Recent content by cello

Could you explain in more detail why: 1. DR only feels the logarithmic divergence. 2. only log divergences tell us something interesting. Thank you.

The reason we call the Higgs God particle is that it's everywhere, but has not been experimentally found yet, just like the status of God. The Higgs is not responsible for the majority of the mass of the universe. Even if quarks are massless, we still get massive protons, neutrons and etc...

Yes, you can always solve it, at least in a finite domain. Essentially this is because we are dealing with a set of ordinary first-order equations, for which the existence and uniqueness of the solution was established long ago. Weinberg mentioned this fact in his second volume of QFT textbook...

Can electron self energy diagram contribute to the vacuum polarization? Or is the question meaningful? What's the exact meaning of vacuum polarization? Does it necessarily involve some charged particle? For example, for the ordinary phi^4 theory, can I identify any diagram that can be called...

In any representation, the chiral basis is defined as the eigenvector of the projection operator. So it won't always be like (1,0).

It's just that in other representations the left-handed and right-handed spinors are mixed. It's super clear if you use the two-component notation. For references you can read Srednicki's QFT book.

I'm sorry but I don't get it. What do you mean by breaking phi up into a classical and quantum part? What kind of diagrams do you relate to the vev? Can you explain it in more detail? Thank you, fzero.

For example, in Srednicki's QFT book, he said: "because \langle\bar{\psi}\psi\rangle vanishes at tree level, perturbative corrections then also vanish, because of the chiral flavor symmetry of the lagrangian. Thus the value of vev is not accessible in perturbation theory." I don't understand...

This is not the real reason why the spins are the same. The spin, or any other quantum numbers of the antiparticle has to be the same with that of the particle, in order for them to be able to establish Lorentz invariance in the presence of conserved charges.