Recent content by Tulzz

Hi!, I am studying for an introductory course in QED and Feynman Diagrams. Everything we see is like a first order approach and I am having some trouble understanding antiparticles in Feynman Diagrams: Why is it that we put an antiparticle that is leaving as if it is entering the interaction...

I know nothing about quantum field theory. For know I´ll accept that Dirac´s single particle descrption is 'wrong', at least to treat collisions, and that the'going backwards in time' interpretation its just a way of solving this inconsistency. The Lagrangian approach has more to do with...

So, for the sake of physical coherence, he is forcing E<0 solutions to go back in time (t→-t) , which is the same as saying: Its a E>0 solution going foward in time??

Hi, I don't understand the F-S interpretation of the E<0 energys of the Dirac Equation. I´m mainly reading about this in Francis Halzen´s book: Quarks and Leptons sec. 3.5. The book states: And then says: e^{-i(-E)(-t)} = e^{-iEt} Is he referring to the operator that evolves H eigenstates in...

Thanks a lot! I have one final questión: if I am studying the damped oscilator dynamics, do i still have to use the effective mass correction??

I guess i didn't express myself well. I know I have to use an effective mass when measuring K using a dynamic measurement technique. I don't fully understand the mass correction in the static case and why is it springmass/2 instead of springmass/3 as in the dynamic case. Another question i have...

I've been reading about this but I couldn't find a conclusive answer. I have to measure the spring constant (k) using a vertical spring-mass (M) configuration and using two different methods: - static method: I calculate elongation vs weight and find a linear fit of the data (the slope is K) -...