QFT 2 - Homework 1 Solution
January 30, 2014
1
To solve this problem, we need to calculate the propagator. We do this by rst calculating the
classical action. The classical path is:
xcl (t) = A cos ! t + B sin ! t
with the boundary conditions xcl (0) = x0
QFT 2 - Homework 3 Solution
March 3, 2014
1
This is outlined in Peskin section 10.1.
To show that the amplitude for the four point diagram given by
k1
k3
k2
k4
is proportional to the four external momenta cfw_ki , and hence eectively has a supercial degre
QFT 2 - Homework 1 Solution
February 13, 2014
1
1.1
We must assume that the derivative takes the form:
D=
ai
i
i
Then we see that we must have that, for some Grassmann variable i , we have
P (D (i ) = P (ai ) = ai = D (P (i )
Now we apply the same idea to
Physics 444
1
Lecture 1
Winter 2014
Recap of scalar, spinor and vector elds
From last quarter, recall that we have constructed scalar, spinor and vector elds. To avoid complications
associated with gauge elds, consider rst the case of massive vector elds.
Physics 444
Lecture 8
Winter 2014
Renormalization: operator renormalization and log summation
In practical applications, we often wish to perform perturbation theory for a process occuring at a low scale (),
using a theory dened at a high scale ( ). Provi
Physics 444
Lecture 7
Winter 2014
Renormalization: integrating out oshell modes
1
Integrating over a momentum shell
Consider a scalar (for simplicity) eld theory regulated by a cuto |kE | in Euclidean momentum space.
Taking t0 = it0 we have
E
()
dd x
iS S