Do I need E.M. theory for Quantum mechanics?

Click For Summary

Discussion Overview

The discussion centers around the relationship between Electromagnetic Theory (E.M.) and Quantum Mechanics (Q.M.), specifically addressing the necessity of understanding E.M. before studying Q.M. Participants explore the mathematical and physical prerequisites for Q.M., debating the importance of vector calculus and the role of E.M. in the context of Q.M. learning.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants suggest that a solid understanding of vector calculus is essential for studying Q.M., as it is integral to many physics courses, including classical mechanics and E.M.
  • Others argue that while E.M. is important, one can learn some aspects of Q.M. without a complete grasp of E.M., particularly in introductory contexts.
  • A participant expresses concern about their proficiency in vector calculus and questions how much E.M. knowledge is necessary for Q.M., indicating a desire to prioritize learning based on their strengths in mathematics.
  • Some participants emphasize the historical and conceptual significance of E.M., suggesting that it provides valuable insights that are beneficial for understanding Q.M.
  • There is a viewpoint that E.M. may be more challenging than Q.M. due to its rigorous problem sets, but it is still deemed necessary for a comprehensive understanding of Q.M.
  • A later reply reinforces that E.M. interactions are inherently part of quantum theory, suggesting that E.M. should not be viewed as a sidestep but rather as foundational.

Areas of Agreement / Disagreement

Participants generally disagree on the necessity of studying E.M. before Q.M., with some advocating for its importance while others believe that Q.M. can be approached without extensive E.M. knowledge. The discussion remains unresolved regarding the optimal order of study and the extent of E.M. required for Q.M.

Contextual Notes

Participants express varying levels of confidence in their mathematical skills, particularly in vector calculus, which may influence their perspectives on the prerequisites for Q.M. The discussion also reflects differing opinions on the complexity of E.M. compared to Q.M., indicating a lack of consensus on the relative difficulty of the subjects.

U.Renko
Messages
56
Reaction score
1
I don't plan to do neither very soon, I still need some pre-requisites.

But the thing is:
judging by what I see on books and people talking, E.M. depends heavily on vector calculus and Q.Mech depends heavily on group theory and linear algebra.

I suck at vector calculus and I'm okay with group theory and linear algebra.
So based on the MATHEMATICS alone, I'd skip E.M and go for Q.M

But about the PHYSICS, I just have no idea.
So I ask:
how much of E.M one must know in order to study Q.M.?
Is there vector calculus involved in Q.M. that I don't know of?


Keep in mind that there is still some time until there. So don't worry, I'll get the hang of vector calculus sooner or later
 
Physics news on Phys.org
If you don't want to work in multiple dimensions (3D/ vectors) then you are going to have trouble with hydrogen. There isn't a shortcut.
 
  • Like
Likes   Reactions: 1 person
If you want anything more than a pop-sci version of QM, I'd recommend you focus on learning vector calculus first, as it's essential in almost every physics course you'll take (CM, EM, and QM included).

You won't even see a large amount of group theory explicitly mentioned in undergraduate treatments of QM (if at all), though linear algebra will still be important.
 
  • Like
Likes   Reactions: 1 person
The notion of "sucking" at a particular branch of math is in 99.9% of cases delusional, ridiculous and harmful. You're basically accepting defeat. It's an excuse. If you "suck" at it, just work harder. You should never accept that you're naturally inept at something as important.
 
  • Like
Likes   Reactions: 1 person
I found my vector calculus course a lot easier than quantum mechanics! I vaguely remember the schaum book on vectors calculus being very good. I think it's a topic where doing a lot of problems really pays off. Can't remember the title of the book, it was so long ago (!), but I'm sure you can easily dig it out.
 
  • Like
Likes   Reactions: 1 person
Well, ok.
I understand that vector calculus is necessary in a quantum mechanics course.
And don't worry: I'll become good at it eventually.

But what I really want to know is how much of Eletromagnetic Theory is used on Quantum Mechanics.

Basically: Let's forget about the mathematical requirements. What are the physics requirements to study Q.M.?
 
You can learn *some* quantum mechanics without knowing electromagnetic theory, just as you can learn classical mechanics without knowing anything about electromagnetic theory.

For example, try reading the first six pages of Griffith's standard text on Quantum mechanics in Amazon look inside.

But all the serious textbooks quickly move on to assuming electromagnetic theory 'cause many of the most interesting/important situations assume an EM field. For instance, the hydrogen atom consists of two *charged* particles. Classical electromagnetic theory predicts the electron will spiral into the nucleus, emitting EM radiation as it goes. To understand why you need to understand a whole out of EM theory - right up to Maxwell's equations. Look at those first six pages of Griffiths again - could you understand them if you knew no classical mechanics? Answer: of course not! Same for any serious examples involving EM fields.

So read Griffiths "Introduction to Electrodynamics", or a similar textbook, before moving on to QM - note that chapter one is fifty page overview of vector analysis, which might be enough to get you up to speed.
 
  • Like
Likes   Reactions: 1 person
U.Renko said:
What are the physics requirements to study Q.M.?

I think you're looking at this the wrong way. EM is one of the most elegant, beautiful, and powerful theories of physics. Forget about QM. You're missing out on a lot of history and insightful physics by trying to sidestep EM. If anything, EM is harder to learn than QM because EM books will not be afraid to go all out and destroy your sanity when it comes to problem sets whereas every QM book I've seen has either ridiculously trivial problem sets or trivial but computationally tedious problem sets. There's a lot of tools in the "physicist's toolkit" that you will learn through a proper study of EM that you probably will have been expected to have honed by the time you attempt QM.
 
Last edited:
WannabeNewton said:
Forget about QM. You're missing out on a lot of history and insightful physics by trying to sidestep EM.

I'm not trying to sidestep it.
I was just thinking that MAYBE doing EM before QM would be counter-productive and/or counter-intuitive.I was also a little worried that it would be harder than Q.M..
Well. It probably is harder, but as mentioned in the thread, it is required anyway and thus not as counter-intuitive as I was thinking.

Anyways, Thanks for clearing that out!
 
  • #10
E&M before QM is not counter productive since e&m interactions are a part of quantum.
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
3
Views
2K
  • · Replies 60 ·
3
Replies
60
Views
7K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 5 ·
Replies
5
Views
937
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 6 ·
Replies
6
Views
3K