A little clarification on quantum theory

[steevey]

No-one has done any experiment like that!

 

And I did place a caveat "domain of validity ". Non-relativistic quantum theory, which is what I think the OP is really talking about would not be expected to hold in such extreme relativistic situations.

 

Near a black hole one would have to use semi-classical gravity, that is the relativistic theory on a classical background.

 

In the more extreme one would expect quantum gravity to kick in, and we have no concrete model for that.

 

 

How would the observer on Earth know that you have detected that the particles are disentangled? It will take time for you to send a message back to him. And if you were right on the horizon this time delay would be infinite! I mean, I am not sure how you would decide what the "same time" means.

 

I will have to think a little more on this.

 

Well if you look at the experiments, when either of any pair of entangled particles is measured, the system disentangles instantaneously, which more or less means infinite speed, so would time dilation even matter if its infinite speed? I mean, infinite speed would match infinite delay.

[Schrödinger's hat]

"System" is far from ambiguous, isn't it? If the math equation version of your statement expresses the same thing, I wonder if it lends itself as easily to questioning what exactly is meant by "system." In my experience, using math instead of descriptive language makes it more difficult to elaborate using concrete examples. If you say that the total momentum of a system never changes, I can come up with numerous examples of "systems" and contemplate what "total momentum" would refer to and whether all the possible momentum-transfers and transformations would always add up to the same amount. OR I could just think in terms of conservation of energy and ask where additional energy would come from or go to if the system was closed.

That statement wasn't intended to be universal. We could elaborate to closed, isolated system, but then the mathematical formulation would have to be expanded too. Mathematics is just a way of representing certain classes of things and the rules for their interaction. Often we need to classify and define these objects. English is exceedingly useful here.

I'm not saying we should not use English statements, just that we should use all of the tools at our disposal.

 

 

Edit: Also, I used n for my summation and i for my index. Shows how much attention I'm paying.

 

Again, where's the unambiguity? In what sense is it a "fundamental quantity?" What does that mean exactly? What does "some angular momentum" refer to? Interacting with charge is clearer language, but also vague. How does it interact with charge? In what sense does it interact? Purely in the sense that two variables "interact" by influencing each other's outcomes by some unknown mechanism?

To be decrease the ambiguity to your standards, without any context or set of definitions I'd have to write a book. You are also just reinforcing my point. The stories are hard to tell in an objective way. I tried to tell you my story without mathematics and you don't get it. This is because my story is hard to communicate, mathematics is not for those who understand it.

Science has an agreed upon set of definitions for most of these terms. The definitions include description and mathematics, throwing away one of our tools for no good reason is silly.

You could argue that physicists are throwing away tools by using mathematics, but it's simply that they could see how to apply one tool and not the other.

If I want to undo a nut and I have a spanner and a screwdriver, I use the spanner. There might be a more efficient way to do it with the screwdriver, I don't know, I can try the screwdriver but it would take a long time and would be awkward and full of problems. I only know how to use the spanner efficiently for this task, it's not like I have any hatred or bias against screwdriver users.

My understanding of a wave function is that it operates as a wave though it consists of numerous repellant fields (electrons) that "dance around" variously disappearing and appearing with a certain probability within the wave. What I don't understand is does a hydrogen molecule, for example, only have two such "dancing points/fields" and do those two move around the nucleus randomly according to the probability-gradiations of the wave-pattern? Have I completely misinterpreted what wave-function refers to?

Yes, you have, you're thinking of it as a collection of particles (or something else I don't understand), this is inadequate. The word move doesn't apply here, dancing is misleading too. Suggesting points and fields are the same type of thing is also wrong.

My story is that the electron is occupying the whole wavefunction all the time, only just after, or during interactions is it restricted to a subset of this space, there are other stories that fit the maths. It is a subtle and difficult concept, in my experience the best way to get an intuitive understanding of things that act in this way is to play with them, or accurate models of them. The models require maths to be accurate, this is why we study maths before trying to understand a wavefunction.

 

In bowling, momentum, mass, and position are experienced intuitively whether they are abstract in some philosophical context or not.

I know plenty of people who have a shockingly inadequate and inaccurate intuitive understanding of momentum. In many cases they can make predictions, but when situations that are not common for them come up they are confused or mystified. This is even more common with magnetism (many people have no intuition). Through examples, playing with toys, making predictions and looking at the outcomes we can slowly build an intuition of these things. We cannot build an intuition of magnetism solely from concepts outside EM, it requires new ones. Spin is no different, it is hard to interact with so a lot of our tools for building intuition are gone.

 

Well if you look at the experiments, when either of any pair of entangled particles is measured, the system disentangles instantaneously, which more or less means infinite speed, so would time dilation even matter if its infinite speed? I mean, infinite speed would match infinite delay.

This is an oversimplification of the situation, there is something wrong with thinking of the wavefunction collapse as an effect. I do not understand fully, I am not sure if anyone understands measurement. This is a case where we have some maths and no story to go with it.

Edited March 2, 2011 by Schrödinger's hat

[steevey]

This is an oversimplification of the situation, there is something wrong with thinking of the wavefunction collapse as an effect. I do not understand fully, I am not sure if anyone understands measurement. This is a case where we have some maths and no story to go with it.

 

But real experiments have been done where entangled particles have been separated by over 100 kilometers, yet they still disentangle instantaneously. What's mathematically happening is that when the particles are entangled, they act as the same particle in a way that the properties of some are Dependant on the other. Both particles have undetermined states such as spin which respond to each other instantaneously as well, i.e. if one goes to spin up, the other goes to spin down. However, when one particle was measured, both the particles stopped acting as the same particle and started acting as their own separate particle again instantaneously. It's not an effect, its the event in which two or more particles which were once entangled become disentangled.

Edited March 2, 2011 by steevey

[Schrödinger's hat]

But real experiments have been done where entangled particles have been separated by over 100 kilometers, yet they still disentangle instantaneously. What's mathematically happening is that when the particles are entangled, they act as the same particle in a way that the properties of some are Dependant on the other. Both particles have undetermined states such as spin which respond to each other instantaneously as well, i.e. if one goes to spin up, the other goes to spin down. However, when one particle was measured, both the particles stopped acting as the same particle and started acting as their own separate particle again instantaneously. It's not an effect, its the event in which two or more particles which were once entangled become disentangled.

 

This is much better, but there is still something misleading in the way I am interpreting what you say.

I am by no means an expert on this subject, but thinking of the results of the two measurements as causally related oversimplifies the situation.

A key point is that information cannot be transmitted by this effect.

On top of that, the concept of 'when the one particle is measured' is not quite valid. In a relativistic world there is only:

An event (or here and now)

Future

Past

Other

The present isn't a valid concept.

 

My understanding of this is limited, perhaps someone more knowledgeable knows what I'm trying to say?

[lemur]

If I want to undo a nut and I have a spanner and a screwdriver, I use the spanner. There might be a more efficient way to do it with the screwdriver, I don't know, I can try the screwdriver but it would take a long time and would be awkward and full of problems. I only know how to use the spanner efficiently for this task, it's not like I have any hatred or bias against screwdriver users.

The point is that you should be able to know how both tools work and what the mechanics of getting a nut loose is in comparison with a screw. It's as hard to talk with math-fixated scientists about methodology as it is to talk to a mechanic about how tools, parts, etc. work when all the person can say is that you just learn from experience. It is possible to analyze the functioning of any system, physical or analytical if you are aware of how it works to do what it does.

 

Yes, you have, you're thinking of it as a collection of particles (or something else I don't understand), this is inadequate. The word move doesn't apply here, dancing is misleading too. Suggesting points and fields are the same type of thing is also wrong.

My story is that the electron is occupying the whole wavefunction all the time, only just after, or during interactions is it restricted to a subset of this space, there are other stories that fit the maths. It is a subtle and difficult concept, in my experience the best way to get an intuitive understanding of things that act in this way is to play with them, or accurate models of them. The models require maths to be accurate, this is why we study maths before trying to understand a wavefunction.

I play with them by critically reasoning from what I read and ask questions about my extrapolations. When I'm wrong, I try to understand why. What you're saying about "the electron" "occupying the whole wavefunction all the time," does that mean that each electron in an atom or molecule has its own wave? Or do multiple electrons combine in the same wave? I used the phrase "dancing around" because if an electron jumps around without continuous motion and appears randomly with a high probability of appearing more in one area than another, this seems like "dancing" or "sparkling" to me. What's more, I don't understand how long the thing actually appears for before it disappears and "tunnels" again, and whether it move continuously in a classical mechanical sense in between "tunneling maneuvres." If not, then it would seem to escape any possible form of force-transfer with other electrons, but that can't be possible for in the case of colliding-atoms, there has to be force-transfer through the electrons.

 

I know plenty of people who have a shockingly inadequate and inaccurate intuitive understanding of momentum. In many cases they can make predictions, but when situations that are not common for them come up they are confused or mystified. This is even more common with magnetism (many people have no intuition). Through examples, playing with toys, making predictions and looking at the outcomes we can slowly build an intuition of these things. We cannot build an intuition of magnetism solely from concepts outside EM, it requires new ones. Spin is no different, it is hard to interact with so a lot of our tools for building intuition are gone.

Spin made sense to me at first, insofar as a moving electric charge generates a corresponding magnetic field. So the idea that the atomic electrons are moving and therefore generate a magnetic field is consistent with the empirical observation of a magnetic field generated by a current moving through a conductor. However, once Swanson started saying that this is too classically mechanical to make sense for a quantum physics concept like spin, it seemed like I must have misunderstood.

 

 

 

[Schrödinger's hat]

The point is that you should be able to know how both tools work and what the mechanics of getting a nut loose is in comparison with a screw. It's as hard to talk with math-fixated scientists about methodology as it is to talk to a mechanic about how tools, parts, etc. work when all the person can say is that you just learn from experience. It is possible to analyze the functioning of any system, physical or analytical if you are aware of how it works to do what it does.

Agreed. It's hard to explain how these things may be learned in a way completely unlike the way I learned them.

 

I play with them by critically reasoning from what I read and ask questions about my extrapolations. When I'm wrong, I try to understand why.

I think we're getting a bit closer to understanding each other here. This is exactly what we do with the mathematics.

The symbols, the numbers, the rules of algebra, they're all just tools for critical reasoning and extrapolation. You could think about the same concepts without them, but from the point of view of someone who is used to thinking with mathematics this seems cumbersome and silly.

 

What you're saying about "the electron" "occupying the whole wavefunction all the time," does that mean that each electron in an atom or molecule has its own wave?

In linear models it's equally valid to think of each particle as having its own wave function, or the collection having a wave function (again, multiple stories work sometimes, don't get fixated on one ontology if you try to think about these things or you'll go mad).

 

I'm still learning and I haven't done much with multiparticle wave functions yet, but here goes. Electrons don't always (often?) work in this way as there are interaction terms. Instead you have one big wave function for all the electrons. In this case they all occupy all the space, if there's an interaction the wave function is altered.

Let's say the atom is ionized by a gamma ray. There'll be a large spike in probability the wave function at one point, and a corresponding drop in probability in one of the modes of the wavefunction. This electron will fly off and eventually get far enough away from the atom that you can consider them separate wave functions without too much error.

I'm glossing over (and don't fully understand) things like entanglement, and the transfer of spin here. Depending on your model, even the gamma ray was part of the wave function, and this is just the way it all evolved.

At no point is it quite right to think of the electron as a little hard ball, or particle.

To elaborate further, the a wave function exists over all space. It's a field, it's just more in some places than others. So our little electron is everywhere, but mostly somewhere. Our models usually go to 0 probability at some point and we represent different things as different wave functions. This is a simplification.

 

Or do multiple electrons combine in the same wave? I used the phrase "dancing around" because if an electron jumps around without continuous motion and appears randomly with a high probability of appearing more in one area than another, this seems like "dancing" or "sparkling" to me. What's more, I don't understand how long the thing actually appears for before it disappears and "tunnels" again, and whether it move continuously in a classical mechanical sense in between "tunneling maneuvres." If not, then it would seem to escape any possible form of force-transfer with other electrons, but that can't be possible for in the case of colliding-atoms, there has to be force-transfer through the electrons.

 

Spin made sense to me at first, insofar as a moving electric charge generates a corresponding magnetic field. So the idea that the atomic electrons are moving and therefore generate a magnetic field is consistent with the empirical observation of a magnetic field generated by a current moving through a conductor. However, once Swanson started saying that this is too classically mechanical to make sense for a quantum physics concept like spin, it seemed like I must have misunderstood.

 

Sparkling is a reasonable metaphor for a wave-function which is being interacted with, although this type of interaction doesn't really apply to atomic orbitals. Each sparkle being an interaction, after which the wave function smears out again until it is in a steady state. Again, the idea of dancing or jumping doesn't fit. Additionally it doesn't appear and disappear, it's always the same type of thing, and it's always everywhere (just mostly somewhere).

In terms of quantum objects which have some momentum, the way they move is much more akin to a ripple travelling in a pond.

 

The idea of an electron rotating doesn't make sense, that's not the kind of thing an electron is (again, your story involves something like a ball). There are some ways in which it is like an electron going around in circles, but more in which it isn't.

I've only scraped the surface of relativistic models, and still don't really have any comprehension of spin. There's another thread on this which is currently active. There are much more detailed and accurate explanations there than anything I can provide.

[steevey]

This is much better, but there is still something misleading in the way I am interpreting what you say.

I am by no means an expert on this subject, but thinking of the results of the two measurements as causally related oversimplifies the situation.

A key point is that information cannot be transmitted by this effect.

On top of that, the concept of 'when the one particle is measured' is not quite valid. In a relativistic world there is only:

An event (or here and now)

Future

Past

Other

The present isn't a valid concept.

 

My understanding of this is limited, perhaps someone more knowledgeable knows what I'm trying to say?

 

 

Information can be transmitted indirectly by this effect, in fact, so efficiently that scientists are working on computers to harness its processing power right now since silicon chips would eventually get so small that the uncertainty principal would cause electrons to "leak" out and damage or short-circuit the system. However, it isn't known that this can send information faster than light because a, there is no information being sent between the particles themselves since its just a single particle when they're entangled, and b, the entanglement collapses once its measured, and in order to re-entangle them, there would need to be a physical interaction between the two, or in other words, they would once again need to be carefully brought together again. Information is not transmitted between entangled particles because they are the same particle which means no new information can be present in just one particle in a distinguishable manner, they both exist in an undetermined state with properties responding exactly to each other, and my guess is that there would be some type of combined wave function to describe the system as a single particle much like how its used to describe two electrons with the same energy in the same shell type since all electrons are identical.

Edited March 2, 2011 by steevey

[lemur]

Let's say the atom is ionized by a gamma ray. There'll be a large spike in probability the wave function at one point, and a corresponding drop in probability in one of the modes of the wavefunction. This electron will fly off and eventually get far enough away from the atom that you can consider them separate wave functions without too much error.

I'm glossing over (and don't fully understand) things like entanglement, and the transfer of spin here. Depending on your model, even the gamma ray was part of the wave function, and this is just the way it all evolved.

At no point is it quite right to think of the electron as a little hard ball, or particle.

To elaborate further, the a wave function exists over all space. It's a field, it's just more in some places than others. So our little electron is everywhere, but mostly somewhere. Our models usually go to 0 probability at some point and we represent different things as different wave functions. This is a simplification.

 

The idea of an electron rotating doesn't make sense, that's not the kind of thing an electron is (again, your story involves something like a ball). There are some ways in which it is like an electron going around in circles, but more in which it isn't.

I've only scraped the surface of relativistic models, and still don't really have any comprehension of spin. There's another thread on this which is currently active. There are much more detailed and accurate explanations there than anything I can provide.

Thank you for engaging in an elaborated qualitative descriptive exercise for these models as you understand them. I've never been interested enough in Schrodinger's cat to read up on what it means; but I just did and it seems to have do with ontology of what the models are actually supposed to be describing. Wiki notes that Bohr didn't have any problem with confusion about the cat's status because he would assume that the cat's survival or death was independent of the processes of predicting and observing it. I don't mind discussion issues of what can be observed, known, and how but I just want to know when a particular concept/description is meant to refer to a data pattern and when it is meant to refer to the physical processes that are thought to be occurring independently of observation. I.e. when people are talking about what electrons do, I'm assuming that they are talking about how they think/model electrons to behave in unobserved situations.

 

Likewise, I don't have much interest in the mathematical dynamics of equations that don't directly describe something that is considered to be directly represented by the math. E.g. momentum describes an actual object in motion while a statistical "t test" describes a logical relationship between two means (and the means are themselves mathematical abstractions from a data set). So while a t-test may have some statistical functionality, I don't like it when I can't tell in someone's analysis whether the math they're using is describing something physical or some predictive logic of an otherwise unmodeled physical behavior. While I understand that things that happen at the sub-atomic scale are not directly observable, they are still directly model-able, at least that seems to be the case from they way I am reading your descriptions.

 

 

[Schrödinger's hat]

Steevey, your post doesn't really have much to do with what I was trying to say. Thanks anyway.

Also, you seem to be conflating quantum computing and quantum teleportation.

 

lemur

Well quantum mechanics and QED are models applicable to individual objects. That being said, the results they give are not deterministic. They will state exactly what interactions are possible for the objects they are describing, but the results will always be probabilities. Any experiment you do will follow one of the possibilities it describes, but you don't know which one. If you do a lot of experiments, the number of times you get each result will match the probabilities of the theory.

 

Once we get into QFT it's a bit different. I do not think I could explain it to you in any way which would give you the correct impression, especially as I have no more than a passing association with it myself.

 

There are other areas of quantum physics where calculating the individual wave functions is prohibitive -- namely anything involving macroscopic quantities -- and so we use statistical methods and simplification more in the way you were complaining of (not quite, as the statistics are applied to the mathematical model, not generated from experiment)

 

On Bohr and the cat:

Oh yes. I forgot to mention.

A very common view among physicists (about 30% of the ones I have discussed it with in depth, although this is not a very good sample size) is to have no english story at all, the story they tell is entirely in mathematics. They don't care what the ontological status of the cat is, or whether it's Copenhagen or many worlds. They just use the maths.

 

 

The statistics and mathematics used in other sciences are there for a very good reason. On top of integrity issues, it's very very easy to trick yourself when performing experiments by modelling your situation with simplified mathematical objects you can reason with a process which greatly lessens the involvement of your own biases and perceptions of the system.

This process is part of what I keep talking about. Scientists use whichever model or story is the simplest for the accuracy and specificity of the predictions they are trying to make.

 

I think that part of your problem may be that some science involves correlation (when variable a is changed, variable b changes too) but not mechanism (variable a is linked to these chemical processes, which induce this behavior, changing the environment to one which decreases variable b).

Sometimes if a science is new, or we are examining very complex systems (like humans) then we can find the former, but we cannot think of a good story (mechanism) to go with it.

Or sometimes we have stories, but singling one of them out and calling it correct would be premature, and non-genuine.

 

Quantum theory is, for the most part, very tight and inter-linked conceptually. There's a clear mechanism involving the other parts for each effect described. There are a few exceptions to this (why are the universal constants the numbers they are? We only determined them empirically, or why does measurement do what it does?), but not too many.

[steevey]

Steevey, your post doesn't really have much to do with what I was trying to say. Thanks anyway.

Also, you seem to be conflating quantum computing and quantum teleportation.

 

Perhaps your not understanding it because its not actually two measurements; it's only one measurement which disentangles the particles. Once again, entangled particles become the same particle. Expecting the transmission of information between entangled particles is like throwing a billiard ball and expecting some ghost twin to magically appear and do something. In an entangled system, there is no other particle, there's just the one system, so very simply I could express that as "x". So, lets say I have 2x. Now, solve for "x". Oh wait, you can't because its not equal to another value, its only one value, which is itself. If information were transmitted between them, then that means they would be distinguishable or different in some way, so then I could say 2x=20 and find out what the x is since I can distinguish the other side of the information which is 20. But that would require determining one anyway, which would collapse the entanglement.

Edited March 2, 2011 by steevey

[lemur]

I think that part of your problem may be that some science involves correlation (when variable a is changed, variable b changes too) but not mechanism (variable a is linked to these chemical processes, which induce this behavior, changing the environment to one which decreases variable b).

Sometimes if a science is new, or we are examining very complex systems (like humans) then we can find the former, but we cannot think of a good story (mechanism) to go with it.

Or sometimes we have stories, but singling one of them out and calling it correct would be premature, and non-genuine.

 

Quantum theory is, for the most part, very tight and inter-linked conceptually. There's a clear mechanism involving the other parts for each effect described. There are a few exceptions to this (why are the universal constants the numbers they are? We only determined them empirically, or why does measurement do what it does?), but not too many.

I guess I am just locked in classical mechanical thinking. To me, objects attract and repel each other using force. Electrons only make sense to me as electrostatic fields that repel each other and are attracted to protons, which also repel each other but are attracted by nuclear force and presumably gravity to some extent, although that seems negligible at the level of the nuclear particles within a single atom. Momentum of the electrons seems to be disproven as the primary mechanism for keeping them in orbit, since they emit photons and thus lose energy-levels. However, it makes sense to me that as they would get nearer to the nucleus, electrostatic attraction from the protons would increase their momentum while their repulsion from each other would keep them bouncing off each other and changing direction. Of course, since they are fields and not well-defined solid objects, they would not directly "bounce" off each other but would "bend" around each other, which would mean a certain amount of their momentum would be expressed as shape-changing. I would then assume that this shape-changing would have some kind of fluid-dynamics like what would be involved with, say, very stretchy water balloons whose density gradates toward zero from the center toward the periphery. I know this is very classically mechanical and probably doesn't fit too well with the various shapes that form at different levels, etc., but something in my head makes me want to model these things as objects in a classical mechanical sense. It seems logical to me that they behave as objects with momentum because, for example, static electricity feels like a thin layer of gas/liquid on the surface of an object. Likewise, electric current seems to behave similarly to waves traveling through a gas/fluid medium. The solidity and volume of solid and liquid matter also seems to be accountable to the structuring of electrons according to the electrostatic field of the nuclear protons. Thinking along these lines, it is frustrating when quantum theories present a barrier to further applying classical dynamics to sub-atomic interactions. I'm aware of the various arguments why these theories are correct and why classical mechanics simply fails, but it just doesn't make sense to me to let go of all relations between forces at the atomic level and those at super-atomic levels.

[Schrödinger's hat]

From a quantum perspective. Force is more of an emergent concept. Or you can think of it as rate of change of energy with respect to space, much more like the classical version. There is more than one model, even within quantum theories. QM just has potential wells which are there because shut up, that's why. QFT gets more complicated, but there is a mechanism there. I don't think going into virtual particles and force carriers at the moment would be productive. I have a reasonable conceptual grasp of these, but I'm still a fair way from learning the theory properly, so I do not want to comment in case I mislead or misinform.

Your model of balloons is a bit better, and it's understandable that you want to model them classically. That's what you know.

Solidity is also a macroscopic construct. If the interactions between your skin and an object are more frequent/more energetic than those between parts of your body, things will feel solid.

If you think about it hard, all of these macroscopic ideas will emerge from large numbers of quantum objects. In fact they have to for it to be valid. If, on the other hand, it doesn't work the other way around, I think the quantum concepts should take primacy.

Thinking about a 4d universe is very difficult and counter-intuitive at first, but over time it makes more sense. QM is much the same.

[lemur]

From a quantum perspective. Force is more of an emergent concept. Or you can think of it as rate of change of energy with respect to space, much more like the classical version.

That a very interesting idea and elegantly stated. I will have to think about it and create some permutations in the form of concrete scenarios.

 

Your model of balloons is a bit better, and it's understandable that you want to model them classically. That's what you know.

Solidity is also a macroscopic construct. If the interactions between your skin and an object are more frequent/more energetic than those between parts of your body, things will feel solid.

Also well put. Basically I picture electrons by thinking of the repellant invisible field of a bar magnet without the bar attached. I suppose it would be the attractive field in its attraction to the nucleus. So the "slippery stretch water-balloons" analogy is more like a way of describing what it feels like to push two magnets together against their same-pole repulsion. Then I just imagine that if such fields were internally cohesive due to some kind of quantum inability to split into sub-quanta, they would stretch and bend and be otherwise malleable insofar as different parts of them would be subject to different amounts and directions of force vis-a-vis different sources (e.g. one part of an electron could be getting pulled by positive charge while another part could be getting squashed by an oncoming electron repelling it).

 

If you think about it hard, all of these macroscopic ideas will emerge from large numbers of quantum objects. In fact they have to for it to be valid. If, on the other hand, it doesn't work the other way around, I think the quantum concepts should take primacy.

Thinking about a 4d universe is very difficult and counter-intuitive at first, but over time it makes more sense. QM is much the same.

Yes, it makes sense to me that objects behave differently according to the level and circumstance of interactions with other objects/substances. The same lake, for example, can easily engulf a stone dropped from 1m and completely smash a car driving off a cliff. Likewise, I have been thinking about the solid/liquid viscosity distinction and whether non-spherical objects would become viscous because they vibrate with enough energy to move relative to each other in between collisions (i.e. their shapes no longer are packed tightly enough to lock each other in). Anyway, this is just an example and shouldn't divert from the thread.

 

Btw, why you use the term "quantum object," does "quantum" refer to the necessary/natural discreteness of quantities or just to the minuscule scale of the (sub)atomic level? I sometimes feel like the two terms are used interchangeably when they shouldn't because it overgeneralizes the meaning of the word, "quantum/quanta."

 

 

[Schrödinger's hat]

By quantum object in this case I was talking about something which would be modelled reasonably accurately by a single wave-function (ie. not big enough to be collapsing its own wave-function/interacting all the time and thus averaging out quantum effects). Such as an atom, or an electron.

You're right in that it's also used to describe a discretised object.

[steevey]

By quantum object in this case I was talking about something which would be modelled reasonably accurately by a single wave-function (ie. not big enough to be collapsing its own wave-function/interacting all the time and thus averaging out quantum effects). Such as an atom, or an electron.

You're right in that it's also used to describe a discretised object.

 

A single atom can undergo a subsequent and subsidiary wave function collapse. When I observe a photon which had hit an atom in a piece of matter, the wave-particles in that matter which the photon carried information for also become determined and act more like points. This is why we don't see everything existing in multiple probable places at once.

Edited March 3, 2011 by steevey

[Schrödinger's hat]

I'm not really sure what you're getting at. If you want me to respond you'll have to elaborate/clarify a bit.