0
101 Jan 08, 2009 at 21:18

it is interesting i could not find many particle-particle simulators that simulate electrical fields even thought dynamics is pretty similar to that of planetary orbitals. there are few i could find but they are mostly 2D and defining problem in mathematical/geometrical terms, with sin/cos or some harmonic oscillator functions. none, however, i could find that simulate CLASSICAL ELECTRODYNAMICS (Stochastic El.Dynm. - SED) in 3D n-body system and even less to include MAGNETIC FIELDS, which are the effect of moving electric fields, says Lorentz and friends…

this is kind of situation and type of particles i want to simulate: http://en.wikipedia.org/wiki/Magnetic_field

what is the force behind covalent bond? what came first, chicken or egg?

Merovingian:
- You see, there is only one constant. One universal. It is the only real truth - Causality. Action, reaction.
- Cause and effect.

how wonderful,
the mystery and essence of Life, Universe and Everything lies in contradiction - the cause that is an effect of itself. ah, beautiful self-emerging craziness… im talking about field forces here, magnetic and electric.

…are magnetic dipoles the essence of Life, Universe and Everything? these dipoles would then need to be infinitely divisible while retaining its original properties, including the Yin-Yang duality, which is also kind of holographic quality, fractalous smell it has…. but, what the hell does it all mean?

ehmm, would you not think infinity goes both ways? infinite microcosmos, as well as macrocosmos… did you really think humans are on some “bottom” of grand scale of dimensions? hahaha… it’s funny because its true, but not in the spatial sense, size does not matter scale-wise.

well, if there is any meaning in this blabbering, then let it be that universe is ANALOG, rather then digital… so, these particle accelerators and search for the smallest indivisible “atom” from which everything is composed will always be futile and more and more expensive, until it causes black hole and doom us all. science is great!

…its like smashing a clock off the wall in a hope to figure out how it works,
by looking at all the broken pieces flying around.

You may have mused in the past, why one of my ….., or my girlfriend’s …. is smaller than the other? well, look at that photo above, CHIRALITY is built-in. this universe is rather quier, it pulls on one side more than on the other. breaking of the symmetry…

• CHARGES & MAGNETO-ELECTRIC FIELD FORCES -

Magnetic Fields - test1

Electric and Magnetic Fields: Positron & Electron do the helix dance

DIPOLE MAGNETIC FIELDS due to moving electric charges (not spin yet)… HydrogZen-2

HydrogZen-1, Spontaneous formation of NEUTRAL Quazi-Hydrogen atoms

• MASS & GRAVITY FIELD FORCE -

Chaos in a Box: Inverse Square and Fractal kind of Randomness

little twitching worms,
all right, lets see how does it compare…

http://www.bo.infn.it/antares/bolle_proc/foto.html

in essence,
i hope to be able to manage and somehow force these virtual atoms to aggregate with the use of “covalent bonds” by simulating it all with classical mechanics rather than quantum, which is contradictory to the “analog universe” somewhat….

anyway, any idea? any similar software out there?

#### 41 Replies

0
167 Jan 08, 2009 at 22:19

I’m no expert on quantum mechanics, but from what I know about covalent bonds, they can be pretty reasonably modeled as springs between atoms. This actually captures a fair amount of molecular behavior.

Simulating atoms and molecules accurately using classical electrodynamics is pretty much impossible, as their interactions are determined by electron structure, which is totally quantum on atomic scales. In fact it was the massive problems encountered trying to apply electrodynamics to electrons in atoms that led to the development of quantum mechanics in the first place.

Your post is kind of vague and has several different concepts in it, as well as a lot of extraneous unrelated stuff. Can you condense it a bit and be more specific about what you’re trying to do?

0
101 Jan 08, 2009 at 23:26

Your post is kind of vague and has several different concepts in it, as well as a lot of extraneous unrelated stuff. Can you condense it a bit and be more specific about what you’re trying to do?

im sorry, i was blabbering a bit, but you got the essence of it - covalent bonding

I’m no expert on quantum mechanics, but from what I know about covalent bonds, they can be pretty reasonably modeled as springs between atoms. This actually captures a fair amount of molecular behavior.

quantum mechanics boils down to geometry, which is a way to avoid speaking of forces. i can not disagree with you because most of all i know about it comes from text-books, Wikipedia and what other people told us based on their research.

but i can still ask this question:

1.) name the force responsible for covalent bond?

a.) strong or week nuclear
b.) gravity field force
c.) electric field force
d.) magnetic field force
e.) magnetic+electric field forces

Simulating atoms and molecules accurately using classical electrodynamics is pretty much impossible, as their interactions are determined by electron structure, which is totally quantum on atomic scales. In fact it was the massive problems encountered trying to apply electrodynamics to electrons in atoms that led to the development of quantum mechanics in the first place.

well, i agree that it seems so, but we can actually use this CLASSICAL mechanics for pretty much everything else except for electron orbits. electric attraction/repulsion is _the force for most other molecular interactions. we even calculate subtle changes of angles in molecules due to electron repulsion.

interestingly, i can not find any mention of MAGNETIC FIELDS in regards to chemical bonding, all they talk about is attraction/repulsion between CHARGES aka electric fields. i suppose magnetic fields could be ignored in chemical bonding?

in any case, this is indeed very, if not the most, complicated subject, so let me again boil it down to simple question:

2.) what makes two neutral hydrogen atom attract in a first place?

…it will ultimately lead to Cooper electron pairing and Pauli exclusion principle which are only rules based on indirect observation…. on the other hand, there are papers and research seem to show that classical approach can give the same results/predictions as quantum uncertainty. thought, they mostly do this with balancing ‘electrical radiation’, or something along those lines.

the point is, i can not find if anyone has tried to do it this way - as 3D n-body simulation taking both MAGNETIC and ELECTRIC fields into account - so, id like some links about it, and if there are none, then i must conclude this is a first such try, huh?

0
167 Jan 08, 2009 at 23:53

Covalent bonds are created by the electromagnetic force (but you knew that already). But (as I understand it), we can’t really understand this classically, as the negative electron clouds of two nearby atoms should always repel each other, according to classical physics. (In fact the whole notion of an electron cloud is unexplainable by classical physics.) Instead we have to understand it quantum-mechanically as a bound state of electrons in the potential well of two nearby nuclei, which has a lower energy and is therefore more stable than for two separated nuclei.

That being said, as you mentioned we don’t really need the full formalism of QM to model covalent bonds unless we need to be really, really accurate. “Semiclassical” approaches that model the bonds as classical systems with a few additional assumptions (e.g. spring systems as I suggested, and perhaps the radiation-balancing approach you mention, though I don’t know anything about it) can be pretty useful in practice. What does *not* work, however, is getting covalent bonds by simulating individual electrons using (unmodified) classical electrodynamics.

I’m not quite clear on what kind of N-body simulation you want to create - are you talking about modeling each atom as a body, with some kind of ad-hoc model for bonds, but abstracting away individual electrons? That sounds very doable, and I bet things like protein folding simulations use a technique like that. Are you talking about modeling each atomic nucleus and each electron as a body? That sounds to me like it would really run headlong into the brick wall of “QM != classical”.

0
101 Jan 09, 2009 at 00:22

Instead we have to understand it quantum-mechanically as a bound state of electrons in the potential well of two nearby nuclei, which has a lower energy and is therefore more stable than for two separated nuclei.

i suppose my problem is that i can not accept that, i see no logic there - it just doesn’t sound as explanation for anything. is that supposed to be based on laws of thermodynamics? electromagnetic force, as we know it, just does not explain it. where this energy potential came from? electric attraction/repulsion potential or some magnetic field potential?

electromagnetic force does not exist in quantum mechanics, but i do agree with you that we are nevertheless supposed to accept it is all due to electromagnetic force, which makes it contradictory for me - quantum theory positions two electrons in H2 molecule right next to each other, in between two protons.

it is almost a question of semantics - if electrons can merge or “pair-up”, than they somehow got attracted to each other, which then breaks the very definition of repulsion between like charges.

I’m not quite clear on what kind of N-body simulation you want to create

i want to simulate 4 particles.

2 protons and 2 electrons. when i run this simulation i want to see 2 hydrogen atoms form spontaneously, just like on those YouTube videos. and then, i want to see them make covalent bond that will overcome general electric repulsion between electrons and protons.

have you heard of anything like this?

0
167 Jan 09, 2009 at 00:51

Then I guess my advice to you is to go learn quantum mechanics. ;)

Sorry that I cannot offer a better explanation, but the fact of the matter is that QM behaves in a way that is totally contrary to our intuition. Unfortunately, it just isn’t easy to think about or visualize - you have to learn a whole new set of rules.

As for the simulations of two hydrogen atoms bonding, you can do that, but you have to be aware that for this purpose you CANNOT simulate the electrons as little point-particles that fly around and have a specific location and velocity. You just won’t get a covalent bond out of that sort of simulation no matter what you do. In QM the electrons have a distributed nature, where their wave function is nonzero over a large region of space surrounding and connecting the two nuclei, and they do NOT have any specific location. So if you’re interested in simulating electrons in a covalent bond you’ll have to simulate their wave functions. Unfortunately I don’t know any more details about this than what I’ve already said.

0
101 Jan 09, 2009 at 03:40

Then I guess my advice to you is to go learn quantum mechanics. Sorry that I cannot offer a better explanation, but the fact of the matter is that QM behaves in a way that is totally contrary to our intuition. Unfortunately, it just isn’t easy to think about or visualize - you have to learn a whole new set of rules.

yes, but i already know QM, the trouble with it is that is not an explanation, nor is suitable for experimentation. but also, im trying to do something that has not been tried yet.

As for the simulations of two hydrogen atoms bonding, you can do that, but you have to be aware that for this purpose you CANNOT simulate the electrons as little point-particles that fly around and have a specific location and velocity.

iam talking about 3D N-body simulation with both MAGNETIC and ELECTRIC fields. are you saying that you know of similar attempts that failed, can you point some links?

i think you are not realizing that this particular approach has actually never been considered yet. originally, classical mechanics approach was discarded at the time mostly due to complexity of the simulation.

n-body system is chaotic, it is unpredictable as much as quantum mechanics is uncertain. we can not really know if it will work or not until we try it, we have no other means to predict it but it step by step…

there are current classical methods that actually CAN DO as good QM, that is what i read on the WWW. this is not new nor against mainstream, it is just not known due to great popularity of QM.

0
167 Jan 09, 2009 at 05:41

@PlayStationX

yes, but i already know QM, the trouble with it is that is not an explanation, nor is suitable for experimentation.

I’m not sure what you mean by this, but QM does give you the ability to calculate the properties of the hydrogen molecule very accurately, and those properties can be (and have been) tested by experiment. If you’re saying it’s “not an explanation” because the interpretation of what the wave function physically means isn’t clear, that’s fair enough, but I don’t think it’s a very good reason to ignore QM entirely, as you seem to want to do.
@PlayStationX

iam talking about 3D N-body simulation with both MAGNETIC and ELECTRIC fields. are you saying that you know of similar attempts that failed, can you point some links?

I don’t know of any specific cases I can point to where someone has attempted this, but I’m not a physicist.
@PlayStationX

originally, classical mechanics approach was discarded at the time mostly due to complexity of the simulation.

I don’t think that’s true. If you consider a single atom all by itself, classical mechanics predicts the electrons will constantly lose energy and collapse into the nucleus. Since this is a two-body problem it’s analytically solvable but it utterly fails to explain the stability of real atoms. This is one of the main facts that motivated physicists to develop QM. It had nothing to do with being unable to perform complex simulations.
@PlayStationX

n-body system is chaotic, it is unpredictable as much as quantum mechanics is uncertain. we can not really know if it will work or not until we try it, we have no other means to predict it but it step by step…

That’s true enough. If you think making this simulation is worthwhile, go ahead…but I stand by my earlier statement, that I do not believe it’s possible to obtain a stable covalent bond from classical electrodynamics.
@PlayStationX

there are current classical methods that actually CAN DO as good QM, that is what i read on the WWW. this is not new nor against mainstream, it is just not known due to great popularity of QM.

Can you post a link that explains what you’re referring to? This sounds like it might be referring to one of the “semiclassical” approximations I mentioned earlier.

Edit: by the way, if you are interested in learning more details about QM, you might check out the Feynman Lectures on Physics, a three-volume set of introductory material on all branches of physics. The third volume is specifically about QM and includes treatment of the hydrogen molecule. (The link is for the whole set, but you can also get the individual volumes on Amazon. Or, if you don’t want to buy a book, you can also check your local library.)

0
101 Jan 09, 2009 at 07:20

Reedbeta,

i agree with pretty much everything you say.

i need to explain and provide evidence that classical approach can indeed show some promising results….

Quote:
Originally Posted by PlayStationX
originally, classical mechanics approach was discarded at the time mostly due to complexity of the simulation.

I don’t think that’s true. If you consider a single atom all by itself, classical mechanics predicts the electrons will constantly lose energy and collapse into the nucleus. Since this is a two-body problem it’s analytically solvable but it utterly fails to explain the stability of real atoms. This is one of the main facts that motivated physicists to develop QM. It had nothing to do with being unable to perform complex simulations.

yes, you are right. so my sentence came off not complete, not quite true.

the main reason for discard is what you say, but i was thinking of these other methods that have some theory of their own why electrons do not radiate or how they can gain energy back. so, let me correct - the computation complexity was the main reason to discard further analysis of classical approach of those methods and theories that somehow overcame the problem of “energy loss” due to “acceleration”. i say what i read in papers - that interest in this approach is back since now computers can do much more.

there are few peculiarities with radiating electron:

1.) we say when light bends due to gravity - it does not accelerate, but “follows the curvature” of space-time, is this - QM or CM? …when electron is moving with constant velocity, no matter how curved that path is, why do we not say it “follows the curvature”, but we say it “accelerates” and therefore “radiates”, what theory is this now - QM or CM?

2.) magnetic field is not quite conservative force. it acts perpendicular to velocity and distance vectors. magnetic field does not cause acceleration, even thought it causes charged particle to produce circular motion?! magnetic fields are velocity dependent, but what the hell is that velocity relative to - aether?

the second part,
well, none of it makes any sense, its simply crazy. but, that is the best interpretation about magnetic fields i could produce from Wikipedia and the rest of the WWW.

so, my hopes and my main arguments will orbit around “magnetic fields”…

That’s true enough. If you think making this simulation is worthwhile, go ahead…but I stand by my earlier statement, that I do not believe it’s possible to obtain a stable covalent bond from classical electrodynamics. Can you post a link that explains what you’re referring to? This sounds like it might be referring to one of the “semiclassical” approximations I mentioned earlier.

my theory is that when i include the “spin” of my charged particles, i would be able to model magnetic fields as strong as i wish, which could hopefully produce some overall attraction even between two electrons - if they’re spinning fast enough and they are oriented the right way - then the magnetic attraction can maybe overcome electric repulsion and further lead to some aggregation and bonding.

i will collect some links, this is the main part of my argument so let me try to find something convincing…

0
101 Jan 09, 2009 at 09:20

links… these are not my arguments. “my theory” has to do with magnetic fields, but that might come to be the same as what these guys are talking about. these are the arguments to show classical approach can be used instead of QM:

Quantum Mechanical Ground State of Hydrogen Obtained from Classical Electrodynamics

The behavior of a classical charged point particle under the inﬂuence of only a Coulombic binding potential and classical electromagnetic zero-point radiation, is shown to agree closely with the probability density distribution of Schrödinger’s wave equation for the ground state of hydrogen. These results again raise the possibility that the main tenets of stochastic electrodynamics (SED) are correct.

The following fact probably comes as a surprise to most physicists. A group of researchers in the past have both proposed and deeply investigated the idea that classical electrodynamics, namely, Maxwell’s equations and the relativistic version of Newton’s equation of motion, may describe much, if not all, of atomic physical processes, provided one takes into account the appropriate classical electromagnetic random radiation ﬁelds acting on classical charged particles. Stochastic electrodynamics (SED) is the usual name given for this physical theory…

www.bu.edu/simulation/publications/dcole/PDF/DCColePhysicsLettA.pdf

Classical Electrodynamics

Even though the Universe proves to be quantum mechanical at the microscopic level, classical electrodynamics is nevertheless extremely relevant and useful in the real world today at the macroscopic level. It describes extremely precisely nearly all the mundane aspects of ordinary electrical engineering and electromagnetic radiation from the static limit through optical frequencies.

Even at the molecular level or photonic level where it breaks down and a quantum theory must be used it is ﬁrst necessary to understand the classical theory before exploring the quantum theory, as the quantum theory is built on top of the entire relativistic electrodynamic conceptual framework already established.

http://www.phy.duke.edu/\~rgb/Class/phy319/phy319.pdf

ok, now i noticed that most of the papers i wanted to quote here are written by this guy - Daniel C. Cole. so if you search that name together with “SED” you can easily see the rest, but this is the essence of what i was referring to.

so, how does that sound?

anyway, all this still leaves the most important questions for me:

• why is no one taking MAGNETIC FIELDS into account?

• could it be that magnetic forces due to spin and velocity/direction actually can overcome electric repulsion of two electrons?

• is magnetic force stronger than electric?
how to compare the strength of magnetic and electric fields. it is hard to see where one ends and where the other begins. velocity and spin factors are confusing in these equations - we do not seem to know if magnetic field can influence motion of the particle itself…

my conclusion so far is this - magnetic fields are so mysterious and confusing that everybody wanted to forget about them, so much in fact that they invented QM just to run away from magnetism and other instantaneous forces, namely field forces.

0
101 Jan 09, 2009 at 14:13

@PlayStationX

magnetic fields are so mysterious and confusing that everybody wanted to forget about them

This is pure bullshit. Just google “quantum” and “magnetism” for an endless set of links to universities (small and unknown like Stanford) and groups (likewise small and unknown like NATO’s Advanced Study Institute) that are researching this topic.

BTW, I studied quantum chemistry before getting into computers. I would highly recommend you take a university class on this, taught by a good physicist, if you are interested; it is perhaps the hardest subject matter I have ever encountered.

@Reedbeta: Time to walk away slowly…

0
101 Jan 09, 2009 at 14:34

This is pure bullshit. Just google “quantum” and “magnetism” for an endless set of links to universities (small and unknown like Stanford) and groups (likewise small and unknown like NATO’s Advanced Study Institute) that are researching this topic. BTW, I studied quantum chemistry before getting into computers. I would highly recommend you take a university class on this, taught by a good physicist, if you are interested; it is perhaps the hardest subject matter I have ever encountered.

you are very nice person. since you are educated, maybe you can be kind some more to actually argument your opinion? i do not even know what is your objection about, huh? anyway, what did they teach you, what is the force responsible for covalent bond?

now the interesting part,
if you really have education in quantum chemistry then it only goes to prove my point since you demonstrated utter confusion about magnetic fields and everything else that you failed to understand by confusing it with “bullshit”

do you think you can actually articulate your opinion?

1.) magnetic field is not quite conservative force.

2.) magnetic field acts perpendicular to velocity and distance vectors.

3.) magnetic field does not cause acceleration, even thought it causes charged particle to produce circular motion?!

4.) magnetic field is velocity dependent, but what the hell is that velocity relative to - aether?

there you go, are you saying this is wrong or you’re saying it is not confusing? well, pick anything, its all crazy… just please explain what exactly did you imagine is “bullshit”?

Wikipedia:
- “Because the magnetic field is always perpendicular to the motion, the magnetic fields can do no work on a charged particle;

a magnetic field alone cannot speed up or slow down a charged particle. It can and does, however, change the particle’s direction, even to the extent that a force applied in one direction can cause the particle to drift in a perpendicular direction…”

…it is perhaps the hardest subject matter I have ever encountered.

i believe you that. perhaps, if you were in my class you would know better.

but not to worry, here i am now, so feel free to ask and i will explain everything to you.

first, magnetism is an abstract term in QM as explained previously. so your suggestion to look for “quantum and magnetism” is quite ridiculous in itself, are you sure you studied quantum chemistry?

0
101 Jan 09, 2009 at 15:18

@PlayStationX

if you really have education in quantum chemistry then it only goes to prove my point since you demonstrated utter confusion about magnetic fields and everything else that you failed to understand by confusing it with “bullshit”

No. I am not confused at all. I am saying that your impression that everyone “runs away from magnetism” in the field of quantum physics is absolute BS, with hints of delusion and a medium paranoia aftertaste. It may be a language barrier, though.

There is a fair amount of work being done there but, like most quantum mechanics, it is still poorly understood because of its incredible complexity.

BTW, you said in one post:@PlayStationX

most of all i know about it comes from text-books, Wikipedia and what other people told us based on their research

then later said:@PlayStationX

perhaps, if you were in my class you would know better.

So, did you learn quantum theory from class or Wikipedia? Or, are you a physics professor? (Seems doubtful. You wouldn’t be asking your question.) However, the two quotes appear contradictory…

Assuming the best-case scenario, and you are a professor, or student already in class and currently studying this, I recommend you walk down to your local university library and tap into the wonderful world of peer-reviewed physics journals, instead of expecting deep quantum theory discussion in a game development forum. Maybe they have a copy of “The Quantum Theory of Magnetism” if you need to start lower than physics and chemistry papers?

http://www.amazon.com/Quantum-Theory-Magnetism-Second/dp/9812567925/ref=pd_bbs_sr_2?ie=UTF8&s=books&qid=1231513628&sr=8-2

Now, if you want to discuss how to implement an gross approximation, or simplistic simulation of quantum forces at play (once you have your math down pat) that’s another matter and unclear from your lengthy rambling…

0
101 Jan 09, 2009 at 15:43

No. I am not confused at all. I am saying that your impression that everyone “runs away from magnetism” in the field of quantum physics is absolute BS, with hints of delusion and a medium paranoia aftertaste. It may be a language barrier, though.

hahaha.. i see now, it was a joke.

did you really think i was literary saying they were running away? anyway, just a joke.. which is funny because its true.

So, did you learn quantum theory from class or Wikipedia? Or, are you a physics professor?

there is no OR, your logic is broken, it is all about AND operator.

i learned it in class AND from text-books AND also from Wikipedia AND also from WWW AND later i was again in a classroom, as a professor… and despite all that i still can learn something new everyday, because im not ignorant.

I recommend you walk down to your local university library and tap into the wonderful world of peer-reviewed physics journals…

why? what in the world are you talking about? i did quote you mainstream info from peer-reviewed journals, whats wrong with you?

0
167 Jan 09, 2009 at 17:42

Regarding statistical electrodynamics (which I did not know about before, so thanks for pointing it out), it is an interesting approach and I think worthy of some exploration, but the Wikipedia article suggests that there is also experimental evidence that agrees with QM and disagrees with SED. I can’t see the actual paper it refers to, so I can’t begin to evaluate this evidence. Anyway, it would be interesting to see what SED has to say about covalent bonds, if you are up to the task of building a simulator for it.

0
101 Jan 09, 2009 at 18:45

@PlayStationX

did you really think i was literary saying they were running away? anyway, just a joke.. which is funny because its true.

No. I did not think your were being literal… or thoroughly accurate.
@PlayStationX

there is no OR, your logic is broken, it is all about AND operator.

Well, there’s nothing broken. It’s not a boolean expression, it’s a set of questions.

So, you are a physics professor in a University coming into a game development forum for information on modeling covalent bonding?
@PlayStationX

i did quote you mainstream info from peer-reviewed journals

I’m not asking you for generic SED quotes. You asked for a model of covalent bonding. I’m telling you the best place to get that model is to go research the model yourself from papers.
@PlayStationX

whats wrong with you?

Nothing, thanks for asking. How are you?
@PlayStationX

Nothing. I’m not complaining. I’m just saying that a) some of your initial assertions are false, and ;) this is likely the wrong forum to ask questions on simulating covalent bonds… unless you want it to be purely illustrative. I was debunking and helping, a.k.a. “tough love”, but you decided to take it the wrong way.

Here’s the “nutshell”: First, establish the model you want to represent, then come to developers on this forum and ask for help on how it can be modeled. This forum will probably not adequately answer your questions like “what makes two neutral hydrogen atom attract in a first place?”. Presumably, you know more on that than many of us here…

Have a good weekend. I’m done with this thread.

0
101 Jan 09, 2009 at 20:55

Anyway, it would be interesting to see what SED has to say about covalent bonds, if you are up to the task of building a simulator for it.

i never heard about SED either, until just recently. i too would like to know if this method can cope with covalent bonds. i suppose i could simulate it if i had equations of motion for it, which i cant quite figure out. thought, they too seem to be forgetting about magnetic force, so it is not really what im after right now.

speaking of it,
do you know of some source code or some SIMPLE and free-to-download software that can simulate H2 covalent bonding with QM(or anything), but in 3D and in real-time?

alpha,

Nothing. I’m not complaining. I’m just saying that a) some of your initial assertions are false, and b) this is likely the wrong forum to ask questions on simulating covalent bonds… unless you want it to be purely illustrative. I was debunking and helping, a.k.a. “tough love”, but you decided to take it the wrong way.

i do not mind complaining, thats cool, but if you do not point exactly what is wrong we can not really discuss it.

a.) great, but what assertions? why can you not articulate it, simply just quote what you consider false.

b.) my question is if you can help me find some links to software that deals with charges, but also with magnetic fields. i hoped it could be as easy as pointing about many different solar system software and source code for it.

Here’s the “nutshell”: First, establish the model you want to represent, then come to developers on this forum and ask for help on how it can be modeled. This forum will probably not adequately answer your questions like “what makes two neutral hydrogen atom attract in a first place?”. Presumably, you know more on that than many of us here…

you can do that when you do whatever you think those instructions are for. i think anyone past the high-school should be able to manage questions about covalent bonds and basic electromagnetic properties. and if not, then what a great opportunity to learn about it all and then use some of the crazy dynamics of electromagnets for the next-gen video game.

do not forget - magnets are fun!

…lightnings are cool, plasma is sweet. Mmmm, plasma.

0
101 Jan 10, 2009 at 01:54

Anyway, it would be interesting to see what SED has to say about covalent bonds, if you are up to the task of building a simulator for it.

let me extend this same thought on QM, what does it say about covalent bonding and where can i find a simulation of it?

not modeling/drawing tool, but real-time simulation where i can see how two hydrogen atoms approach each other and how their electron clouds change and eventually form H2. is there software like this based on QM, real-time?

i think QM computations get pretty heavy as soon as you try to do anything but hydrogen bonding. i dont really know to what extent QM can be used for simulation of bonds, as opposed to visualization of orbits for which it is good but that does not involve any interaction.

meanwhile, lets look at the QM theory…

http://www.tutorvista.com/content/chemistry/chemistry-iii/chemical-bonding/quantum-theory.php

1.) When two hydrogen atoms are at large distance from each other, there is no interaction between them. The total energy of the system is equal to the sum of the energies of the two H atoms.

2.) When the two atoms approach each other, electrons of one atom attract the nucleus of the other atom. Electrons of both the atoms are attracted by both the nuclei. These attractive interactions lead to a decrease in the energy. - NONSENSE

3.) When the two hydrogen atoms come still closer, the electron-electron and nucleus-nucleus repulsive interactions start operating. Repulsive interaction tends to increase the energy of the system. The energy of the system decreases as long as the attractive interactions are stronger than the repulsive interactions. At a certain distance there is a balance between the attractive and repulsive interaction and the system attains a minimum value. At this stage the two H atoms are at fixed distance and for m a stable H2 molecule. The inter-nuclear separation when the energy of the system is minimum is called bond length. - NONSENSE

as long as electrons repel and as long as protons repel, these two hydrogen atoms will never bond due to electric forces. maybe if they mentioned “SPIN”, like this: http://www.mikeblaber.org/oldwine/chm1045/notes/Geometry/Covalent/Geom04.htm

-“The overlap of orbitals allows two electrons of opposite spin to share the common space between the nuclei, forming a covalent bond”

…well, that makes more sense, but it should be obvious that this changes the definition of repulsion between like charges… unless that “spin” property somehow can lead to attraction or “coupling”. in any case this “SPIN factor” is very important…

now my theory should be easy to understand, it is only natural to compare these “opposite spins” of these electrons to the dipole nature of magnetic fields. in other words classical mechanics actually predicts two spinning electrons to attract if they spin in opposite directions. this seems rather obvious, but again - i do not see anyone mentioning any magnetic fields as a possible player in all this.

did i miss something here?

0
167 Jan 10, 2009 at 02:31

@PlayStationX

not modeling/drawing tool, but real-time simulation where i can see how two hydrogen atoms approach each other and how their electron clouds change and eventually form H2. is there software like this based on QM, real-time?

I don’t know of any, but then again I’m not a physicist.

As alphadog says, you are really in the wrong forum for this kind of thing. Game developers never have a need to simulate QM in games, so we don’t know much about it.

As for the bit about the electron spins, you are absolutely right that it is important. Two hydrogen atoms with the electron spins aligned cannot form a molecule; it only works if the electron spins are in opposite directions. QM explains this as due to the Pauli exclusion principle; the two electrons can’t be in the same state. The graph of energy vs separation distance between the atoms looks very different for spins-parallel vs spins-antiparallel. BTW, the diagram on the tutorvista.com page you linked shows only the case for spins-antiparallel.

I think part of the problem is the websites you are citing are not really giving you the whole story; they are simplifying so as not to overwhelm the audience. You chould check out the Feynman Lectures I linked to earlier. The third volume includes a quantum-mechanical treatment of the hydrogen molecule that accounts for the electron spins. It also doesn’t give you the whole story as it is for an introductory course, not an expert, but it gives you a lot more of the story. :)

0
101 Jan 10, 2009 at 05:27

I don’t know of any, but then again I’m not a physicist. As alphadog says, you are really in the wrong forum for this kind of thing. Game developers never have a need to simulate QM in games, so we don’t know much about it.

well, im talking about simple particle simulator with only 4 particles. i do not quite understand how can forum for master developers not be a good place to talk about this. there is plenty of stuff here about solar systems and planetary orbits…. all i was talking about is just as simple as that: F = m*a = Q1*Q2/r\^2

what is a better place to discuss real-time particle simulation?

I think part of the problem is the websites you are citing are not really giving you the whole story; they are simplifying so as not to overwhelm the audience. You chould check out the Feynman Lectures I linked to earlier. The third volume includes a quantum-mechanical treatment of the hydrogen molecule that accounts for the electron spins. It also doesn’t give you the whole story as it is for an introductory course, not an expert, but it gives you a lot more of the story.

im just simplifying and giving the first referrence that comes up on google search, but i am serious about it, so im referring to any and all available info. i like Feynman too, but he does not talk about real time simulation of magnetic forces. can you give a link to the part that might be relevant to this?

0
167 Jan 10, 2009 at 06:10

No, I can’t give a link because the book is not online :)

@PlayStationX

all i was talking about is just as simple as that: F = m*a = Q1*Q2/r\^2

Well, you asked for a *QM* simulation of the hydrogen molecule, and that’s what I was saying I don’t know about.

If you want to talk about a simulation based on SED, that might be slightly more up a game-developer’s alley.

0
101 Jan 10, 2009 at 08:04

If you want to talk about a simulation based on SED, that might be slightly more up a game-developer’s alley.

id be delighted to, if anyone can decipher formulas and express attraction/repulsion (acceleration) between two particles in some mathematical relation, then i can do all the rest.

similarly to F=m*a = G*M1*M2/r\^2 or F= m*a = k*Q1*Q2/r\^2, goal is to get acceleration ratio per time-step, after that it gets easy.

No, I can’t give a link because the book is not online

ah, yes.. i noticed afterward. i too recommend Feynman, interesting read no matter what is he talking about and there is lots of it free on the WWW, in one form or another.

anyway, even if this is not the right place i think it cant hurt to talk about physics a bit. i do not think this nuclear science is complicated at all, and you know plenty about it to throw some comments and correct me, which is good enough for me and hopefully someone else too can find this interesting and throw few cents in…

so, let me try to make a conclusion. in the light of my latest findings i can indeed confirm that this “magnetic fields theory” has never been considered, even less simulated. this is mostly due to QM “approximating” all these field forces to some uncertainty function, and unfortunately being so good at it.

one thing is for sure,
if anyone, i will not be the one to get Nobel prize for this “theory”, there seem to be more people that have thought about it in much more detail. so, here it is - this is pretty much what i had in mind and hopefully more readable than my blabbering…

“proposed theory”

According to new interpretation, every atom of hydrogen possesses an electron magnetic moment due to the electron movement. The magnetic moment of nucleus is lower so it is not important in this case. The electron magnetic moment is formed by combination of orbital and spin magnetic moment using known rules of vectors. The covalent bond means that both atoms attract reciprocally due to the magnetic interaction between their magnetic moments.

…As comparison, quantum mechanic is incapable to explain why two opposite spin are lowering the energy of system. In the same time there is a contradiction in actual theory when the electrons are filled on subshell in atomic structure and when a covalent bound is formed.

it just strikes me as very logical…

anyhow, my real and more practical problem is something else. ill share this with everyone in hope to entertain and possibly get a nice and elegant solution to this problem, here is a question for MASTER DEVELOPERS:

• imagine hundreds of bar magnets fall randomly on a floor. eventually they will orient in such way as to make complete system take on the “lowest energy” state. eg. if you put only two bar magnets next to each other they will rotate so that north pole of one is next to the south pole of another.

how would you go about simulating this?

0
101 Jan 11, 2009 at 20:22

meanwhile, somewhere else…

Sounds like the Ising model http://en.wikipedia.org/wiki/Ising_model

hey, thanks a lot! that does indeed sound like it.

now, i have to admit i have no idea how to apply it. let me rephrase the problem slightly so that hopefully we can derive some formula that can be plugged in computer….

lets image only 3 bar magnets sitting on a table randomly spaced. they can not move, but can only rotate around its center, it is 2D situation. there is no friction of any kind, no gravity and the only forces are magnetic forces. here is a picture where “x” is the point of rotation and coordinate center of each magnet, we have “top” magnet, “middle” magnet and “bottom”, like this:

[S- x -N]                                topMag: a=90, x=7, y=25

[N- x -S]              midMag: a=270, x=18, y=19

[S- x -N]                          botMag: a=90, x=12, y=4

• input are 3 initial angles and 3 pairs of (x,y) coordinates
• output are the new angles after system stabilize

1.) any idea how to derive equations to fit this case?

2.) for every initial position is there only one solution, even in 3D and with more magnets?

3.) gravity and magneto-electric fields act instantaneously on distance, right? so, is there any way to find out how quick reaction will be - how strong is rotational acceleration each instant for each magnet and how does it depend on distance?

4.) imagine now these magnets float in 3D space freely, and lets consider the middle magnet. it has a “choice” to be repelled to the right or to rotate its south pole to the left. will it rotate or will it translate? in other words, how to split acceleration to translation and rotation, what will it depend on if there is no friction and magnets are point particles with magnetic dipole moment?

0
167 Jan 11, 2009 at 22:26

I believe you can model the situation here using the equations for a magnetic dipole field. From Wikipedia, the vector equation for the far field from a magnetic dipole is:

B = mu_0 / (4 * pi * r\^3) * (3 * (M . S) * S - M)

where B is the magnetic field, r is the distance from the center of the magnet, M is the magnet’s dipole moment (i.e. a vector pointing along the south-to-north axis, with magnitude proportional to the magnet’s strength), and S is the normalized vector from the center of the magnet to the point at which we’re evaluating the field.

The equations of motion are then (from the same page):

tau = cross(M, :)

for each magnet, where tau is the torque on an individual magnet, M is the dipole moment again, and B is the magnetic field due to the other magnets (of course we don’t include the field of the magnet we’re evaluating the torque for, since it would be infinite).

Since we are in 2D, we can also say that

d\^2 theta / dt\^2 = length(cross(M, B)) / I,

where theta is the rotation of this particular magnet and I is its moment of inertia. In 3D you would have to use a rotation matrix or a quaternion to represent the magnet’s orientation and the integration is a bit more complicated.

So, to answer your question #2, yes, I believe these equations of motion give rise to a unique evolution in time for any initial conditions, even in 3D.

As for #3, actually gravitational and electromagnetic fields act at the speed of light, not instantaneously. However, if your magnets are rather heavy and weak, then their motion will not approach light-speed and you can use the instantaneous effect as a good approximation.

For #4, I am not totally certain about this but I would guess that you can actually treat the rotational and linear components independently. In other words, there is no need to “split” the effect between translation and rotation; both motions occur fully. This is analogous to what happens in rigid body mechanics when you apply a force to a point off of the center-of-mass of a rigid body. The force applies fully to the motion of the center-of-mass, but also (as a torque) applies fully to the body’s rotation about its center-of-mass. It is counterintuitive, but it is easy to see that it has to work out this way if you look at it from a conservation of momentum perspective.

0
101 Jan 11, 2009 at 23:30

ok, thanks a lot. that looks very good!

im kind of surprised with these formulas, they smell too good. im really unable to say anything, i think i need to put it in a program and visualize it to get a better feeling.

something tells me there is some problem here, inherently non-solvable, similar to how n-body orbits are unpredictable, but worse. let me do some thinking before i comment, but in any case this looks like great starting point, thanks.

As for #3, actually gravitational and electromagnetic fields act at the speed of light, not instantaneously.

that would imply that Earth orbits the point where we see sun, some point where sun was, rather than the point where sun mass is.

well, this is not really important as you say and Wikipedia seems to agree with you so i do not really see how to settle this argument, whom to believe? i believe math and geometry, and so if there is such proof i will believe that.

its just that i thought this was accepted knowledge since i also thought the gravity was measured could not be less than many many times the speed of light for some effects to explain.

what i wonder about this situation is - if magnetic fields have limited speed of propagation, would that not make our solution oscillate?

0
101 Jan 11, 2009 at 23:57

For #4, I am not totally certain about this but I would guess that you can actually treat the rotational and linear components independently. In other words, there is no need to “split” the effect between translation and rotation; both motions occur fully. This is analogous to what happens in rigid body mechanics when you apply a force to a point off of the center-of-mass of a rigid body. The force applies fully to the motion of the center-of-mass, but also (as a torque) applies fully to the body’s rotation about its center-of-mass. It is counterintuitive, but it is easy to see that it has to work out this way if you look at it from a conservation of momentum perspective.

yes, i kind of see what are you referring to, let me try to express my confusion further… this is without considering your new equations, i still need time to grasp that

the part of the trick seem to be that this is point particle, so does it mean that it can rotate instantaneously to “new” position?

[N- x -S]

[N]
[X]


say, bottom magnet is fixed and we have our OVERALL attraction, but imagine top magnet is particle at single point ‘x’, then our attraction is single vector.

obviously south pole of top magnet will stick to [N], but how fast will it rotate (angular acceleration)? how that depends on the distance between the poles? can you throw some equations for this as well or point in Wikipedia to what problem this relates to?

0
167 Jan 12, 2009 at 00:33

@PlayStationX

something tells me there is some problem here, inherently non-solvable, similar to how n-body orbits are unpredictable

N-body problems in electrodynamics suffer from the same problems as in gravitation (it is pretty much the same equations after all). The problem is not that there are multiple solutions for the same initial conditions - that is not true in classical gravitation either; both theories are deterministic. The problem is that the long-term behavior of the system depends very sensitively on the initial conditions, such that a tiny change initially creates a very big change later on. This means we often aren’t very effective in predicting the behavior of the real system due to unavoidable measurement error in the initial conditions. This is called the butterfly effect.
@PlayStationX

that would imply that Earth orbits the point where we see sun, some point where sun was, rather than the point where sun mass is.

Sure. But the sun isn’t moving at anywhere near the speed of light, so the idea that we orbit around the sun is a very good approximation.
@PlayStationX

well, this is not really important as you say and Wikipedia seems to agree with you so i do not really see how to settle this argument, whom to believe?

The fact that electromagnetic forces act at a limited speed is what gives rise to electromagnetic waves, including radio waves, microwaves, infrared, visible light, UV, X-rays, and gamma rays. If electromagnetic forces acted instantaneously none of these things would exist.

For gravity, the theory of relativity predicts that gravitational waves should exist as well, and there is strong circumstantial evidence for these, although they have not yet been detected directly.

@PlayStationX

its just that i thought this was accepted knowledge

@PlayStationX

what i wonder about this situation is - if magnetic fields have limited speed of propagation, would that not make our solution oscillate?

Absolutely. However if the magnets are relatively heavy and weak, as I mentioned before, the effects of light-speed delays are very small and can be ignored to a good approximation (the oscillations will be very weak). By the way, if you want to include light-speed delays in the simulation, you can do it as follows: when you evaluate the magnetic field at a point, rather than using the current orientation of each magnet, use its orientation at a time t in the past equal to t = r / c, where c is the speed of light and r is the distance to the magnet.
@PlayStationX

but how much will it rotate and how fast will it translate? how that depends on the distance between the poles?

Actually the poles of a magnet don’t have well-defined locations so you can’t easily define a distance between them. I am thinking of the magnets as being physical objects, like little iron bars or something, which means they have a mass and a moment of inertia and therefore take time to rotate. But those parameters (mass, moment of inertia) are independent of the magnetic properties of the object.

0
101 Jan 12, 2009 at 01:01

The fact that electromagnetic forces act at a limited speed is what gives rise to electromagnetic waves, including radio waves, microwaves, infrared, visible light, UV, X-rays, and gamma rays. If electromagnetic forces acted instantaneously none of these things would exist.

that sounds all right. is that connected to how our magnets would oscillate?

i never heard of it in that context really, so i’ll look it up, but if you can throw some links about it maybe you can save me some time.

as for the rest, i only got more confused after thinking about it, but i’ll leave all that for when i make a simulation of it.

0
101 Jan 12, 2009 at 03:12

The fact that electromagnetic forces act at a limited speed is what gives rise to electromagnetic waves, including radio waves, microwaves, infrared, visible light, UV, X-rays, and gamma rays. If electromagnetic forces acted instantaneously none of these things would exist.

after carefully studying Wikipedia article on the “Speed of Gravity”, i have to say that even thought it states at the beginning that it is that of light, the rest of the article actually gives much more evidence against such possibility.

also, i was unable to find any connection that will point limited speed of field forces would cause radiation. can you explain?

they say radiation is simply caused by acceleration, which has to do with our previous problem that magnetic fields DO NOT accelerate charged particle, while they still DO change their direction?! that is a point where either logic or language fails.

anyway,
i think it is important to make differentiation more clear here, one thing is speed of propagation of electromagnetic WAVE (photon) and possibly, completely another thing is speed of interaction of e/m FIELD.

0
167 Jan 12, 2009 at 04:30

@PlayStationX

after carefully studying Wikipedia article on the “Speed of Gravity”, i have to say that even thought it states at the beginning that it is that of light, the rest of the article actually gives much more evidence against such possibility.

What do you mean? The “experimental measurement” section of the article clearly says that all current evidence is consistent with the prediction from relativity theory that gravity acts at the speed of light.
@PlayStationX

also, i was unable to find any connection that will point limited speed of field forces would cause radiation. can you explain?

Certainly. Imagine a piece of rope. Say you and your friend hold the ends of this rope and pull it tight between you, like you were going to have a tug of war or something. Then you start moving your end of the rope up and down. You’ll create waves in the rope that you can see travelling down the rope toward your friend’s end. If you cannot visualize this I highly recommend actually trying it. :)

This is a good analogy to what happens when electromagnetic radiation is emitted. The rope is like the electromagnetic field, and you moving it around is like an accelerating charge. The motion of the charge creates a disturbance in the field that moves away (in all directions) from the charge but maintains its shape as it does so.

You can see that this depends on the field having a finite speed of propagation. If the field everywhere changed instantly when a particle moved, there would be no opportunity for waves to be created. It’s as if instead of having a rope you had a rigid metal bar. If you moved one end of it, it would instantly move the other end as well, and never change its shape.
@PlayStationX

magnetic fields DO NOT accelerate charged particle, while they still DO change their direction

Actually, in physics, acceleration means a change in velocity, and since velocity includes both speed and direction, a change in direction IS in fact an acceleration and causes radiation. This is why, for instance, particle accelerators create synchrotron radiation from a particle moving in a magnetic field.
@PlayStationX

i think it is important to make differentiation more clear here, one thing is speed of propagation of electromagnetic WAVE (photon) and possibly, completely another thing is speed of interaction of e/m FIELD.

They are one and the same thing for electromagnetic waves in a vacuum. However, for other kinds of waves such as acoustic waves (sound waves), or electromagnetic waves in a dielectric medium (such as glass or water), the distinction can be important. See: phase velocity vs. group velocity.

0
101 Jan 12, 2009 at 06:12

What do you mean? The “experimental measurement” section of the article clearly says that all current evidence is consistent with the prediction from relativity theory that gravity acts at the speed of light.

the way whole article is written leans toward your interpretation.

still, “experimental measurement” is portrayed as questionable and pretty much everything else, like 80% of the article, points to greater speed and inconsistency with experiments if it is limited to speed of light. on the other hand, most of that refers to historical interpretations and some particular famous scientist from the “past”.

so, let me describe again - it can hardly change anyone’s opinion

anyway, let me ask you why planets do not radiate gravity waves and collapse into the sun, just as electrons are predicted to radiate and fall in nucleus?

This is a good analogy to what happens when electromagnetic radiation is emitted. The rope is like the electromagnetic field, and you moving it around is like an accelerating charge. The motion of the charge creates a disturbance in the field that moves away (in all directions) from the charge but maintains its shape as it does so. You can see that this depends on the field having a finite speed of propagation. If the field everywhere changed instantly when a particle moved, there would be no opportunity for waves to be created. It’s as if instead of having a rope you had a rigid metal bar. If you moved one end of it, it would instantly move the other end as well, and never change its shape.

how about e/m fields are “instantaneous” like metal bar and e/m waves are like sound waves inside that metal?

They are one and the same thing for electromagnetic waves in a vacuum.

i guess what im saying is that there is a rope, an aether, which is made of e/m fields, they are everywhere and there is no such thing as vacuum in that respect. e/m waves are just that, some deformation/vibration pulsating in the “sea” of e/m fields. this does not mean e/m fields act instantaneously, just makes difference between “medium” and “localized state of medium”.

well, im not quite sure if there is any point talking about this really, i wish there could be some agreement on what kind of reference we can both agree on, so then we can simply quote that reference and finish the argument.

as for spinning magnets,
im still struggling with torque equations, i have no idea how to compare results to the real-world? how to make the test case?

isn’t there some java applet with rotating bar magnets?

Actually, in physics, acceleration means a change in velocity, and since velocity includes both speed and direction, a change in direction IS in fact an acceleration and causes radiation. This is why, for instance, particle accelerators create synchrotron radiation from a particle moving in a magnetic field.

“a change in direction IS in fact an acceleration” - that is exactly what i am saying. so, it is absolute contradiction to say magnetic field can change direction, but can not accelerate.

its just one of those things we have to accept, its not like we have a choice here as with “speed of gravity”, which is not really important since our equations work without that part anyway.

the other option is to simply give a new name for this type manifestation.

0
167 Jan 12, 2009 at 06:40

@PlayStationX

still, “experimental measurement” is portrayed as questionable

I would disagree with that. The consensus today among professional physicists is that the current experimental evidence is not in conflict with the prediction of gravitational waves. There is also evidence, for instance the orbital decay of the Hulse-Taylor system, that would be very difficult to explain without gravitational waves. Plus, the prediction comes straight from general relativity (GR), which is an extremely well-tested theory of gravity over 90 years old. GR has done so well in the past that no one really expects it to be wrong about this subject.

That being said, it is true that we have not yet directly detected a gravitational wave; however, this does not falsify of the idea because of the limitations of current experiments - specifically, that they can only detect high-frequency gravitational waves, which if they exist would be relatively rare. There is an experiment, LISA, in the planning stages now, which would be able to detect low-frequency gravitational waves as well.
@PlayStationX

pretty much everything else, like 80% of the article, points to greater speed and inconsistency with experiments if it is limited to speed of light.

I think you may be confusing the historical development of gravity theories with the current consensus. The various theories discussed in the article are not to be taken as being equally valid. GR is the premier theory of gravitation today and it predicts that gravity acts at light-speed. The fact that gravity acts instantaneously in Newtonian gravity (for instance) should not be taken as conflicting with GR - rather, Newtonian theory is an approximation that is only valid when discussing weak gravitational fields and slow-moving objects, in which case instantaneous gravity is a very good approximation.
@PlayStationX

anyway, let me ask you why planets do not radiate gravity waves and collapse into the sun, just as electrons are predicted to radiate and fall in nucleus?

According to GR, they actually do radiate gravitational waves. However, they would lose energy very, very, slowly, so that it would take an extremely long time (trillions of years, at least) for there to be any noticeable effect on the orbit. However if you look at orbital systems like binary stars, such as the aforementioned Hulse-Taylor system, the fact that the stars are much more massive and closer together than the Earth and Sun makes them radiate much more strongly. And we can actually measure the decay of their orbit due to emission of gravitational waves.
@PlayStationX

how about e/m fields are “instantaneous” like metal bar and e/m waves are like sound waves inside that metal?

This is inconsistent, because if an object is truly rigid you can’t have sound waves in it. After all, sound waves are just mechanical movement of atoms relative to each other, and in a truly rigid object the atoms can’t move relative to each other.

Of course, real objects are never truly rigid, but in metal the sound waves travel very quickly, thousands of miles an hour.

@PlayStationX

i guess what im saying is that there is a rope, an aether, which is made of e/m fields, they are everywhere and there is no such thing as vacuum in that respect. e/m waves are just that, some deformation/vibration pulsating in the “sea” of e/m fields.

Yes, this is accurate.

@PlayStationX

as for spinning magnets,
im still struggling with torque equations, i have no idea how to compare results to the real-world? how to make the test case?

Heh, unfortunately I can’t help you with that one. I’m a theoretician. :)

0
101 Jan 12, 2009 at 07:26

I would disagree with that. The consensus today among professional physicists is that the current experimental evidence is not in conflict with the prediction of gravitational waves.

i agree that applicability of that theory is good enough basis to believe that the rest, less proven, aspects of it could be taken as true.

it is only my feeling that all the trouble about great unification of theories comes out of lack in understanding about field forces, so im simply refusing to believe what does not come intuitive to me, until there is some more practical evidence. by ‘practical’ i literary mean “possible to simulate”.

that’s it then, we settled it.

just those magnets then… awwwwwww. equations, algorithms, ideas are welcome.

meanwhile, this is what im trying to get my head around…

those new equations do have cross product, so there is some “right hand rule” going on there and there is something being perpendicular to something else.

however, from my real-life experience i think that i saw magnets attract each other in straight lines? do they not?

i mean what am i to expect when i place two magnets in free space like this:

[N- x -S]          [N- x -S]


should they connect in a straight line like opposite charges would, or should they “wiggle” and kind of spiral toward each other?

i mean, how do i know whats bug and whats not… hahaha!

0
167 Jan 12, 2009 at 17:36

Yes, those magnets move toward each other in a straight line. In this case since their directions are aligned the cross product will be zero and so there is no torque, and no rotation.

0
101 Jan 12, 2009 at 18:38

Yes, those magnets move toward each other in a straight line. In this case since their directions are aligned the cross product will be zero and so there is no torque, and no rotation.

are you saying that if there was some initial angle they would not connect in a straight line? its just that i never experienced it, shame i do not have any magnets here.

i know they wiggle when they repel, but i never noticed they wiggle when they attract. this leads to question if the line of attraction between metal and magnet is a straight line or not?

what is the difference?

take a neutral metal molecule and take some charged non metal molecule with the same mass. how trajectories of non-metal ion and neutral metal molecule differ as they are attracted and travel towards magnet?

what part of metal molecule is responsible for attraction - electron/proton charge, or their magnetic moment?

0
101 Jan 12, 2009 at 19:46

i was trying to answer my own questions when i stumbled over something that will throw us few steps back.

http://en.wikipedia.org/wiki/Earnshaw%27s_theorem Earnshaw’s theorem states that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges. This was first proven by Samuel Earnshaw in 1842. It is usually referenced to magnetic fields, but originally applied to electrostatic fields. It applies to the classical inverse-square law forces (electric and gravitational) and also to the magnetic forces of permanent magnets and paramagnetic materials (but not diamagnetic materials).

the way i read this is that n-dipole-body system does not actually have unique solution… or, it means solution oscillates and if it oscillates(regardless of any speed limits), then is it regular in amplitude or is it some chaotic oscillation?

i still think this is not the same kind of chaotic, but predictable problem as with n-body orbit. whether chaotic or kind of oscillatory, i think n-dipole system actually could be non-deterministic, which could explain the need and practicability of QM and uncertainty.

next, i think we need to separate these distinct case:

1.) magnet dipole - magnet dipole
2.) magnet dipole - electric charge
3.) magnet dipole - metal molecule
4.) magnet dipole - charged metal molecule

the problem with all of them is that it is really impossible to separate magnetic field from electric, so lets take 1st two case as example…

#1 - we take some equation to calculate dipole-dipole magnetic attraction, but as soon as they start moving towards each other they will produce some electric (radiation too perhaps) property, which is not accounted for in original equation we started with.

#2 - we take some equation to calculate dipole-charge attraction, but as soon as charge starts moving it will produce magnetic moment, which is not accounted for in original equation we started with.

#3,#4 - similar to above…

obviously im very confused about it all, much more then i was few days ago when i thought i know a lot about magnets… it turns out - i know nothing

help!

0
101 Jan 12, 2009 at 20:30

Just a quick suggestion: Try real physics textbooks and journals, instead of piecing together stuff from Wikipedia…

0
101 Jan 12, 2009 at 22:04

Just a quick suggestion: Try real physics textbooks and journals, instead of piecing together stuff from Wikipedia…

are you saying you know the answer but you will not tell us?

Wikipedia does contain knowledge from the textbooks and to my knowledge they actually try to keep it updated and that they have considered many of the textbooks before they wrote the articles.

in that respect Wikipedia should/could be more objective and complete reference than the printed “real” textbooks.

in any case, i do have quite a few real physics textbooks as well as access to the rest of the Internet that is not Wikipedia, including all the scientific journals, articles, peer-reviewed published papers as well as non-published…

i can not find the answer, so can you please tell us?

0
101 Jan 12, 2009 at 22:10

No. I would not be able to spit out a model from memory.

I’m just saying that you may be better served by going to high-level textbooks because the level of detail and understanding you want or need is not going to be in Wikipedia. Wikipedia is good for “summary” information, and as a “kick off” place to start your deeper research.

At least, that’s what I would do.

I had another thought: you may want to search for “demo scene” forums too. These folks frequently adapt scientific concepts like fluid dynamics, Conway’s Game of Life, etc, into graphical representations…

0
101 Jan 13, 2009 at 02:09

I had another thought: you may want to search for “demo scene” forums too. These folks frequently adapt scientific concepts like fluid dynamics, Conway’s Game of Life, etc, into graphical representations…

thank you.

any information that can bring me closer to answer is welcome. can you give a link of that forum please?

i still think that im asking some very basic questions. i mean half of these could be answered by anyone who have some magnets at home.

the other half i thought i would have no trouble finding info on Wikipedia, even less on the whole world wide web, i simply ask how magnets attract - in spiral or straight line. i thought i knew, i thought they told me that even back in high-school, but i now realize i really have no idea about it.

i mean, im only asking if your fridge magnet spirals as it travels to your fridge door?

mine seem to go straight line, but they are so weak and i can not judge what happens in that small distance, such short time.

0
101 Jan 13, 2009 at 03:25

@PlayStationX

i simply ask how magnets attract - in spiral or straight line.

Although I have studied QM, I basically know enough to know I don’t know anything about magnetism. :)

At any rate, your posts confuse me in their rambling. Assuming what you basically want is captured by my quote above, I would recommend you read up on Maxwell, Lorentz and Faraday…

http://en.wikipedia.org/wiki/Lorentz_force (Since you love Wikipedia! B))

http://musr.org/\~jess/hr/skept/E_M/E_M.html

And, when I refer you to papers, it is because the equations above are both mathematically accurate and deceptively simple-looking. Here’s an example of a quick paper I dug up in five minutes of looking:

This is what I mean by “what are you modeling?”

0
101 Jan 13, 2009 at 04:33

Although I have studied QM, I basically know enough to know I don’t know anything about magnetism.

its not your fault or anyone else’s. its my fault because i was born too late, but i’ll fix all that…

this just sounds weird because we have these silly little things on our fridge door, we use them in almost anything that has to do with electricity… yet, we have no idea how it works and what is it made of.

still, we can indirectly observe what it can do to material world, the “particles” we can see and measure. so, i actually think most of my answers are there, they are just not formulated in this way, it is just hard to “google”.

sweet, sweet mystery. Mmmm Mystery…

its one of those things… and here’s another one! this one will sound as trivial as magnet, but, to me, is equally mysterious! MOONS… moons, moons, moons… All these moons are yours, except Europa. Attempt no landings there.

the impossibility of moon formation due to only gravity force is as unlikely as is attraction of two neutral atoms due to only electric force. we have no idea how our moon happened, now… where the hell did all the other moons come from? …and imagine, they are so nicely packed in rings?

did not we say that n-body system is chaotic? what’s up with all the planets lining up, and where did all the moons come from, why is everything in such order?

This is what I mean by “what are you modeling?”

im modeling Universe, Life and Everything, the Matrix itself - ELECTROMAGNETIC FIELDS, all there is and that what you call ‘real’.

Alpha:
- This…. this isn’t real?

What _is real? How do you _define real? If you’re talking about what you can feel, what you can smell, what you can taste and see, then real is simply electrical signals interpreted by your brain.

i already use Lorentz equations, thank you.
Reedbeta gave formulas i was looking for, now i only need some visual or textual reference of real-world to compare with my simulation. at this point i do not know if i have bugs or not, i simply need something to compare it to, unless you want to implement it for me and guarantee somehow formulas indeed work? ;-)

did you see this link in the OP, its very readable and illustrative: http://www.phys.unsw.edu.au/PHYS1169/beilby/magnetism.html