an excellent description of observed reality.

Let's processed on that basis; otherwise, the mentors may shut it down because it is based on a falsehood.

Thanks
Bill

While I agree, you need QT and a set of additional assumptions(a new structure) to explain the classical reality. This was the intent of the quoted passage.

The quantum is very unlike the classical and while I agree that QT explains a wider range of phenomena, it fails to explain the observed classical world in a single, agreeable fashion.

 

[PeterDonis]

while I agree that QT explains a wider range of phenomena, it fails to explain the observed classical world in a single, agreeable fashion

This is a claim about interpretations and is off topic here. Discussions about QM interpretations belong in the interpretations forum. QT makes accurate predictions about the results of experiments, and that is what is on topic in this forum.

 

[VECT]

The molecule is in a "100%-0%" state. It's just not in a "100%-0%" state of position. It's in a "100%-0%" state of energy. There is no single "100%-0%" state; there are different such states for different observables. A "100%-0%" state of position would not be stable; a "100%-0%" state of energy is.

Okay well then now I have to ask:
-How many different observables for particles are there right now?
-Energy, position, spin?..etc.
-Is the Energy observable also subject to some sort of uncertainty principle?
-Given that variation in the Energy observable theoretically disrupt molecular stability, what potential theoretical macro disruptions (if any) can be caused by variations in these other observables?

 

[VECT]

Quite quickly it becomes computationally impossible to use QM and nothing but QM. You have to build layers of understanding with new concepts at each layer. A good example, perhaps, is biology. You start with QM, build fundamental chemistry on top of that, organic chemistry on top of that, then cell biology, anatomy and animal behaviour etc. It's not a failure of QM that you can't explain animal behaviour purely in terms of QM. QM is the theory of fundamental particles and you need layers of scientific theories that build on it.

Another example is the computer you are using. Ultimately, everything that happens on a computer is binary stuff at a fundamental electronic level (which is also built on QM). But, you can't expect to describe a word processor in terms of computer hardware fundamentals, nor in terms of QM.

The precise way that the classical world emerges is, of course, very hard to model - although I don't think there is too much difficulty is seeing why quantum "weirdness" gets washed out by sheer statistical averages.

The spirit of what I was trying to ask is less about a workable model predicating everything from QM variables up to macro variables. At the moment I am just trying to get a picture of what are the potential theoretical macro variations given hypothetical induced variabilities (artificial or otherwise) in QM parameters.

But if all the quantum "weirdness" just gets washed away by sheer statistical averages once stuff gets to the macro scale, then like what I was wondering, what's the point of QM. If things don't actually have the potential to cascade upward into any meaningful impact, all the QM properties people are painstakingly calculating might as well be scribbles on a wall..

edit: other than quantum computer, that thing doesn't need to cascade up all that much, but you get my point