Can quantum theory be explained?

[Kane O'Donnell]

There must be a reaon WHY things happen

This is a *very* loaded statement, Cheman - can you prove this? Also, this creates an infinite chain - if there's a reason why things happen, then there must be a reason why there's a reason why things happen, etc etc...in which case, doesn't the idea of a 'reason' become a bit fuzzy?

it would be better to introduce the theory before bombarding peoople with complex math

They do, at least at most of the Australian universities. It's very painful for people who take a parallel maths stream, in my experience. On the other hand, this allows people who aren't going to actually *contribute* to quantum mechanical theory but need to have a good grasp of it in their field (photonicists, some electrical engineers, chemists) to keep up with the physics students. I would have preferred, during my 3rd year, to have had an advanced QM course taught at a higher level for students with a strong mathematical background.

Theres plenty of maths forums if you want to go over the symantics of a theory

I want to point out here that a lot of the thread wasn't about the semantics of the mathematical framework but with the idea of 'understanding' and 'explaining' and so on. This forum is an excellent place for such a discussion, since QM is almost (*almost*) unique in the number of headaches it gives to people seeking simple explanations (I'd whack SR/GR in this category too).

If your not shocked by Quantum Mechanics then you have not really understood it properly

This is an often-quoted saying, but a lot of us have grown up with quantum mechanics and are therefore a hell of a lot less shocked than some people think we should be. I believe the statement was made by Bohr around 80 years ago, maybe it's time it should be re-evaluated. QM has become somewhat stranger since Bohr made the remark - it's not immediate that Bohr would be in a position to make such a statement given the advances made over the last 80 years.


Regards,

Kane O'Donnell

 

[Cheman]

"who aren't going to actually *contribute* to quantum mechanical theory but need to have a good grasp of it in their field (photonicists, some electrical engineers, chemists) to keep up with the physics students."

Hmmm, surely its a different type of contribution?! Afterall, fine the "maths heads" can work stuff out which makes our ability to do things much easier but it gives us understanding of what things are really like - that is the contribution that eg chemists make. We can actually SEE and PICTURE what is going on. Eg - take an atom; what your saying is that it is ok to describe an atom as a load of maths. Fine - but what does that mean its actually like?! It seems that quantum mechnics has all the maths and knows what it does but doesn't know what it is referring to, etc. Correct me if I am wrong.

 

[Kea]

maths of QM

It seems that quantum mechnics has all the maths and knows what it does but doesn't know what it is referring to, etc. Correct me if I am wrong

In fact, the mathematics of QM is relatively simple by today's
standards. If one wants to REALLY understand QM one should
at least know the maths in which it was formulated in the early
20th century. Many physicists have a better idea of what QM is
referring to than they have the maths with which to formulate
it...but this just leads to MORE maths...

Kea

 

[Eye_in_the_Sky]

If your not shocked by Quantum Mechanics then you have not really understood it properly

This is an often-quoted saying, but a lot of us have grown up with quantum mechanics and are therefore a hell of a lot less shocked than some people think we should be. I believe the statement was made by Bohr around 80 years ago, maybe it's time it should be re-evaluated. QM has become somewhat stranger since Bohr made the remark - it's not immediate that Bohr would be in a position to make such a statement given the advances made over the last 80 years.

Yes, it was Bohr who made such a statement.

... For the record, here are three more (more recent) quotations:

Feynman (1964)

I think it is safe to say that no one understands quantum mechanics. Do not keep saying to yourself, if you can possibly avoid it, "But how can it be like that?" because you will go "down the drain" into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that.

Gell-Mann (1981)

Quantum Mechanics, that mysterious, confusing discipline which none of us really understands but which we know how to use.

Feynman

What I am going to tell you about is what we teach our physics students in the third or fourth year of graduate school ... . It is my task to convince you not to turn away because you don't understand it. You see my physics students don't understand it ... . That is because I don't understand it. Nobody does.

--------

On another note, here are two more quotations of Feynman regarding the role of Mathematics:

One cannot understand ... the universality of the laws of nature, the relationship of things, without an understanding of mathematics. There is no other way to do it.

To those who do not know Mathematics it is difficult to get across a real feeling as to the beauty, the deepest beauty of nature. ... If you want to learn about nature, to appreciate nature, it is necessary to understand the language that she speaks in.

 

[Kane O'Donnell]

Yep, I'd agree with the 'no one understands it' approach.

Cheerio,


Kane O'Donnell

 

[tavi_boada]

QM can be understood!(?)

I think it's somewhat arrogant to say we understand classical physics. First of all, what worries me less of QM is the discreteness of some magnitudes, e.g. energy of electrons in H atom. There are many examples of discrete energies in Classical Physics such as a rope oscilating with its endpoints fixed (many equations with suitable boundary conditions yield discrete values).

Why, then, do people claim QM is not understandable? Or why do people say its indeterministic? Amplitudes are completely determined by the theory. Can you explain further why you say QM is not understandable?

I'm sorry if I've said things already posted, I haven't had time to read all the posts.

 

[Kane O'Donnell]

Why, then, do people claim QM is not understandable?

What I'm referring to is that we can't, in QM, say *why* the mathematical framework is the way it is (with probability amplitudes, wavefunctions, operators, etc). We've made a lot of progress, in fact, in explaining the 'why', but unfortunately for those who crave an explanation in simple pictorial form or something like "balls travel in a wind-bent parabola because of gravity", the (partial) explanations of the 'why' in QM are mathematically quite sophisticated.

For a simple (ish) example, why do we want self-adjoint operators? Well, from linear algebra we know that in finite dimensions SA operators have real eigenvalues. We know that this can be generalised to bounded operators on an infinite dimensional space too. Real numbers are the only kind we can measure, so no wonder we want real eigenvalues if we're interpreting eigenvalues as the measurable values of an observable. Problem is, there are *lots* of unbounded operators, including the momentum operator, the kinetic energy operator and hence the Hamiltonian.

We already know that the TISE works magnificently well for some systems. As such, we really, really want to have some reason why this unbounded operator (the Hamiltonian) has a real spectrum for a wide variety of potentials. If we can do this, we will be able to write down a more general QM axiom that tells us the class of operators we are allowed to use as observables in QM. (obviously, since non-relativistic QM has been studied in depth for years, we would guess that the answer is already known, and it is).

It turns out that the notion of self-adjoint generalises in the unbounded case, although in order to generalise we have to restrict the class of wavefunctions upon which the operators can act. This is excellent, because the restriction, usually, is to require that the wavefunctions be continuous and differentiable to some degree, hence explaining the requirement for a continuous/differentiable wavefunction without referring to infinite energy gradients and so on (the latter explanation is sort of a circular argument, I would guess).

Ok that got a little technical at some points, but I hope it's a reasonable example as to what explanation might mean when we try to 'understand' quantum mechanics. In this sense, we don't understand QM, because it's mathematical framework is not fully understood as being a requirement of some underlying conditions.

Regards,

Kane O'Donnell

 

[tavi_boada]

Are you saying that people say they don't understand QM because of the problematics of unbound operators being self adjoint?

 

[dextercioby]

Are you saying that people say they don't understand QM because of the problematics of unbound operators being self adjoint?

No,that part of QM is perfectly understood.I'll post again the famous quote from Feynman:
"I think it is safe to say that no one understands quantum mechanics".
My guess is that the key word from phrase is not "understand",but "safe".Feynman must have meant:Okay,let's assume the situation in which some individual claims he masters QM,he understood it.But then,another guy comes to him and says:"Hey,use your QM knowledge to explain this..."(and gives him an example).And so our "QM expert" makes a fools outta himself,as he cannot explain some awkward phenomenon.

So all of us theoretical physicists should "play it safe" and say that we don't really know every aspect of this theory and moreover we cannot give answers to the fundamental question "why?".

Daniel.

 

[Kane O'Donnell]

Are you saying that people say they don't understand QM because of the problematics of unbound operators being self adjoint?

No, it was just a simple example that hopefully illustrated the kind of things theoretical physicists *do* when they're investigating a theory in order to try to 'understand' it.

Kane O'Donnell

 

[Louis Cypher]

Yes, it was Bohr who made such a statement.

... For the record, here are three more (more recent) quotations:

--------

On another note, here are two more quotations of Feynman regarding the role of Mathematics:

Thanks for putting me straight on the ins and outs; yes precisely my point although rather cryptically made do not try to understand what we cannot yet understand is perhaps a dangerous way of looking at things, with the current understanding it beehoves us to find ways to understand the mysteries whether we are able to really see what's going on after all that's what science is about; maths is usefull in giving us an appreciation of a theory if we are mathematically inclined and experiment is taking said maths and then seeing if its congruent with reality both are to be applauded; though one should be carefull in making predictions based on predictions; the house of cards thing; because say qm is wrong then surely string theory is wrong by an order of magnitude and m theory well now were possibly in the realms of the absurd; much as I like the simplicity of string theory it's tenuous existence rests solely in the hands of mathemeticains who in my opinion are being driven slowly insane by there incomprehension of the infinite and the infinitesimal.

I think we should take a long ahard look at that which we hold true and try and proove that b4 flying off into a philosophical debate about strings,I'll leave that to the Doctors of Philosophy. PhD fellows after all there eminently more qualified to explore it than I.

Facinating though theories are at the end of the day there just theories, like the Theory of Gravity, one day someone will find the flaws in QM and it will come crashing to the ground replaced by a new mechanics simillar but closer to the truth; God help us if we ever reach a point where we find the truth, I'd have to give up my degree because there'd be no future in physics

Nice quotes like it.

 

[lawtonfogle]

If we found the truth would we want to know it.

The truth might be better off never being found.

The government keeps secrets from the public for its safety. If the public ever found out about a (lets just say, nuclear threat from terrorist) there would be a panic.

Who says this 'truth' is not the same.

 

[Louis Cypher]

I think your missing the point here, natures truths are beautiful and we would benefit greatly from knowing them, I don't necessarily need to know if a major terrorist threat has been averted at the time, because the panic caused by said threat would be counter productive to intelligence gathering.

To catch a glimpse at how the universe would be great, nature cannot keep secrets from us forever just like governments can't keep secrets indefinitely, people have a way of hearing the truth all be it an objective truth - or an obfuscated and fudged truth in the case of governments - sooner or later, but is it truth?

Anyway enough philosophy

 

[kristobal hunta]

time has not come yet

Right now QM is more describing than explaining. Actually its authors never put the goal to explain why it happens, instead they just tried to make predictions what would happen in the experiment. And this is normal. Newton first make mathematical model for gravity, but only after Einstein we know that it is explained by curvature of space-time...well now we have to wait until somebody would explain to us what the space-time is and so forth...

I mean don't try to make mechanical models of QM or trying to understand it. First you need to feel it mathematical sense and later maybe you would feel like you "underdstand" it.

Maybe in another hundred years there will be an answer to your question. And the rules of QM would be just a simple consequence of space-time properties or whatever...

 

[Louis Cypher]

Maths

Personally I think the problem with QM is divide between the mathemticians and the experimentalists.

A good pysisist is both, getting tanlged up in mathematical somantics is fine and worthy work but if that's all you do then your wasting your time; pure maths is pointless for a physisist after all aren't we really asking a simple quiestion abput everything, and if so don't we need to put our elgeant theories to some practical use? Einstein was relatively poor at maths compared to his colleagues so he got them to do the maths for him and then when he learned to be more fluent in maths he invented mathematics to explain his theories, his outlook as a Scientist was to theorise and then experiment and then invent formulae it bemuses me that people now do the reverse ? both is fine but both need to be done by all surely, It's no longer science mathematics its philosophical sophistry it seems. Fine if your doing a PhD but innapropraite for most

 

[trosten]

In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move.
Douglas Adams

I just want to say its great that someone quotes D. Adams if u really want to know what's going on I think his books can help you.

In the beginning I started studying QM to learn why the world behaves they way it does, is there a god etc. Now I find myself studying it because I am stunned by the way the world behaves, its just simply amazing.

I aslo feel that Bell with the Bell inequality made it clear that there is no answer to the question why things behave the way they do.

 

[godzilla7]

I meant no offence about the maths heads, just a little more explanation than maths would have been nice or some sort of description of the concepts. Anyway, I used the shocked quote to convey the way I felt when I first had to get to grips with the weird world of QM, I didn't mean it to be taken in its original context, perhaps I should have made that clear. And unfortunately in England there isn't the choice to avoid some of the more theoretical maths, the first year is always spent going through the complex anture of classical and quantum maths, sa shame I think it would be better to run through the maths after exploring the concepts, so as not to scare people off and to tweak there imagination, show I'm learning and it helps to have a grip of the aplication of maths before you fully understand it I find the reverse way more stimulating and infinitely more interesting than the rather dry pure maths ythat are the precursors to the course.

 

[misogynisticfeminist]

I meant no offence about the maths heads, just a little more explanation than maths would have been nice or some sort of description of the concepts. Anyway, I used the shocked quote to convey the way I felt when I first had to get to grips with the weird world of QM, I didn't mean it to be taken in its original context, perhaps I should have made that clear. And unfortunately in England there isn't the choice to avoid some of the more theoretical maths, the first year is always spent going through the complex anture of classical and quantum maths, sa shame I think it would be better to run through the maths after exploring the concepts, so as not to scare people off and to tweak there imagination, show I'm learning and it helps to have a grip of the aplication of maths before you fully understand it I find the reverse way more stimulating and infinitely more interesting than the rather dry pure maths ythat are the precursors to the course.

agreed, i strongly believe that the conceptual foundations of QM should be presented non-mathematically before the math comes in. I believe that this helps students appreciate the theory better and realize that there's much beauty undelying quantum mechanics other than elegant mathematics or excellent predicting power.

 

[ZapperZ]

agreed, i strongly believe that the conceptual foundations of QM should be presented non-mathematically before the math comes in. I believe that this helps students appreciate the theory better and realize that there's much beauty undelying quantum mechanics other than elegant mathematics or excellent predicting power.

In the Malay/Indonesian language, there is a word to refer to a singular third person without referring to his or her gender. The word is "dia". However, this word does not exist in the English language. I cannot refer to a singular third person easily without knowing that person's gender, or making either tedious, or awkward, or impersonal-sounding statement, such as using "he/she", "that person", etc.

Now, what does THAT have to do with what you just said? I'm trying to illustrate the fact that it is a distinct possibility that QM is describing something in which our currrent "language" or understanding has no ability to accurately convey! Our understanding, concepts, and qualities are inherently tied to the classical world that we already understand, such as the meaning of "position", "momentum", "energy", etc... Yet, such concepts may have vague, or even faulty meanings when we try to apply that in the QM realm. I am convinced that it is why when we measure these things, they give us "weird" answers. You are forcing a square block through a round hole, and you get an outcome that has the appearence of a square block, but with chopped corners. Yet, we complain about the round hole, never the fact that we had square blocks in the first place that wasn't MEANT to be passed through a round hole.

QM isn't supposed to make classical sense. That's the whole point! Therefore, how does one convey the "conceptual foundation" of QM without having the mathematical rigor first? If you have paid any attention to the quackeries on here, you will have noticed that most of them have the impression that they understand the concepts of QM, and yet, lacking severely the mathematical understanding of what it is. This usually results in outright bastardization of what QM is and often leads to hysterical conclusions.

So no. I disagree with the assertion that one must first teach and establish "conceptual understanding" of QM before any mathematical description. For most of us who have gone through the process, our "conceptual understanding" of QM is still evolving and hopefully, progressing. To think that one can simply describe in words the conceptual foundation of QM is to trivialize the complexities of QM, and to "dumb down" the intricate details of its description. I do not see anything good coming out of that for students about to learn the subject.

Zz.

 

[misogynisticfeminist]

I do understand what you mean Zapperz and i myself have come across "quackeries" where QM is concerned. But actually, establishing the context of what I said, I meant that non-mathematical descriptions of "conceptual foundations" be introduced first to incite curiosity and excitement amongst those who learn them.

In fact, it was the counter-intuitive nature of QM that first attracted me to physics. But of course this does not undermine the importance of mathematical rigour in really understanding QM but I think that before you learn something, you got to get excited about it first.

I do not see non-mathematical descriptions of QM as a suitable substitute for a mathematical course and the education of someone studying QM is FAR from complete without the math. But like i said, the purpose of non-mathematical descriptions is to incite curiosity.

 

[godzilla7]

Yes I am not arguing that you should forgo the maths simply that as Misogynistic Feminist said, you encourage some excitement and wonder in students before, bombarding them with maths, what I'm suggesting is that for the first 3 months of say a degree, they learn the quantum and classical applications of physics, and the application of this on the astronomical scale, doppler effects simple mathematics like parsec equations and photon energy math, relativity, special relativity, nuclear physics, stuff to show the vast application of physics, to encourage imagination and then delve deeply into the equations to see how we can use our mathematical understanding to solve some of QM's problems this would in my view be a far better way of encouraging more physisists than turning off people who realize that there maths needs work and drop out cause they think they can't keep up, if the student who's maths needs work is excited about the implications behind the concepts he/she will be more likely to stay the distance, this approach may well ease the shortage of physisists and help to encourage people to think about physics as a career.

 

[ZapperZ]

Yes I am not arguing that you should forgo the maths simply that as Misogynistic Feminist said, you encourage some excitement and wonder in students before, bombarding them with maths, what I'm suggesting is that for the first 3 months of say a degree, they learn the quantum and classical applications of physics, and the application of this on the astronomical scale, doppler effects simple mathematics like parsec equations and photon energy math, relativity, special relativity, nuclear physics, stuff to show the vast application of physics, to encourage imagination and then delve deeply into the equations to see how we can use our mathematical understanding to solve some of QM's problems this would in my view be a far better way of encouraging more physisists than turning off people who realize that there maths needs work and drop out cause they think they can't keep up, if the student who's maths needs work is excited about the implications behind the concepts he/she will be more likely to stay the distance, this approach may well ease the shortage of physisists and help to encourage people to think about physics as a career.

There is a difference between "motivation" to learn a subject and "effective teaching and understanding" of the subject. A good instructor will combine the two. I was addressing the latter mainly because the impetus for motivation can come from a wide variety of external sources. A "conceptual understanding" of QM is a dicey matter in trying to first learn and understand it. More often than not, one resorts to analogy and primitive examples. I've seen way too many of these being misinterpreted or giving off the wrong impression.

Zz.

 

[slyboy]

Now, what does THAT have to do with what you just said? I'm trying to illustrate the fact that it is a distinct possibility that QM is describing something in which our currrent "language" or understanding has no ability to accurately convey!

There is a "language" that can convey the concepts accurately. It's called quantum logic.

I'm not saying that revising logic is necessarily my preferred approach to the foundations of QM, but logic is supposed to be the study of formalized languages. Therefore, if you believe the conceptual problems are due to our use of language then maybe you should be promoting quantum logic.

 

[ZapperZ]

There is a "language" that can convey the concepts accurately. It's called quantum logic.

I'm not saying that revising logic is necessarily my preferred approach to the foundations of QM, but logic is supposed to be the study of formalized languages. Therefore, if you believe the conceptual problems are due to our use of language then maybe you should be promoting quantum logic.

Er... mathematics IS a formalized language of logic. Furthermore, one needs to know the rules of "quantum logic" to be able to use it. As physicists, one can't just learn the rules out of nowhere without understanding QM. So it boils down to learning QM first, and we're back to square one.

Zz.

 

[godzilla7]

i happen to be one of the lucky few to who maths has always come quite easily 'tis a language I'm currently getting to grips with on my course, and I am finding that I can readily accept the strict logical progression of its rules, having said that, I think for some it can be a strugle it isn't my idea to promote physics degrees in a different way the idea has been around for at least 30 years, sjust the huge shortage of physisists has brought the issue to the fore gain; what have they done to change the subject in that time: very little, some of the posts above would suggest that the inherent fear of change in the world of maths is partly the problem, we have to know the maths to truly understand the concepts, ok fine, but what's wrong with reversing the order of learning, learn the concepts then delve into the maths behind them, I really don't see how this would be any different from doing the math then understanding the concepts, same time of study, the only differenece is an increase in students? Of course the maths heads, say no, we must spend 3 years doing nothing but hardcore maths until our ears bleed, explain to me why bearing in mind 2 years and 9 months of hardcore maths and a few months of introduction is all I am asking. The unviersity in which I'm studying already does exactly this in its foundation courses, this should start at A level, and proceed into the degree so that students feel motivated, how many students do you think have left a physics degree because they struggled with the maths at first;it's already difficult in the first year to find your feet at university, without being forced to keep up from the get go. I work in a medical physics dept, so I've spoken to many with a physics degree, and many seem to think it might be an idea, from clinical scientist to administrative mangers, you don't have to be a genius at maths to have a rewarding career in physics, spoken to many who struggled, why is it so hard for people to change there approach to physics, Einstein wasn't the greatest mathemetician of his day, just the greatest thinker. I think it's just the innate fear of trying something new, to alleviate a problem, when the old fashioned just seems so comfortable. I think the word knockheads comes to mind, anyone like to think outside the envelope perhaps, try something to assuage a problem, no perhaps not then

 

[godzilla7]

And s'all very well talking about teaching methods to motivate students, but when the course has a set progression, then you'll probably find having just the dry material to work with would make it difficult to motivate anyone.

 

[ZapperZ]

i happen to be one of the lucky few to who maths has always come quite easily 'tis a language I'm currently getting to grips with on my course, and I am finding that I can readily accept the strict logical progression of its rules, having said that, I think for some it can be a strugle it isn't my idea to promote physics degrees in a different way the idea has been around for at least 30 years, sjust the huge shortage of physisists has brought the issue to the fore gain; what have they done to change the subject in that time: very little, some of the posts above would suggest that the inherent fear of change in the world of maths is partly the problem, we have to know the maths to truly understand the concepts, ok fine, but what's wrong with reversing the order of learning, learn the concepts then delve into the maths behind them, I really don't see how this would be any different from doing the math then understanding the concepts, same time of study, the only differenece is an increase in students? Of course the maths heads, say no, we must spend 3 years doing nothing but hardcore maths until our ears bleed, explain to me why bearing in mind 2 years and 9 months of hardcore maths and a few months of introduction is all I am asking. The unviersity in which I'm studying already does exactly this in its foundation courses, this should start at A level, and proceed into the degree so that students feel motivated, how many students do you think have left a physics degree because they struggled with the maths at first;it's already difficult in the first year to find your feet at university, without being forced to keep up from the get go. I work in a medical physics dept, so I've spoken to many with a physics degree, and many seem to think it might be an idea, from clinical scientist to administrative mangers, you don't have to be a genius at maths to have a rewarding career in physics, spoken to many who struggled, why is it so hard for people to change there approach to physics, Einstein wasn't the greatest mathemetician of his day, just the greatest thinker. I think it's just the innate fear of trying something new, to alleviate a problem, when the old fashioned just seems so comfortable. I think the word knockheads comes to mind, anyone like to think outside the envelope perhaps, try something to assuage a problem, no perhaps not then

First of all, it was VERY difficult to read this. May I suggest you consider adding paragraphs to your posting to give it some structure?

Secondly, I did NOT advocate "..we must spend 3 years doing nothing but hardcore maths until our ears bleed.." You are confusing learning the formalism of QM with learning the language of QM. One can have the adequate skills to know the language of QM with a mere 5 or 6 courses in mathematics/mathematical physics at the undergraduate level. This is NOT "3 years of hardcore maths".

Thirdly, how do you "conceptualize" something in which there are no classical equivalent? Look at how many times we have to correct the impression that an electron "orbits" the nucleus in an atom. Now skip ahead and look at the "orbital" solutions to a hydrogenic atom and tell me those LOOK like "orbits". This is one clear example where "conceptualizing" does more harm than good.

Fourth: who said anything about being a "math genius"? I'm very good at mathematics, but I have no patience for mathematics in of itself. It is why I have continuously advocate physics students to get as much necessary mathematics as quickly as possible without having to go through all those mathematics classes. One does this via going through a mathematical physics course, or book, so that one is well-equipped to handle the formalism presented in classical mechanics, E&M, QM, etc. Experimentalists, especially, have very little patience and inclination to spend most of their undergraduate years taking that many mathematics classes.

You learn something via understanding. Only upon understanding, do you have an accurate, and adequate conceptualization of what it is. Till then, all you have is a superficial image of what you THINK it is.

Zz.

 

[godzilla7]

I think I did it all in one paragraph,cause there was no change of subject, so technicaly I didn't have new paragraphs, but point taken.

Anyway I have and understanding of the electron cloud produced by the hydrogen atoms, because, I have been shown computer representations of these and the photographs of the original experiments, I don't know the derivations of the eigen values behind this yet, but then when I do learn the equations, I'll have a moment of inspiration where I can say it's all clear now, I know little of the maths behind it, I can understand why an electron doesn't literally spin but has an expected range of values, by looking at a model of an electrons range of values. I think your creating problems where none exist, a good computer model well presented and with a good teacher can present the misconceptions of physics without complex maths; I understand that without care, students may be mislead, but I have learned the reality behind the myth cause I had good literature and good course material that pointed out the reality behind the maths. I'm nothing special but If I know about the concepts without maths, then why believe that other people won't get it to. bear in mind that I have no on site tutor to talk to face to face, just course material and contact numbers and emial.

Anyway the reality is, students in England aren't studying physics or are dropping out early from courses, because of the maths element; what do you suggest we do about this brain drain towards other subjects?

We need some ideas, not saying what I'm saying is necessarily the best way, but then neither is advocating the status quo, its not working what do we do about it?

 

[ZapperZ]

Anyway the reality is, students in England aren't studying physics or are dropping out early from courses, because of the maths element; what do you suggest we do about this brain drain towards other subjects?

We need some ideas, not saying what I'm saying is necessarily the best way, but then neither is advocating the status quo, its not working what do we do about it?

It is one thing to say that there is a drop in students majoring in physics. It is ANOTHER to BLAME it on the way it is taught. Some of the DRYEST lectures I've been in while in school was in an engineering mechanics class. Yet, you don't see people abandoning that field because of that!

Please don't get me started on the ineffectiveness of society and many in the physics profession of selling their profession. I had just come back from talking to a bunch of high school kids and trying to flush out of their mind that physics and physicists are either "string theory" or "particle physics" or "astronomy", or something esoteric of that nature that simply has no effect on their lives. How about promoting that field of study and its undenyable importance, not only in the advancement of knowledge, but what it has done and can do directly to people's lives? Is this such a novel concept to get more people to be interested in it?

I would also advice you to withold your claim that your current "conceptual" understanding of atomic orbitals based on some computer simulations or pictures is an accurate representation of what it really is as formulated within QM until you have fully seen it in detail. You will find that QM holds a lot more surprises than what you think.

Zz.

 

[godzilla7]

Sounds like what your doing is a valuable contribution to physics, I am attacking not physics itself but the idea that we can allow the decline of physics to continue, Where I live Portsmouth University has no physics department at all, it was closed five years ago because it wasn't cost effective. I hate to see closures of physics dept.

It's not necessarily the courses fault, after all given the choice of a good job regardless of the degree, would you chose physics or something supposedly less taxing like media studies, a lot of high payed jobs don't require any specific qualification just a degree level education, (interesting side note: back in the 90's many hundreds of physicists were poached by the financial markets) and so people do something that would be considered less difficult than the sciences, and physics is not the only science subject that's suffering chemistry is also I've heard.

It's not surprising that a lot of students consider physics to be of no practical use, for a long time after its inception much of quantum mechanics was just that, it's only now with nano-technology and quantum encoding and a vast array of avant garde technologies that it's really gained the practical momentum it deserves; students need re-educating, it's not a crime to say that teachers need re-educating to re-educate students, I'd be surprised if you yourself hadn't changed your approach over the years.

The media seems obsessed with strings and the quantum, little is mentioned about optics, classical physics, Nanotech and the myriad of other physics applications, so I guess the average person only sees the smallest theoretical parts of physics.

Starting at school it has been suggested - not by me I hasten to add but by academia(or at least part of it) - and then college level(16-18 year olds in England) physics courses need to start enthusing students with the concepts behind things not just the classical mathematics but at A level(these are college courses kind of specifically geared to prepare students for a degree in a subject/ say if you wanted to go into physics, you'd study maths:pure and applied, physics, maybe computer studies and perhaps chemistry and or something else similar, some of the brighter students do 5 A levels) they now study the quark model, why not introduce some of the reasoning behind this, hey even some of the less arduous maths, starting pushing the theoretical concepts I still think would be a good idea. It's not >I< that had highlighted the problems with physics in my country, it is other physicists who are saying the maths element is turning students off,snot solely to blame, never that simple, but it's an element that needs some thought.

Standing on the other side of the fence as a student It worries me that there is such little interest in the subject.

Just advocating that at degree level we spend a short while enthusing students, I guess this is not the way to go, after all the way it's taught now is obviously working

 

[selfAdjoint]

I personally am all for an early teaching of the reasoning, as opposed to the stamp collecting aspect that "teaching the quark model" or any other model so easily slides into. In the US bright high schools students take calculus; why shouldn't there be an intro physics theory course for them? First semester, relativity with rapidity and hyperbolic functions, solving sensible problems and classic puzzles, maybe doing the muon lifetime. Second semester one dimensional Schroedinger physics, working up to the square well.

Of course there are always the two constraints: money and teacher talent. Anything "highbrow" like this has to compete with "relevant" courses as politicians and parent groups define them. And sad to say, really talented teachers are few and far between.

 

[Mike2]

I personally am all for an early teaching of the reasoning, as opposed to the stamp collecting aspect that "teaching the quark model" or any other model so easily slides into. In the US bright high schools students take calculus; why shouldn't there be an intro physics theory course for them? First semester, relativity with rapidity and hyperbolic functions, solving sensible problems and classic puzzles, maybe doing the muon lifetime. Second semester one dimensional Schroedinger physics, working up to the square well.

Of course there are always the two constraints: money and teacher talent. Anything "highbrow" like this has to compete with "relevant" courses as politicians and parent groups define them. And sad to say, really talented teachers are few and far between.

So do a video series on DVD, what? Tests can be done on-line, what?

 

[selfAdjoint]

Mike, this is a great idea! I am not the man to do it, but some who post here could really make a public contribution! Might take a few videos with accompanying text, but as you say, tests of a kind can be done on line. This IMHO is the weak point of the online courses I have taken (Relativity, Strings 101, QFT 101, Quantum Physics 101); they used offline homework from the textbooks whereas simpler online exercises could have been worked up and provided an active feedback loop. Just excercises on understanding the concepts and manipulating the formalism until you get good enough (in the moderator's and your own opinion) and only then the harder type they put in graduate textbooks.

Somebody posted about the "click" when what you are laboriously trying to learn/do jells and suddenly it's like a different world. Bicycle riding or group theory or whatever. This experience, in the context of basic relativistic and quantum manipulations is what we should be trying to bring to young people. But it involves a LOT of work; those online excercises and tests have to be DESIGNED from scratch, not just copied from a book or pulled off the top of somebody's head.

 

[reilly]

There's a standard cliche that you don't really understand a subject until you have taught it. After teaching a year of graduate level QM, my "understanding of QM jumped big-time -- true also for mechanics, and E&M --, as did my appreciation for the complexities of teaching QM.

What's to understand? Do we really understand classical physics, or, perhaps, because we are so familiar with the ideas and techniques and successes, that we gloss over the problems -- why does Newton's 2nd Law apply to nature? I suggest that when we claim understanding of classical mechanics, we mean that we understand the implications of the basic equations of mechanics. During the time of the Greeks, the ideas of Newton would not have been understood at all.

As far as I'm concerned I understand QM in the sense that I'm familiar, from lot's of experience,.with many of the implications of QM -- atomic theory, superconductivity, nuclear physics, particle physics. My understanding is empirical and practical in nature, and does not deal with the "why does it work" issue, which is a basic question for classical as well as quantum theories.

Those elusive basics are no farther away in QM than they are in classical physics. Familiarity brings, well, more familiarity. Because of centuries of acclaim and success, Newton's laws are as familiar to us as is driving a car -- they are in our classical comfort zone.

QM is clearly here to stay, perhaps modified somewhat, and the myriad successes of QM just keep on coming. My bet is that in another generation or two, people will be puzzled by the don't/can't understand QM statements. To understand QM, you have to rid yourself of much of classical physics, and thus, with all due respect, those quoted (#54, Eye-in-the-Sky) Feynman, Gell-Mann, et al didn't do that.

Really, if you take QM in its standard every-day working-physicist form, what's to understand? The Schrodinger Eg. is just another partial differential equation. The absolute square of a solution is, according to Born, a probability density. You got your bound states, your states in the continuous spectra, scattering theory all of which have immediate physical interpretations based on mathematically similar classical problems. (There's a lot of highly technical mathematical tools that are essential to the mastery of the subject, like angular momentum theory.) We'll leave relativity for another day, and EPR and all that. Except to note that the controversy over the EPR-type experiments, does not seem to have hampered the progress of physics -- experimental and theoretical.

Why does QM work? Why are we stuck with probability? Why does mass generate gravitation? Why is math so powerful in science -- Wigner wrote about this. In physics, why does math work?

QM's whys are no worse than any other major scientific theories -- they are a bit outside our comfort zone. But that is sure to change -- everybody loves a winner, well arguably.



Regards,
Reilly Atkinson

 

[godzilla7]

I think this is true, as part of my course it is advised you discuss the subject with someone who doesn't know what it is your talking about, so that you can clarify your own ideas, I found it extremely useful to go through how I understood something to work with someone else.

I think difficult concepts like spin and colour charge and electron superposition can be expressed in simple diagrams and computer models, I have seen such models, as long as it's made clear that to truly understand what's going on to any thing approaching accuracy we need to look at the maths behind it, then students can get some feel for the processes, carefully showing that things are quite weird in the quantum world would not be impossible.

I think the quantum needs to be explained in non mathematical language at first, otherwise when you look at the maths your going in cold with no idea what to expect, going in with some ideas, however inacurrate or erroneous, only helps to strengthen our concepts when we say I have it so the Eigen value of psi or whatever is non deterministic in the range of. so the electron is in a superpositon we can pinpoint it's location but this will alter its speed and thus we can never truly know it's location. now If I use Bohmian Mechanics equations I can show etc. etc. we may not have a non mathematical language for QM but I don't think it does any harm to visualize our complex calculus in a form a non mathematician can grasp, may not be the whole picture, but if we make it clear it isn't there's no harm there.