Exploring the Physics of Computer Icons: Classical vs. Quantum

[Rade]

I have a question. Are the Icons on my desktop entities that follow mathematics of "classical" physics, or are they entities that follow mathematics of "quantum physics" ? Thanks for any clarity that can be provided.

 

[masudr]

Computer icons are objects which are described by the rules laid out by the operating system's user interface (UI).

Assuming that you have a common UI (XP, OS X Aqua, Gnome, KDE, Java Desktop System etc.), these rules will not correspond to the rules of classical physics nor quantum physics.

 

[Rade]

Computer icons are objects which are described by the rules laid out by the operating system's user interface (UI). Assuming that you have a common UI (XP, OS X Aqua, Gnome, KDE, Java Desktop System etc.), these rules will not correspond to the rules of classical physics nor quantum physics.

I am not interested in "rules" but mathematics. It seems to me that position and momentum of all objects of reality must either be explained by mathematics of classical physics (chair) or quantum physics (electron) or perhaps both ??. The icons on my computer desktop are objects of reality, clearly I collapse their wavefuntion when I observe them. So my question, do the icons follow the HUP as relates to their position and momentum on my desktop ? If not then clearly QM theory is not the correct mathematics to use to describe their position and momentum. Or, are you saying there is a third mathematical physics that describes the position and momentum of the icons on my desktop (neither equations of classical nor QM physics)--if so, what name is given to this third physics (or am I just very icon challenged) ?

 

[Danger]

I suspect that you're taking things a bit too seriously here. 'Observer dependent reality' doesn't apply on a macroscopic scale. Your icons appear as they do because that's how the CPU instructs the monitor.

 

[chroot]

Indeed, look into "decoherence." To skip to the point, everything externally visible on your computer -- the phosphors on the screen, etc. -- is not capable of being in quantum mechanical superposition, because of it the enormous number of interactions it has with molecules in the air, photons of light from your desk lamp, and so on.

- Warren

 

[Jheriko]

These icons are NOT objects of reality. They only exist in the virtual world your computer creates. In this virtual sense those icons have exact and definite positions and shapes, since this data is stored in binary in both the video memory and in some settings file.

So when you observe an icon there is no "icon wave function" to change, only the wave functions of all the varying nick-nacks that make up the pixels on the monitor.

 

[vanesch]

I think that if anything, these icons are classical, because their state is given by a finite-state machine (which is a special form of classical dynamics).

 

[marlon]

I have a question. Are the Icons on my desktop entities that follow mathematics of "classical" physics, or are they entities that follow mathematics of "quantum physics" ? Thanks for any clarity that can be provided.

They are classical because "they are too big to be described by QM". I mean, they are macroscopic objects of which the behaviour is classical BY DEFINITION. If you want to have a more formal explanation i would also go for : decoherence...

Again, do NOT attach too much value to this classical physics/QM boundary. both formalisms work perfectly well within their regimes of validity. Though we do not know the exact distance scale where the QM world becomes classical and the other way around, such matters are NOT the fundamental questions that need to be asked. What matters is that both theories are completely in agreement with experimental data...


marlon

 

[Hurkyl]

These icons are NOT objects of reality.

Just to emphasize this point some more...

An icon is not a real object. Period. The thing you "see" is an abstract entity that your brain creates when you look at your monitor. Your computer is programmed to simulate the visual patterns that a real object might generate, via flashing tiny red, green, and blue lights at you.

This process happens with real objects too -- an apple redirects colored photons at your eyes, and your brain creates an abstract entity corresponding to those photons. The difference is that the "abstract apple" in your brain corresponds to an actual object in reality, whereas the "abstract icon" in your brain does not.

Another example of this is when you shine a flashlight on a wall. You see a "spot" on the wall, but there is no physical object that corresponds to that spot.

 

[Rade]

...Another example of this is when you shine a flashlight on a wall. You see a "spot" on the wall, but there is no physical object that corresponds to that spot.

Thank you, very clear. But can we then hold the same logic to be true for the quark--that is, that the quark is like the icon, and the spot on the wall, not a true "physical object" ?

 

[Rade]

...do NOT attach too much value to this classical physics/QM boundary. both formalisms work perfectly well within their regimes of validity. Though we do not know the exact distance scale where the QM world becomes classical and the other way around, such matters are NOT the fundamental questions that need to be asked. What matters is that both theories are completely in agreement with experimental data...

Thank you, but why would not a fundamental question of interest be to know the mathematics of the "exact" boundary between classical and QM theories ?

 

[chroot]

There is no "exact" boundary. Quantum mechanics becomes indistinguishable from classical mechanics in the limit of a large ensemble. The larger your ensemble is, the more accurate the agreement between the two theories.

- Warren

 

[Hurkyl]

But can we then hold the same logic to be true for the quark--that is, that the quark is like the icon, and the spot on the wall, not a true "physical object" ?

What logic?

Also, why would one think a quark is analogous to an icon or a spot on the wall?

 

[vanesch]

Again, do NOT attach too much value to this classical physics/QM boundary. both formalisms work perfectly well within their regimes of validity. Though we do not know the exact distance scale where the QM world becomes classical and the other way around, such matters are NOT the fundamental questions that need to be asked. What matters is that both theories are completely in agreement with experimental data...

That's the "shut up and calculate" attitude

 

[Rade]

...why would one think a quark is analogous to an icon or a spot on the wall?

Only to the extent that neither of the three are independent entities. But, anyway, it would appear the OP has been answered to some degree--the behavior of the computer icon, as I click on it and move it here and there, is not explained by mathematics of quantum theory.

 

[lightarrow]

Another example of this is when you shine a flashlight on a wall. You see a "spot" on the wall, but there is no physical object that corresponds to that spot.

But photons are physical objects, aren't they?
Furthermore, isn't an icon the representation of a set of transistor's states? These states, and a set of them, should be something physical (and transistors works according to QM so, maybe, icons actually obey to QM).

 

[masudr]

Photons are physical objects, but the "spot on the wall" is something the human brain abstracts as an object, not a real physical object.

 

[lightarrow]

Photons are physical objects, but the "spot on the wall" is something the human brain abstracts as an object, not a real physical object.

If you mean to see something in a spot, like a face or the moon or the american flag, then I agree with you, is not a physical object, but a simple spot has position, dimensions, intensity distribution ecc. so it should be real. Or I have misinterpreted the meaning of the english term?

 

[ObsessiveMathsFreak]

Three words:

Too much TV.

 

[marlon]

But photons are physical objects, aren't they?

Depends on how you define a physical object. I would claim that photons and let's say a tennis ball are defined in a very different way. The bal is an object in the classical sense : with finite spatial boundaries. A photon is an object with finite boundaries in an energy base (not in a spatial base). A photon is a chunk of energy, and do we observe those in the same way as we observe a car ?

greets
marlon

 

[lightarrow]

Depends on how you define a physical object.
greets
marlon

Exactly. It's not so simple to say that a spot it's not a physical object, at least not if a photon is a physical object.

Of course I'm talking about a spot which properties are objectively measurebles, and not, e.g. a spot in the coloured shadows effect.

 

[russ_watters]

If you mean to see something in a spot, like a face or the moon or the american flag, then I agree with you, is not a physical object, but a simple spot has position, dimensions, intensity distribution ecc. so it should be real. Or I have misinterpreted the meaning of the english term?

The point is that the spot doesn't fall to the floor because of gravity or get blown by wind because the spot itself is not a physical object.

All the spot is is an area on the wall that is better illuminated than other areas of the wall.

 

[Danger]

All of which also explains why the 'spot' can move faster than light if you sweep the beam rapidly.

 

[marlon]

All of which also explains why the 'spot' can move faster than light if you sweep the beam rapidly.

Indeed, that's another classic one.

marlon

 

[lightarrow]

The point is that the spot doesn't fall to the floor because of gravity or get blown by wind because the spot itself is not a physical object.

All the spot is is an area on the wall that is better illuminated than other areas of the wall.

Light IS bent by gravity.
If the spot is formed in a CRT computer's monitor, the beam's electrons are bent from gravity. In a LCD monitor it's an EM pulse instead of electrons, but it's bent too (like light).

Since most people agree on the fact that, in physics, photons do actually exist, that is, that they are physical objects, I have to think that a bright spot must be a physical object as well.

You may say that the spot it's not "the object" but an "effect" of it. I would reply that we can substitute the word "effect" with "measure".
I believe that we can't always separate a physical object from the experimental device who measures it.

 

[Hurkyl]

Since most people agree on the fact that, in physics, photons do actually exist, that is, that they are physical objects, I have to think that a bright spot must be a physical object as well.

Why? I simply don't see how they're analogous.

Light IS bent by gravity.
If the spot is formed in a CRT computer's monitor, the beam's electrons are bent from gravity. In a LCD monitor it's an EM pulse instead of electrons, but it's bent too (like light).

Light is affected by gravity. The spot on the wall is not. I don't see what you're trying to do here.

 

[lightarrow]

Why? I simply don't see how they're analogous.

If you explain me how a photon is a physical object, then I can explain you how they're analogous.

Light is affected by gravity. The spot on the wall is not. I don't see what you're trying to do here.

I simply mean that the spot moves down in the screen, in the presence of gravity, because the light's beam or the electron's beam producing the spot move down.

 

[masudr]

The spot is produced by oncoming photons interacting with the wall, and then the emitted photons, being intercepted by your retina and your brain associating these optical signals as a "spot" due to conditioning.

Do you see the difference between the photons and the spot?

 

[Hurkyl]

If you explain me how a photon is a physical object

QED says so.

 

[lightarrow]

The spot is produced by oncoming photons interacting with the wall, and then the emitted photons, being intercepted by your retina and your brain associating these optical signals as a "spot" due to conditioning.

With "spot" I don't mean the name given to the perception but to the set of photons emitted from a specific region of space.
Otherwise, I could say the book you see in front of you is not real, but only the name you give to your perception.

 

[russ_watters]

The book has physical properties that can be measured regardless of whether or not you are bouncing photons off of it. The spot on the wall does not. A simple question can demonstrate how simply wrong you are: Where is the spot? With your definition (a set of photons), the spot is a constantly flowing set of photons... but it isn't the spot on the wall.

Again, the photons are physical objects, the spot is not. Grouping the photons together does not change that. And no one mentioned it, but what you said about gravity affecting the spot is wrong too. Gravity affects the photons, but it does not affect the spot like it does a physical object.

 

[Danger]

Gravity affects the photons, but it does not affect the spot like it does a physical object.

Thanks for that, Russ. For some reason, I froze up trying to point that out.

 

[Rade]

There is no "exact" boundary. Quantum mechanics becomes indistinguishable from classical mechanics in the limit of a large ensemble. The larger your ensemble is, the more accurate the agreement between the two theories.

Thank you. But, as in the concept of the "limit" of the calculus, which can be viewed as a boundary never to be reached, would not the "limit of a large ensemble" then correspond to the "exact boundary" condition between classical and QM ?

 

[lightarrow]

The book has physical properties that can be measured regardless of whether or not you are bouncing photons off of it. The spot on the wall does not. A simple question can demonstrate how simply wrong you are: Where is the spot? With your definition (a set of photons), the spot is a constantly flowing set of photons... but it isn't the spot on the wall.

Again, the photons are physical objects, the spot is not. Grouping the photons together does not change that. And no one mentioned it, but what you said about gravity affecting the spot is wrong too. Gravity affects the photons, but it does not affect the spot like it does a physical object.

Forgive me if I keep asking about this subject. Actually I have never seriously thought that a spot is a real object, but I found it interesting to talk about it.

About where is the spot, I could ask the same about a photon. Where is a photon?