Recent content by SeySchW

Ok this makes sense. But then \Psi_{\alpha}^{\pm} is not a direct product state of one particle states otherwise it would transform like (3.1.1). How can we then define something like the index \alpha for \Psi_{\alpha}^{\pm} ? Beside: Where can I read more about this? I am completely...

Thank you for the answer, I'm not quite sure, if I understand this argument. So I will rephrase it. In a theory with no interactions we expect that the energy of a multiparticle state is the sum of the single energies. Whereas in an interacting theory this should be different. But I don't...

Hi, a few lines below equation (3.1.5) Weinberg writes: "The transformation rule (3.1.1) is only possible for particles that for one reason or another are not interacting." I thought a lot about it, but don't see any possible reason. Can you help please? After a few lines he defines...