What is the bare minimum necessary to "get" quantum mechanics?

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JC_Silver
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Sorry for any English mistakes, it's not my first language.

I'm building a guide in the style of "X for dummies" for QM. The idea here is to allow people from different areas of knowledge to be able to have a better grip on QM in both a mathematical stance and a desmystifying stance.
I was inspired to write this after seeing so many of my friends armed with PhDs in Biology having a hard time understanding physics concepts, even the ones related to their field such as the possible way birds see the Earth's magnect field, etc.

So I decided to write a QM guide that has enough information and math to allow someone with a PhD to follow the news and maybe even calculate a few things on their own while not being a 8 years endearvor where they basically need to get a new graduation.

So, what are the most important concepts to teach and what order should they be taught?

For example, I'm currently inclined to start by teaching hamiltonian mechanics, since that is not something you learn in my country's schools in any shape or form, while probably having to reinforce or even teach differential equations, since I'm not sure Biologists even learn differential equations.

Any insights or tips are welcome.
 
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  • #2
You can check the Griffiths on quantum mechanics it does a good job in keeping it as minimalistic as possible. Obvious ingredients are linear algebra, complex numbers and multivariable calculus. For the physics is mostly Hamiltonian mechanics, as you say, and electromagnetism.

However if I had to informally teach somebody quantum mechanics, I would start with wave mechanics in general. I think much of the misconceptions in quantum mechanics start because people want to try to talk about "wave-particle dualities" without any idea of what a wave is or how it behaves.
 
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  • #3
pines-demon said:
You can check the Griffiths on quantum mechanics it does a good job in keeping it as minimalistic as possible. Obvious ingredients are linear algebra, complex numbers and multivariable calculus. For the physics is mostly Hamiltonian mechanics, as you say, and electromagnetism.

However if I had to informally teach somebody quantum mechanics, I would start with wave mechanics in general. I think much of the misconceptions in quantum mechanics start because people want to try to talk about "wave-particle dualities" without any idea of what a wave is or how it behaves.
Thanks, I'll look into it!

Edit: Just opened the book it was exactly what I was looking for!
 
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  • #4
What is your background?
 
  • #5
gleem said:
What is your background?
I am a high school teacher and a librarian
 
  • #6
JC_Silver said:
I am a high school teacher and a librarian
I should have emphasized educational background.
 
  • #7
gleem said:
I should have emphasized educational background.
Sorry, I understood you but I am too used to things over here where saying you are a high school teacher = graduate, since anyone going beyond grad school won't accept such low paying job as a teacher. :P
 
  • #8
Are you a college graduate and in what major?
 
  • #9
gleem said:
Are you a college graduate and in what major?
Yes, and I guess if I had to translate it would be "physics teacher major"? We don't have majors and minors and google translate is trying to translate "licenciatura" to degree which is incorrect.

But I'm not sure where you are getting at.
 
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  • #10
JC_Silver said:
But I'm not sure where you are getting at.
You are neither a physicist nor a biologist. Can you write a book that will be useful to a biologist?
JC_Silver said:
For example, I'm currently inclined to start by teaching hamiltonian mechanics, since that is not something you learn in my country's schools in any shape or form, while probably having to reinforce or even teach differential equations, since I'm not sure Biologists even learn differential equations.
You are looking to undertake an ambitious project. Too much physics or too little biology and you lose the targeted reader. Biologists these days probably do take Calculus which may include an intro to diff eqs. But I do not think you want to get into the math details of QM let alone Hamiltonian mechanics. Do you know the biological effects of quantum mechanics? For starters, you could download a copy of "Life on the Edge - The Coming of Age of Quantum Biology" By Johnjoe McFadden and Jim Al-Khalili at https://www.pdfdrive.com/life-on-the-edge-the-coming-of-age-of-quantum-biology-d179012261.html

Perhaps writing an introduction to the aforementioned book to fill in those things that you think it does not cover well might be valuable. Good Luck.
 
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  • #11
gleem said:
You are neither a physicist nor a biologist. Can you write a book that will be useful to a biologist?
That sounded rude but I'll assume it's the language barrier causing a misunderstanding.
gleem said:
You are looking to undertake an ambitious project. Too much physics or too little biology and you lose the targeted reader. Biologists these days probably do take Calculus which may include an intro to diff eqs. But I do not think you want to get into the math details of QM let alone Hamiltonian mechanics. Do you know the biological effects of quantum mechanics? For starters, you could download a copy of "Life on the Edge - The Coming of Age of Quantum Biology" By Johnjoe McFadden and Jim Al-Khalili at https://www.pdfdrive.com/life-on-the-edge-the-coming-of-age-of-quantum-biology-d179012261.html

Perhaps writing an introduction to the aforementioned book to fill in those things that you think it does not cover well might be valuable. Good Luck.
As said in the post, the target readers are my friends (and my wife), I'm not writing a book here.
These people are building AI models to recognize different bird species by their sound and running statistics on R for breakfast, if I can understand Hamiltonian mechanics, so can they.

The only question I asked is how much fat I could trim down before QM becomes incomprehensible.
Eg. Is it necessary to talk about gravity to explain QM? No. Should I talk about String Theory? Obviously not either. Do I need to talk about complex numbers? Probably a good idea since we are going to use it a lot.
 
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  • #12
JC_Silver said:
Do I need to talk about complex numbers? Probably a good idea since we are going to use it a lot.
So what is your target audience going to do with your document? Hopefully to get some understanding of the role that QM plays in biological systems.

JC_Silver said:
That sounded rude but I'll assume it's the language barrier causing a misunderstanding.
I'm sorry you took it that way. I merely stated my opinion as I see it that you have not been fully schooled in either physics or biology. Writing a document relating the two subjects for persons who may not have an adequate background will be difficult. Including a formal presentation of QM including Hamiltonians and PDEs would only be appropriate for students of Quantum Biology for they would have been prepared. But for those students a standard QM course is appropriate.

Perhaps a survey of simple explanations of QM available on the web can give you a basis for your project.
 
  • #13
gleem said:
So what is your target audience going to do with your document? Hopefully to get some understanding of the role that QM plays in biological systems.


I'm sorry you took it that way. I merely stated my opinion as I see it that you have not been fully schooled in either physics or biology. Writing a document relating the two subjects for persons who may not have an adequate background will be difficult. Including a formal presentation of QM including Hamiltonians and PDEs would only be appropriate for students of Quantum Biology for they would have been prepared. But for those students a standard QM course is appropriate.

Perhaps a survey of simple explanations of QM available on the web can give you a basis for your project.
I have been schooled in physics, that's the part that sounded weird from your answer. How would I qualify for being a physics teacher if I hadn't?

My first answer to you was that I'm a teacher, looking for a way to simplify something to teach, and the answer I got was "you are not a physicist", so you can imagine it sounded a bit rude...
 
  • #14
JC_Silver said:
I have been schooled in physics, that's the part that sounded weird from your answer. How would I qualify for being a physics teacher if I hadn't?

My first answer to you was that I'm a teacher, looking for a way to simplify something to teach, and the answer I got was "you are not a physicist", so you can imagine it sounded a bit rude...
I know he wasn't wanting to be rude. I've read literally thousands of his posts here, and he is focused on doing a good job of being helpful. That is one of the requirements here for being awarded a Science Advisor badge.

I agree with the questions he's been asking. Your background when asking for help composing a simplified version of QM is important, along with your target audience:
JC_Silver said:
I am a high school teacher and a librarian
JC_Silver said:
Yes, and I guess if I had to translate it would be "physics teacher major"?
So here in the US, teaching high school science doesn't require an advanced degree in physics, so that raises a bit of a red flag. You've said that you have an MS degree, but in "teaching physics" which doesn't match up with an MS in Physics where you have a technical specialty and publish a Master's Thesis.

JC_Silver said:
As said in the post, the target readers are my friends (and my wife), I'm not writing a book here.
These people are building AI models to recognize different bird species by their sound and running statistics on R for breakfast, if I can understand Hamiltonian mechanics, so can they.
So the target audience really does not need to know any QM beyond the pop-science stuff that is published on YouTube, correct? Maybe just watch some of those videos to see which ones may be the most appropriate for your audience.

In past threads here at PF, we've been asked similar questions about how to present simplified versions of some very technical scientific subjects to targeted audiences, but that was usually by persons who were very much experts in the technical fields that they were asking for help in. There is an art to simplifying difficult subjects while still preserving technical rigor, but there are also some subjects where trying to dumb-down the concepts without the full mathematical treatment just does not work.
 
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  • #15
berkeman said:
I know he wasn't wanting to be rude. I've read literally thousands of his posts here, and he is focused on doing a good job of being helpful. That is one of the requirements here for being awarded a Science Advisor badge.

I agree with the questions he's been asking. Your background when asking for help composing a simplified version of QM is important, along with your target audience:


So here in the US, teaching high school science doesn't require an advanced degree in physics, so that raises a bit of a red flag. You've said that you have an MS degree, but in "teaching physics" which doesn't match up with an MS in Physics where you have a technical specialty and publish a Master's Thesis.

Just so I don't sound like a lunatic, where I'm from you don't choose which classes you are going to take as an undergrad, you have to choose right after high school if you want to take a non-teaching degree or a teaching degree and continue that path to the end.
Both degrees look the same except the teaching degree has one extra semester for pedagogy classes. And both can get you into research and both can go for masters and a PhD on any area of the field.
However, people with a non-teaching degree CANNOT teach at any school, a problem my wife went through, since even though she has a PhD and has been supervising masters and grad level students, she was not allowed to teach biology to teenagers until she took a teaching degree.
The common strategy is to go for a teaching degree and work for a high school while you do your masters and PhD without needing a scholarship nor grants.
So a non-teaching degree gets you a diploma a bit faster but you are not allowed inside a classroom, that's why I'm very carefull to specify that I do have a teaching degree and therefore, am not breaking the law by being a teacher.

As an off-topic comment, our conservative governor has been trying to side-step this by, for example, renaming 2nd year physics "Energy and conservation", since it's not a physics class, it's an "Energy and conservation" class, he can hire anyone to teach. This is of course not siting well with the teacher's union. (https://acervodigital.educacao.pr.g...&noattach=true&ref=55642&ext=pdf&k=0e26b39e7d if you want to check, "Energy and Astronomy is on page 499)

berkeman said:
So the target audience really does not need to know any QM beyond the pop-science stuff that is published on YouTube, correct? Maybe just watch some of those videos to see which ones may be the most appropriate for your audience.

In past threads here at PF, we've been asked similar questions about how to present simplified versions of some very technical scientific subjects to targeted audiences, but that was usually by persons who were very much experts in the technical fields that they were asking for help in. There is an art to simplifying difficult subjects while still preserving technical rigor, but there are also some subjects where trying to dumb-down the concepts without the full mathematical treatment just does not work.
I'll be honest, I haven't seen much pop-science stuff on Youtube that goes beyond "trust me bro" with clickbait headlines. One of my friends (the bird guy I commented) regularly talks about watching the latest PBS Spacetime episode but there are so many videos they make on topics which are... I don't know how to put it, but such as their "Quantum eraser" episode, you know?

I believe Griffith's book sugested by @pines-demon was what I was looking for already, and if I end up boring my friends to death by being unable to do this little project, that's fine, at least I put my teaching muscles to work on something more engaging than trying to make Newton's laws interesting for Gen Z.
 
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JC_Silver said:
I believe Griffith's book sugested by @pines-demon was what I was looking for already, and if I end up boring my friends to death by being unable to do this little project, that's fine, at least I put my teaching muscles to work on something more engaging than trying to make Newton's laws interesting for Gen Z.
Griffith's book is a popular undergraduate text. Studying the opening chapters of that book is equivalent to undertaking a full-on undergraduate course.

One alternative are the notes by James Cresser, available free online:

https://physics.mq.edu.au/~jcresser/Phys304/Handouts/QuantumPhysicsNotes.pdf

These contain more insight into the background and the necessity of QM. And, although they are effectively undergraduate notes, they may be more accessible to non-physics majors. These notes are full of insight into why QM is the way it is.

Most popular-science texts tend to emphasise the weirdness of QM and, perhaps unwittingly, have a strongly classical bias. They often over-emphasise, for example, Einstein's objections to QM. And, they often leave the reader with the sense that QM is a bit of a ugly duckling. Whereas, Cresser emphasises that classical physics cannot produce the complexities of chemistry and our universe.

This change of perspective can prove quite hard for the non-physics student. From seeing QM as the problem, to seeing classical physics as the problem!
 
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  • #18
PeroK said:
Griffith's book is a popular undergraduate text. Studying the opening chapters of that book is equivalent to undertaking a full-on undergraduate course.

One alternative are the notes by James Cresser, available free online:

https://physics.mq.edu.au/~jcresser/Phys304/Handouts/QuantumPhysicsNotes.pdf

These contain more insight into the background and the necessity of QM. And, although they are effectively undergraduate notes, they may be more accessible to non-physics majors. These notes are full of insight into why QM is the way it is.

Most popular-science texts tend to emphasise the weirdness of QM and, perhaps unwittingly, have a strongly classical bias. They often over-emphasise, for example, Einstein's objections to QM. And, they often leave the reader with the sense that QM is a bit of a ugly duckling. Whereas, Cresser emphasises that classical physics cannot produce the complexities of chemistry and our universe.

This change of perspective can prove quite hard for the non-physics student. From seeing QM as the problem, to seeing classical physics as the problem!
This is very interesting, I'll for sure check these notes after lunch, and your point on the focus on the "weirdness" of QM and the classical bias is one thing that has always bothered me on my undergrad classes. Some professors seemed to enjoy mystifying QM, one professor even told us to watch "The men who stared at goats" to get more insight into QM, which made me feel as if either I was dumb as a rock or the professor was insane.
 
  • #19
JC_Silver said:
which made me feel as if either I was dumb as a rock or the professor was insane.
The latter is more likely true although I have learned these are not mutually exclusive!
There is a very old joke about the tourist in New York City who asked the wino on the corner "how do I get to Carnegie Hall". He received the quite correct reply: "practice, man, practice"...
In that spirit I would advise you to "practice, man, practice". Griffiths is likely a good start. Add the Feynman Lecures for local color. Enjoy. Specific questions can be directed to Physics Forms.
 
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hutchphd said:
The latter is more likely true although I have learned these are not mutually exclusive!
There is a very old joke about the tourist in New York City who asked the wino on the corner "how do I get to Carnegie Hall". He received the quite correct reply: "practice, man, practice"...
In that spirit I would advise you to "practice, man, practice". Griffiths is likely a good start. Add the Feynman Lecures for local color. Enjoy. Specific questions can be directed to Physics Forms.
Feyman lectures box were the first books I bought as an undergrad, had to pull a whole month of pay to afford them, totally worth it tho.
 
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  • #21
JC_Silver said:
This is very interesting, I'll for sure check these notes after lunch, and your point on the focus on the "weirdness" of QM and the classical bias is one thing that has always bothered me on my undergrad classes. Some professors seemed to enjoy mystifying QM, one professor even told us to watch "The men who stared at goats" to get more insight into QM, which made me feel as if either I was dumb as a rock or the professor was insane.
Here's an example that is all over popular science sources. There is a classical prejudice that if a particle does not have a well-defined position, then it does not exist. And, it's the act of measurement of position that brings the particle into existence. That's not correct at all. The dynamic properties of a quantum particle are described by the wave-function, which evolves in time. If the particle did not exist, there would be no wavefunction to evolve. A position measurement results in the dynamic quantity of position being more tightly defined. The particle is localised. The particle exists (as far as that has a meaning in physics) all the time. In short, the difficulty is to reimagine a particle as something that exists in a state other than of well-defined position at all times. Instead of helping the student make that intellectual leap, many sources emphasise the classical prejudice, and encourage the student not even to try to reimagine things.

Even the great man himself, Albert Einstein, challenged Bohr over whether the Moon exists when we are not looking at it. That confuses the case of a single, elementary or microscopic particle with that of a macroscopic system of particles that are continually interacting within a larger environment. On the scale at which the Uncertainty Principle operates, the position of the Moon is not well-defined. But, that is such a tiny uncertainty (a tiny fraction of the width of an atom), that this uncertainty is not quantitatively incompatible with the Moon always being in the position we expect it to be.

And, of course, it takes a certain confidence on my part (as a humble amateur student of physics) to go against the great man and declare that (albeit 100 years later) I understand something that he either did not or chose not to.
 
  • #22
JC_Silver said:
Sorry for any English mistakes, it's not my first language.

I'm building a guide in the style of "X for dummies" for QM. The idea here is to allow people from different areas of knowledge to be able to have a better grip on QM in both a mathematical stance and a desmystifying stance.
I was inspired to write this after seeing so many of my friends armed with PhDs in Biology having a hard time understanding physics concepts, even the ones related to their field such as the possible way birds see the Earth's magnect field, etc.

So I decided to write a QM guide that has enough information and math to allow someone with a PhD to follow the news and maybe even calculate a few things on their own while not being a 8 years endearvor where they basically need to get a new graduation.

So, what are the most important concepts to teach and what order should they be taught?

For example, I'm currently inclined to start by teaching hamiltonian mechanics, since that is not something you learn in my country's schools in any shape or form, while probably having to reinforce or even teach differential equations, since I'm not sure Biologists even learn differential equations.

Any insights or tips are welcome.
I've been holding back on replying for a bit to first see what other people suggest; I'm replying now because I am a little confused on who your target audience for this is- it seems as though you want to reach biologists/physiologists, but even that is a bit vague. For example, people working on protein structure or folding should already be conversant in density functional theory.

So here's a zeroth-order suggestion: write something that explains photosynthesis. There's excellent source material (some early papers: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1751-1097.1982.tb02655.x, https://pubmed.ncbi.nlm.nih.gov/4333045/, https://pmc.ncbi.nlm.nih.gov/articles/PMC5264509/, etc.), bio folks are well acquainted with the phenomenon, and QM is required to really elucidate the mechanism.
 
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  • #23
I'd suggest the minimum necessary + .
 
  • #24
JC_Silver said:
My first answer to you was that I'm a teacher, looking for a way to simplify something to teach, and the answer I got was "you are not a physicist", so you can imagine it sounded a bit rude...
When I read your OP in the back of my mind, I felt that if one knows a subject well enough and knows his students, then he does not have to ask how to teach it. If you want to help with your friends' general understanding of QM there are numerous books including "Quantum Physics for Dummies" (an abridged copy is online) that are available that you could consult or recommend to your friends or help them understand their contents instead of writing your own. I still feel that a watered-down version of Griffin's QM is not appropriate for your audience.

JC_Silver said:
I was inspired to write this after seeing so many of my friends armed with PhDs in Biology having a hard time understanding physics concepts, even the ones related to their field such as the possible way birds see the Earth's magnect field, etc.
It would seem that you would want to show the relevance of QM and its concepts to Biology as a primary goal instead of trying to produce a general mathematical development of QM that probably is not easily accessible or useful to them. I still think a watered down version of Griffin's QM is not the way to go.

JC_Silver said:
I believe Griffith's book sugested by @pines-demon was what I was looking for already, and if I end up boring my friends to death by being unable to do this little project, that's fine, at least I put my teaching muscles to work on something more engaging than trying to make Newton's laws interesting for Gen Z.
ah, therein lies the rub.
 
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  • #25
gleem said:
When I read your OP in the back of my mind, I felt that if one knows a subject well enough and knows his students, then he does not have to ask how to teach it. If you want to help with your friends' general understanding of QM there are numerous books including "Quantum Physics for Dummies" (an abridged copy is online) that are available that you could consult or recommend to your friends or help them understand their contents instead of writing your own. I still feel that a watered-down version of Griffin's QM is not appropriate for your audience.
I'll check the QM for dummies, I confess I didn't even look for it because I've only ever seen "X for dummies" in movies and series as joke props to signal a character is stupid, but if it's a worth read I'll give it a chance. It's almost the same shock as when I found out "I can't believe it's not butter" was an actual product and not a gag from a sitcom.

About knowing your subject and your students, I tend to agree but I would still ask for advice knowing I'm not a perfect teacher and that there's always the chance someone tried something similar and might have a better idea or method I wouldn't have thought about before.
I'm very in favor of asking for second opinions whenever possible.
 
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  • #26
JC_Silver said:
I was inspired to write this after seeing so many of my friends armed with PhDs in Biology having a hard time understanding physics concepts, even the ones related to their field such as the possible way birds see the Earth's magnect field, etc.

I did not expect to be writing this post but upon reading the book on quantum biology that I suggested ("Life on the Edge - The Coming of Age of Quantum Biology" By Johnjoe McFadden and Jim Al-Khalili at https://www.pdfdrive.com/life-on-the-edge-the-coming-of-age-of-quantum-biology-d179012261.html) The authors spend time talking about the avian compass. Check it out.
 
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