Recent content by simic4

i say take qft from your physics department. then read zwiebach and polchinski simultaneously. after learning some qft many things become accessible.

Quote: It is also not known for certain that the gluon is actually massless, it is only supposed; all that is certain from measurement is that if it is not zero then its mass must be very small.well, interesting question. There exists a gluon field (analogous to the photon field),, unlike the...

Ah indeed,, I think I have it ( all these statements are in conformal gauge): First off, one should check BRST invariance of the "other" action (the action in 4.2.3,, the one before one integrates out B), this is obviously the more correct way to go: then the only place one must use the...

Hi, I am confused about the following, I was hoping someone could help: The context: Polchinski Ch. 4.2, specifically equations 4.3.1a-c I am verifying the BRST invariance of the bosonic string action (after one has integrated out B, and the weyl ghost),, I notice that one must use the...

hey well, thanks for all the replies. there are some useful refs there.

Since there seems to be no replies,, perhaps i can modify my question.. for those of you who have studied supersymmetry, or supergravity, how did you learn it? what did you find worked and what didnt. what is your story.. :) thanks!

All frequencies o light are emitted at once with a certain distribution curve, the black body curve. taht is certain frequencies are favored over others. for example your yellow hot material will emitt quanta highly peaked around the yellow light frequency. The peak frequency, yellow inn the...

haha yeah i figured..

hey tom don't sweat. the patter as one learns physics is: at first feeling you know something, then realizing you dont,,then this leads to deeper understadning till you think you know something,,,then you again realize you dont,,,and each cycle leads to a deeper understanding. perhaps you...

Just a comment on CarlB's proof. There is a much easier and more general way to prove that a photon cannot decay into electron anti electron pair. Let P be the fourmomentum of the photon. let P1 and P2 be the 4momenta of the resulting electron and anti electron respectively. the photon...

you can then verify that this IS a charge operator by considering a any definite particle state and noticing that it is an eigenstate of Q with eigenvalue of the form N-M (particles - antiparticles). The second thing you should check is the Q and H commute. You also might want to check that Q...

your expression for Q is not correct, since its not hermitian. you need to change the ordering of the pi and phi in one of your terms. then just plug in the quatnum expression of the phi and pi (in terms of creation operators) into that expression.

Hi, I am interested in teaching myself supersymmetry and supergravity. I have a decent qft background. I know of several good online notes,, but what I really need is a source of good problems. Anybody know where I can find such a source? Does the Wess and Bagger book have good problems...

Hey thanks a million. I forgot to split up the log, completely missed it :). sim.

Hi, This is regarding showing, in ch.7, around p.220, that the Pauli Vilars regularization technique is consistent with the ward takahashi identity. I cannot get the following to work: I add eq. 7.31 to eq. 7.32 and do not get zero. I get alpha over 4 pi. (I am left with integral ( 1...