Lecture 6 - Poincaré invariance and Klein-Gordon field

Question 1

What type of angular momentum do scalar fields hold?

Answer 1

Orbital, but no spin

Question 2

Klein-Gordon equation describes particle with what spin?

Answer 2

spin-0 (pions and K-mesons)

Question 3

How is the shift in spacetime coordinates defined?

Answer 3

delta x_alpha = delta_alpha + epsilon_{alpha beta}x^beta

Question 4

What is the condition for a pure translation?

Answer 4

epsilon_{mu nu} = 0

Question 5

How is theta^i defined?

Answer 5

as 1/2*epsilon^{ijk}epsilon_{jk}