I What is the relation between the Dirac equation and QED?

[thaiqi]

Hello, everyone.
Need I understand Dirac equation if I plan to learn QED?

 

[vanhees71]

Yes, but you can (and in my opinion should) start right away with the field-theoretical formulation. There's no merit to learn the awfully complicated formulation of QED in terms of Dirac's "hole theory", which is mathematically equivalent to modern QED but flawed in its conception. You start as if relativistic "quantum mechanics" would make sense only to find out that it doesn't, because in the relativistic regime of collisions the particle number is not conserved but particles can be destroyed and created in accordance with the conservation laws (energy, momentum, angular momentum, various charges). That's why the natural way to describe relativistic quantum theory is quantum field theory.

My favorite introductory textbook is

M. D. Schwartz, Quantum field theory and the Standard
Model, Cambridge University Press, Cambridge, New York
(2014).

 

[thaiqi]

Yes, but you can (and in my opinion should) start right away with the field-theoretical formulation. There's no merit to learn the awfully complicated formulation of QED in terms of Dirac's "hole theory", which is mathematically equivalent to modern QED but flawed in its conception. You start as if relativistic "quantum mechanics" would make sense only to find out that it doesn't, because in the relativistic regime of collisions the particle number is not conserved but particles can be destroyed and created in accordance with the conservation laws (energy, momentum, angular momentum, various charges). That's why the natural way to describe relativistic quantum theory is quantum field theory.

My favorite introductory textbook is

M. D. Schwartz, Quantum field theory and the Standard
Model, Cambridge University Press, Cambridge, New York
(2014).

Thanks. I have Cohen's Photons and Atoms at hand.
Are there any suggestions for how to learn Dirac's equation?

 

[dextercioby]

Thanks. I have Cohen's Photons and Atoms at hand.
Are there any suggestions for how to learn Dirac's equation?

Albert Messiah's old book on Quantum Mechanics is my favorite.

 

[glschmitt]

Yes, but you can (and in my opinion should) start right away with the field-theoretical formulation. There's no merit to learn the awfully complicated formulation of QED in terms of Dirac's "hole theory", which is mathematically equivalent to modern QED but flawed in its conception. You start as if relativistic "quantum mechanics" would make sense only to find out that it doesn't, because in the relativistic regime of collisions the particle number is not conserved but particles can be destroyed and created in accordance with the conservation laws (energy, momentum, angular momentum, various charges). That's why the natural way to describe relativistic quantum theory is quantum field theory.

My favorite introductory textbook is

M. D. Schwartz, Quantum field theory and the Standard
Model, Cambridge University Press, Cambridge, New York
(2014).

Is group theory the best viable option to advance modern physics?

 

[PeterDonis]

Is group theory the best viable option to advance modern physics?

This question is not answerable. People can of course give their opinions, but they're just that: opinions.

 

[glschmitt]

Yes, I agree. Group Theory is vital for advancement of modern theory.

 

[PeterDonis]

Yes, I agree. Group Theory is vital for advancement of modern theory.

You're not agreeing with me. You're just illustrating what I said: that the question is unanswerable. Your statement is just your opinion. That's not an answer; this is a physics forum, not a philosophy forum.