Qft Definition and 956 Threads

Hello everyone, I am now learning QFT, this theory is really abstract and daunting. I can't understand the concept of vector field. What is vector field at last? why there are four polarization vectors? I feel that the whole theory is somewhat lack of reasoning, the postulates and assumptions...

What is quantum field theory and why was it developed? What is its relation to quantum mechanics?

Hi. I am new to this discussion group, so forgive me if this is not the appropriate forum for this question. A friend of mine and I are going through the first volume of Weinberg's QFT trilogy. My question regards the first problem at the end of chapter two. I think I completely understand the...

In critical phenomena, we can enlarge the block size(momenta fluctuation) by Kadanoff transformation, say k \rightarrow bk (b<=1) , and scale the new Hamiltonian by k' = k/b, x'=bx to recover to the original block size. In QFT, similarly integrating out the high momenta produces the effective...

I am interested in the input from the physics community on quantum field theory. If each particle has an associated field of which they are manisfestations what causes a particle to arise from a field?

Jeff mentioned he thought a thread on this might be good, and I decided to start it here so the board wouldn't be entirely blue sky. I'll start with a question raised by Patrick van Esch on s.p.r. In the Peskin and Schroeder textbook, they develop the expansion of the wave &phi; in the free...