The absurdity of US college textbooks

[5v333]

In particle physics interactions(some?) are discribed as exchanging of particles.
This violates one of the most fundamental laws in universe. Conservation of energy.

However this is possible for a short time period prior to the decay of an Exchange particle. This time window depends on guess what?

Heisenbergs principle of uncertainty!

After the summer comes
Relativistic physics
Statistical physics
Atomic/molecular physics
And a theoretical course in history, gender equality in science etc.

 

[user 37518]

After the summer comes
Relativistic physics
Statistical physics
Atomic/molecular physics

Very nice!! Sounds interesting, I remember now why I am an engineer and not a physicist. Don't get me wrong, I find it interesting, but I am really not that interested on going that deep into the rabbit hole.

And a theoretical course in history, gender equality in science etc.

 

[user 37518]

So back to the OP: for the fall semester I have to buy two books, one of them costs $248 new, the other a more "modest" $139 USD; that's $387 spent in two books, yeah....

Luckily this will be my last semester and then comes graduation.

 

[user 37518]

In particle physics interactions(some?) are discribed as exchanging of particles.
This violates one of the most fundamental laws in universe. Conservation of energy.

However this is possible for a short time period prior to the decay of an Exchange particle. This time window depends on guess what?

Heisenbergs principle of uncertainty!

After the summer comes
Relativistic physics
Statistical physics
Atomic/molecular physics
And a theoretical course in history, gender equality in science etc.

Hey 5v333, so what's next for this semester?

I am taking the last three courses, I was awarded advanced standing due to my previous Master's, so I basically got rid of 1 semester, hence, I will finish my degree in 1.5 years rather than 2. I will be taking some numerical stuff course, another regarding statistics/probability and my capstone course, in which I have to develop a project. I am still considering between developing a SRFT algorithm for impedance matching or some other thing involving optimization.

During the summer I took one of those "express" courses on predictive modelling, the best way I could describe it is machine learning or data science, very, very interesting, I learned to code in R.

What about you?

 

[5v333]

Same as before but rel mechanics comes after christmas. Instead we will have solid state physics this semester.
It will basically be material physics from molecules through gases and solids.
Loads of quantum physics, combinatorics and distributions.

We are going to visit Cern aswell!!!!

 

[user 37518]

Same as before but rel mechanics comes after christmas. Instead we will have solid state physics this semester.
It will basically be material physics from molecules through gases and solids.
Loads of quantum physics, combinatorics and distributions.

We are going to visit Cern aswell!!!!

Wow! So you are a going from Sweden to Switzerland as a group? That sounds amazing. Also, when you say solid state physics, does that involve semiconductor physics? I've take several courses in semiconductor physics, and, even though the theory definitely works, I still think it is a fantasy. The whole idea of the Schrödinger's wave function solution being the probability density function used to compute the probabilities of finding a particle, or the energy band theory, etc.... seems to me a good idea that somehow works, but that doesn't really explain the truth of what is happening.

There is a lot of "fudging" and patches going on with the theory, I remember when I used to listen to professors explain all this theory, they would beautifully derive all the equations and then point out that when measured experimentally the results didn't match the results of the equations, in fact they differed by a large amount, and they just do stuff like "well, we added this empirical constant to the equation which takes into account unknown second-order effects"; that to me just sounds like "the theory really doesn't work but we insist on making it work by adding mathematically unjustified terms into the equation that gives us the results we want." For instance the whole concept of the "effective mass of the electron" is an example of this and a joke to me, That sounds like something one of my students would do when he can't solve a problem.

When I teach semiconductor physics concepts to my students I always add a disclaimer saying that I don't believe all this crap hahaha sorry, maybe that is why I am an engineer and not a physicist

 

[5v333]

Yes we are prob about 20 physics student and a couple of students who are becoming teachers for high school education.

Here is the syllabus for the course.
https://kursplaner.gu.se/pdf/kurs/en/FYP330
This is a little on how i understand quantum physics.

There are still stuff in quantum physics that has not been explained. For ex, what the hell is spin?

You can see shrödingers equation and the probobility made from the innerproduct of states in a hillbert room as plain computational theory if you want.
It is among the most exact tools we have despite it being nothing else than probability.

Quantum physics is quite broad. Firstly it is about unique states in nature such as the unique spectrum of light emitted from atoms/molecules which tells us about the uniqe energy levels every atom can have.
Secondly it is about the smallest magnitude of every degrees of freedom in an object which can shift as non continous eigen values.
Using theese real observables together in hillbert rooms and with schrödinger we can predict amazing stuff to a degree that is remarkable.

However working with stuff that are so small, moving so fast and are very sensitive introduces questions of what a human can register with the best of measuring equipment without disturbing the setup.
This is what hesinberg was on about.
Its like asking what is going to happen in the future. Nobody can say for sure.
Or my own example: what is the true setting of a camera in order to capture the truthfull image of a moving object? There is no such setting right?

I have not had any studies on pertubation theory yet.
Which i guess is needed to get better real life results.
Predicting what 1 gazilion particles are going to do when reacting with each other at speeds over 500m/s is impossible.

 

[user 37518]

Yes we are prob about 20 physics student and a couple of students who are becoming teachers for high school education.

Here is the syllabus for the course.
https://kursplaner.gu.se/pdf/kurs/en/FYP330
This is a little on how i understand quantum physics.

There are still stuff in quantum physics that has not been explained. For ex, what the hell is spin?

You can see shrödingers equation and the probobility made from the innerproduct of states in a hillbert room as plain computational theory if you want.
It is among the most exact tools we have despite it being nothing else than probability.

Quantum physics is quite broad. Firstly it is about unique states in nature such as the unique spectrum of light emitted from atoms/molecules which tells us about the uniqe energy levels every atom can have.
Secondly it is about the smallest magnitude of every degrees of freedom in an object which can shift as non continous eigen values.
Using theese real observables together in hillbert rooms and with schrödinger we can predict amazing stuff to a degree that is remarkable.

However working with stuff that are so small, moving so fast and are very sensitive introduces questions of what a human can register with the best of measuring equipment without disturbing the setup.
This is what hesinberg was on about.
Its like asking what is going to happen in the future. Nobody can say for sure.
Or my own example: what is the true setting of a camera in order to capture the truthfull image of a moving object? There is no such setting right?

I have not had any studies on pertubation theory yet.
Which i guess is needed to get better real life results.
Predicting what 1 gazilion particles are going to do when reacting with each other at speeds over 500m/s is impossible.

Spin is a made up fantasy in order not to discard Pauli's exclusion principle, simple as that, you can either say that Pauli's exclusion principle was wrong, or you can invent the idea or analogy of electrons spinning to make sense of it. Sorry, quantum theory is a patched theory to make things agree with the real world. In terms of semiconductor physics, Quantum Theory as taught is not really used in the real world, everyone uses some type of behavioral modelling, which consists of taking measurements and using some fancy curve fitting, that is basically it; it is not much different from trial and error.

 

[5v333]

Spin is real.
Look up the Stern-Gerlach experiment or quantum computers.
Everything we know is patched up things to describe reality in some sence.

 

[user 37518]

Spin is real.
Look up the Stern-Gerlach experiment or quantum computers.
Everything we know is patched up things to describe reality in some sence.

Spin is a fantasy. Yes there is something that can be related to spin, there is no doubt about it, but it is still a fantasy, the concept that is.

I dont think Maxwells equations are a patched up theory, forget about relativistic effect for a second, Maxwell's equations work like a charm, you can input a structure into a FEM solver and it gives you almost the exact same thing. And there are not (at least not that many) fudge factors to force the equations to agree with reality.

 

[5v333]

It is the same with maxwell in my view. Yes it is beutyfull but that doesnt mean anything in science...

 

[user 37518]

It is the same with maxwell in my view. Yes it is beutyfull but that doesnt mean anything in science...

It is not the same fudging in my opinion, Quantum is a theory patched up all over the place, Maxwell works as is, I can attest that FEM gives very, very precise results; I can't say the same about Quantum theory, specifically speaking when applied to semiconductors.

 

[5v333]

Maxwell cant explain what induction is, just how to do some calculations where it is involved.
Im not even sure if anybody can explain what a field is. It is just a patched up theory as you say but a theory that follows some theorems and can be proved in many ways. Just like in quantum theory.

I think it is like you said about engineers and physicians. We are interested in things on different levels.

But it is also worth noting that quantum and relativistic theory is just about 100y old. While most things in classical physics goes back about 400y's.
Some things are impossible to discover because, as my friend says, it would take a particle accelerator that goeas al the way to the moon and back. Sounds like heisenberg actually.

 

[user 37518]

Maxwell cant explain what induction is, just how to do some calculations where it is involved.
Im not even sure if anybody can explain what a field is. It is just a patched up theory as you say but a theory that follows some theorems and can be proved in many ways. Just like in quantum theory.

I think it is like you said about engineers and physicians. We are interested in things on different levels.

But it is also worth noting that quantum and relativistic theory is just about 100y old. While most things in classical physics goes back about 400y's.
Some things are impossible to discover because, as my friend says, it would take a particle accelerator that goeas al the way to the moon and back. Sounds like heisenberg actually.

Well, nothing in science can explain what anything is at the fundamental level, like gravity, or if you even go further, nothing in science can say why 1 is 1, that is in the realm of philosophy, but that is not my point. My point is that Maxwell equations work perfectly well, theory matches reality, not so with Quantum Mechanics, you get some equation for a semiconductor, and reality differs by several orders of magnitude from the results of the equation, then they add an "empirical constant" and suddenly the theory matches reality. That is my point. It is an extremely patched theory. And just to be clear, I am talking here about QM in the context of semiconductor physics.

I could never be a physicists since it involves "abstract reality", for instance, I love pure mathematics, but when I am doing pure math I know I am in an abstract world, but with physics it feels like a merge between abstraction and reality, I don't like it. Also, I care about how to compute the inductance of something, but I really don't care what exactly is induction. For example, long time ago I stopped caring about what goes on inside the wires of equipment, yes I use the good old circuit laws, but I no longer like to either think of ball bearings traveling inside a tube or "clouds of probabilities" as a physicist might say; I prefer to think about waves of whatever there is surrounding the wires (I am referring to the E/D and H/B fields here) or leaving the wires, I can picture waves, and a wave vision of electricity is very close to reality, but I could care less about what those fields are made of, if that makes any sense. Ok, yes, I am an engineer, sorry for the rant.

By the way, you should see how us engineers design stuff at the professional level in stuff like high-frequency amplifiers, since we know shit about what is going on with the transistors (physicists don't know either), most people rely on behavioral modeling of the transistors, which is a fancy word for saying "measure data and fit a curve", and "numerical optimization" for the matching networks, which is a very sophisticated way of saying trial an error, haha maaan, to think that I went through 2 masters and 1 phd to end up doing the proverbial "throwing a stone at something and see if I get the results I want". Of course, there is a process to all this, but we are just doing the same thing cavemen did, but with a bit more knowledge and a lot more arrogance....

 

[5v333]

You reason in a loop like way with lots of contradictions and i think its time to stop for now so that we dont end up like most threads in the brewery.

 

[user 37518]

You reason in a loop like way with lots of contradictions and i think its time to stop for now so that we dont end up like most threads in the brewery.

I wasn't trying to create an argument, it was meant as friendly conversation. I was mocking engineers, but perhaps you felt I was attacking physicists. In any case, it wasn't my intention. Why would you say I reason in a "loop way" with lots of contradictions, I don't know, what is "loopy" about my reasoning? I thought we were just chatting and having a light conversation; I even mocked my own job.

I don't know exactly what bothered you. But ok, if you want to stop because you feel like we will end up like in the brewery because we are discussing QM or because I jokingly said that we engineers design stuff by trial and error, then, ok.

 

[5v333]

Sorry, I didnt see the jokes about Qphysics or maxwell.
Have a nice evening!

 

[user 37518]

Sorry, I didnt see the jokes about Qphysics or maxwell.
Have a nice evening!

To be fair, my jokes weren't that good either. Good day to you too.