What is Meant by Electron Spin State?

No, eV (electron Volts) are a unit of energy (which is equivalent to mass). From wikipedia:

In physics, the electron volt (symbol eV; also written electronvolt according to the NIST, IUPAC, and BIPM) is a unit of energy. By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electrostatic potential difference of one volt. Thus it is 1 volt (1 joule divided by 1 coulomb) multiplied by the electron charge (1.60217653(14)×10⁻¹⁹ coulomb). One electron volt is equal to 1.60217653(14)×10⁻¹⁹ joules.

Now you might say to yourself "that's a weird way to describe mass", but actually when you consider that these particles are studied usually by smashing particles together in an accelerator, it makes sense that you would describe mass by the amount of energy needed to create it (see link below if you are confused about mass energy equivalence).

http://en.wikipedia.org/wiki/Mass-energy_equivalence

I hate pages like that..

I know enough to understand a little bit, but I don't know enough to grasp the rest of the bits I do get ;o(

And I doubt there is enough room on anyones hard drive to explain it all to me ;o(

Here's an explanation to your original question.

A spinning charged object produces a magnetic moment. If the charged object is spinning clockwise (looking at it from the top), that magnetic moment is pointing away from you (downwards), if the charged object is spinning counter clockwise (again, looking at it from the top), that magnetic moment is pointing towards you (upwards).

Now if you apply a magnetic field, the spinning object with its magnetic moment will align itself so that it's magnetic moment will line up with the magnetic field. Since an electron is a spinning charged object, all of this applies to it. It takes more energy for the electron to spin in such a way that it's magnetic moment resists the magnetic field rather than aligns with it, so that is considered the higher energy state. Left on it's own the electron would spin so that it's magnetic moment aligned with field. Two states, one lower in energy than the other.

Hope that helps,

Roger

So, how do you define the "top" on a particle ?

The magnetics direction I know from the "Right hand screw rule" - Electronics, where the current flow towards you gives CCW magnetic field around the conductor

Would the particle have a North-South "pole" ?

How does the spinning particle cope when the field is rotating? wouldn't it try to counter the spin as it tries to change direction, or is this what gives Resistance?

So, how do you define the "top" on a particle ?

Actually there is no top or bottom. Electrons are quantum mechanical particles, that means they aren't traditional particles, but rather probability distributions with physical properties. You can define the top to be aligned with the magnetic field direction. In that case the particle will have two configurations, aligned with it or opposing it. The configuration where the electron spin is producing a magnetic field that opposes the magnetic field it's in is the higher energy state, the other state is the lower energy state.

Would the particle have a North-South "pole"?

No, because it isn't a particle, it's a quantum mechanical particle which is a probability distribution with physical properties.

How does the spinning particle cope when the field is rotating? wouldn't it try to counter the spin as it tries to change direction, or is this what gives Resistance?

No, resistance is a coulomb effect. An electron in a rotating magnetic field would rotate with it, just like a classical particle would.

"Would the particle have a North-South "pole"?

"No, because it isn't a particle, it's a quantum mechanical particle which is a probability distribution with physical properties."

With all due respect I would seriously challenge the foregoing.

Either the world is real, material, concrete, made up of things we can apprehend with our five senses or various extensions thereof, or all it is, to follow after Bishop Berkeley, is a thought in gods mind.

Being a materialist and therefore an atheist I won't buy Berkeley's god's mind idea.

Hence, at the same time, I won't buy the argument that "it isn't a particle, it's a quantum mechanical particle which is a probability distribution with physical properties."

First there is in your statement an inherent contradiction, i.e., not a particle but rather some sort of quantum mechanical particle with physical properties.

You add the physical properties to the non-particle quantum mechanical thesis because you know instinctively that your quantum particle has actual physical effects on our material world.

The fact is the quantum mechanical particle that it is asserted exists only as a probability is the nonexistent beast, a mental construct created because we do not yet possess enough data to fully describe the sub atomic structure of our material universe and in the interest of discovering what we don't yet know.

The problem is many of us forget that such concepts are only workarounds for what is not yet known and hence we think of them as real things. Probability is a term to predict the likelihood of some particular incident we cannot yet actually know definitely because it has not yet occurred. It is our mental anticipation much more real then our existence as being only a thought in god's mind. But it is only a thought, a prediction, as to future circumstances of real things, real particles.

I find it interesting that there is still value in this months ago discussion. There is value because despite some of us not being able to handle the higher math usually used to deal with these concepts, the math itself probably being a factor in forgetting that these particles are real material things with real material properties, it continues to raise questions that derive, at least for me, real world answers.

In that regard, in this thread, I pointed out to someones assertion that light quanta are massless.

"Further, as I am sure you well know, light is subject to the force of gravity, i.e., the gravitational lensing effect that proved elements of Einsteins theories.

"I will emphasize once again I am not a physicist nor mathematician and probably
getting in way over my head, but it was always my understanding that gravity was
a two way phenomenon between material bodies having mass. That suggests there
may be something wrong with the issue of photons being massless.

"We also know that light only achieves light speed in pure space. In atmosphere
or various liquids or gas its speed decreases. Obviously that implies collisions between material bodies of mass."

I don't believe anybody has ever addressed that appearing material contradiction between concepts and the evidence of reality, e.g., the gravitational lensing of light.

Again, fearing I might be getting in too deep, I would assert that there can be nothing in the material universe, where all is in motion, that is without mass insofar as mass can only be the expression of its motion.

That is the value of this thread. It has caused numerous of us to try to understand materially these things that are often only expressed through the conceptual abstractions of math.

j.

You Wrote:"Hence, at the same time, I won't buy the argument that "it isn't a particle, it's a quantum mechanical particle which is a probability distribution with physical properties."

Physics is about things you can measure, nothing in your hand waving statement is measurable, it's just Philosophy. You act as if your the first person this has occurred to. Most physicists agree that Probability Distribution (wave function) representations of electron is probably the result of something deeper. We are trying to understand what that deeper idea but it takes time.

Roger,

I don't think I would use the word deeper, rather unknown, deeper has too much of a mystical connotation.

At any rate "deeper" or unknown is not the same as saying something "isn't a particle" substituting in its place "a quantum mechanical particle which is a probability distribution with physical properties."

That's interesting, but fallacious, language.

Do you agree that "probability" or "probability distribution," i.e., some sort of mental distribution of a future probable event is a mental conception of a future event? If so how can it have physical properties?

Substituting such language of predictions of the future as to any particle does not, nonetheless, make a particle a non particle composed of mental conceptions.

It does not matter that others may have spoken as I do. What does matter is that the language used in these discussions represent, as best we can make it, a true understanding of concrete reality and when we substitute instead a mental concept for something in the future or that does not yet exist, we state clearly that said mental projection, prediction, et al, be clearly labeled as such and not passed off as a replacement for concrete reality.

Your language suggest that I have pissed you off. That certainly was not my intention.

I simply insist on as literal an understanding of the concrete material universe as may be possible and that when a strictly mental conception is used in place of what we do not know it be clearly labeled as such.

Without that our discussion of concrete material reality, for that is what I think physics is all about, becomes in the hands of some folks, the agnostics, an argument that we really can't know reality, and from there it is an easy slide into the solipsism of Berkeley's god wherein the only reality is god and the thoughts in his mind without which we would not exist.

And now that I think of it, at the beginning of British imperialism, that argument allows the view that the manifold horrors inflicted on other people by British imperialism, must be alright because as ideas in the mind of the all good and all knowing god they must be alright.

j.

Here's how it is, if you're not bringing any math to this discussion, then it isn't Physics, its meta-Physics. You make very interesting philosophical points, but that isn't Physics. I'm not interested in engaging in a philosophical discussion.

If you want to talk Physics, you need to use math, that's the language of Physics. It takes time and hard work to learn, but then your ideas can be proven. What your doing is the equivalent of Monday Morning Quarterbacking.

There are physicists who would disagree with you; try the late Richard Feynman.

The history of physics, let alone of all science, starts with conceptual attempts to understand what is around us. You would seem to discard that history which itself drove the development of math.

Need I point to Newton.

What you are expressing is a sort of narrow outlook that says only those who are high level mathematicians can understand reality.

I would submit that you and your narrow adherence to math have demonstrated in your comments the fallacy of such an outlook in addition to which your comments have not at all addressed or utilized math merely attempting to explain the nature of things with an explanation derived from the colorful terms (Pun intended) that real physicists have used to identify various aspects of matter.

Further you are essentially saying that only mathematicians trained in physics can understand reality and so the rest of us butt out.

I will refrain from characterizing that politically but it should be obvious what I would say if I did.

Truth of the matter is you seem to be unable to handle the "very interesting philosophical points," which if you knew anything at all about philosophy and its history you would have recognized as not being philosophy at all which philosophy all consists of "meta-Physics" but rather the language of the science of dialectical, historical, materialism.

I am not either "interested in engaging in a philosophical discussion" but these days some of you mathematician/physicists are saying some pretty silly things because instead of starting with physical phenomena you instead attempt to predict from math said phenomena without actual, material, data.

I would not argue with much of that because obviously some of it developed, Heisenberg's uncertainty for instance, out of an attempt to get data which until now has not been available leading to concepts very much like those of Kant who insisted we can't know "the thing in itself" (An idea Mach the physicist tried to dress up in more modern terms), although these days we regularly and readily penetrate the secrets of "the thing in itself," i.e., the mind/body separation of classical (Meta) philosophy with MRI machines, or the asserted only convenient models we draw of nuclei and their particles; if you go back in this discussion you will find reference to actual photographs of such which somehow conform with our mental models, not to mention the writing conducted on surfaces at the molecular level by IBM.

You are the only one who has until now objected to the obvious conceptual discussion that has gone on here, sans, in the main, math.

But you have not yet, hiding behind your math, addressed my original comment on your comment.

Since you are the only one in this long thread who has attempted to hide behind math and the lack of it on the part of some of us, perhaps you simply wandered into the wrong place.

Nonetheless, I sure would like to hear any reply you might raise on point, most especially because your hiding behind math suggests you don't have any but in attempting such might produce something new, right or wrong, and therefore interesting.

There are among us folks who can translate almost any language into almost any other. Math is just another specialized language. I would suggest if you can't explain math derived concepts in everyday language, as Feynman was often wont to do and which he advocated, there is something wrong with your concepts but that is what I pointed too in the first place, errors in your concepts.

j.

I'm somewhere in the continuum between you two (Jack and Roger).

I taught physics, both college and high school, for a total of 32 years. I always required my students to show the math involved in solving problems, yet my limited math skills in calculus and beyond are probably what kept me from ever being comfortable with most topics in advanced physics.

I am a very visually oriented person. I rarely understand a new word (especially in foreign languages) until I have seen it written. I can't understand most concepts unless I can see a diagram or picture. I've been building electronic circuits for nearly 60 years, and designing them for at least half that, yet I can't understand a circuit with more than half a dozen components unless I have a diagram.

I have no idea which or how much of my strengths and weaknesses are a result of my education, and/or of my genetics, but I do have both. I believe those of us who have limited math skills must leave some things to those who, for whatever reason, have better math skills, as Roger must. On the other hand, I also believe it is an obligation of those folks to at least attempt to explain the results of their findings in low-math terms for the rest of us. I think Roger has been attempting to do just that.

I tend to think of everything as particles, as Jack does, yet only the wave nature of electromagnetic waves from radio to light and beyond can explain constructive and destructive interference, so a photon can't be 'just' a particle.

Like me, each of you has strengths and weakness, both in understanding and in conveying that understanding to others. Neither of you is 'right' and neither of you is 'wrong'!

I think of them as particles too, to a point, and I'm sure there's a reasonable explanation out there that will eventually clarify things for us. However electrons diffract, and so you can't always think about them as particles. They are wavefunctions, it's why that's the question.

But do they diffract as single particles?

j.

DK,

Even before I read what Roger has to say you have raised an interesting point as to particles and waves that I have been thinking about for some time.

Perhaps it is only a matter of language but beginning with the classical two slit experiment the issue of the nature of light has been posed in terms of light having a dual nature, i.e., either that of a particle or that of a wave.

I would insist, although I don't have the math, that light's nature is that of a particle despite the fact that the two slit interference patterns attest to a wave.

The fact is that light is composed of individual particles, photons.

What the interference patterns tell us is that those particles of light travel in packets forming waves just as do, say, molecules of water.

The language has made a great mystery out of the issue especially some of the extensions of the two slit that suggest supernatural conclusions as to the nature of reality.

I think in physics, as in all things, it is extremely important to follow the context and patterns of our thinking. It is too easy to get off track and digress from reality unless you do.

"I tend to think of everything as particles, as Jack does, yet only the wave nature of electromagnetic waves from radio to light and beyond can explain constructive and destructive interference, so a photon can't be 'just' a particle."

You in fact confuse, I think, the issue just as I mentioned.

The fact that the mode of travel of individual photons, particles, is that of waves, does not change the basic particle nature of light.

I have not dug into this but I have read on occasion assertions that the wave phenomenon, and hence the interference patterns, are not just restricted to sub-atomic particles. Indeed I offered one at the molecular level, i.e., water.

Now that you have me thinking about it I wonder what kind of two slit pattern you would get if instead of light you blasted cereal grains at the slits behind which you would have a sticky target?

I don't have the math and I know precisely which teacher at Brooklyn Tech was to be blamed for that. Instead of showing us the connection of algebra to arithmetic he was more interested in calling some of us "horses necks." Yes I passed algebra but only because I could replicate the pattern without understanding it conceptually.

That does not mean that I can't discern the fact that some physicists seem to proceed from the math inventing connections that they hope reflect reality but because they are not supported in front by material data may not at all, may only reflect a math conjured fantasy.

My specialty is thinking about thinking, about the process of thinking, about thinking about the process of thinking as it may apply to any subject at any time, now or in the past, most especially its path from the past to the present and derived from that its likely path into the future. So with Roger's permission I will continue to stick my nose into things here.

In that regard, since you taught physics, what would I need to replicate the two slit?

Is it possible to generate a single photon or are what they are talking about actually a string of single photons? What would I need to generate those photons. What would I need to monitor and insure that I am throwing only single photons?

If it don't cost too much let's have some fun. I have long wanted to actually see the two slit performed.

j.

What are you talking about?

We live in a world built by science. Science based on math. Science as opposed to philosophy is accountable. It can proven or disproven.

You're too lazy to put the time in to actually learn math so instead you weave some 5th grade sophistry to say it's not important. You can say anything you want, in the end if your too lazy to learn science, then don't be mad when people don't care what you have to say about it.

Don't put words in my mouth!

I probably understand better than you the importance of math to science.

Further, I am probably a better scientist than you are. That's why I understand that math is important to science but before it became so it was necessary to sweep away all the old philosophical garbage that stood in the way.

It would appear you have no understanding of the history of science and its relation to thought process hence to the physics.

Conscious, materialist, thought process is in fact a material aspect of science without which we would have no science. Some of the mind experiments, Schroedinger's Cat for instance, strictly a mental experiment, are among the most important and elegant aspects of science.

But while you rant about math you have only resorted to negative words, no math, and you put words in my mouth.

Nor have you taken up the original issue I raised.

I see you are an engineer. Engineers, by and large, apply in practice other folks equations. They are not necessarily good mathematicians or scientists.

j.

Well good, your a great scientist and I'm not, there's nothing left to discuss. Let's end this worthless exercise in compensation.

Can I just add my understanding of all this?

AAAAAAAAAAARRRRRRRRRRRRRRGGGGGGGGGGGGGGHhhhhhhhhhhhhhhhhhhhhhhhhhhh

Snaketails,

You have my sympathy.

j.