Michaelmas Term, 2006 and 2007
Preprint typeset in JHEP style - HYPER VERSION
Quantum Field Theory
University of Cambridge Part III Mathematical Tripos
Dr David Tong
Department of Applied Mathematics and Theoretical Physics,
Centre for Mathematical Scienc

6. Quantum Electrodynamics
In this section we nally get to quantum electrodynamics (QED), the theory of light
interacting with charged matter. Our path to quantization will be as before: we start
with the free theory of the electromagnetic eld and see how

Michaelmas Term, 2006 and 2007
Preprint typeset in JHEP style - HYPER VERSION
Quantum Field Theory
University of Cambridge Part III Mathematical Tripos
Dr David Tong
Department of Applied Mathematics and Theoretical Physics,
Centre for Mathematical Scienc

Quantum Field Theory: Example Sheet 3
Dr David Tong, October 2006
1. The Weyl representation of the Cliord algebra is given by,
0 =
01
10
i =
,
0 i
i 0
(1)
Show that these indeed satisfy cfw_ , = 2 , where 1 comes with an implicit 4 4
unit matrix. Find

4. The Dirac Equation
A great deal more was hidden in the Dirac equation than the author had
expected when he wrote it down in 1928. Dirac himself remarked in one of
his talks that his equation was more intelligent than its author. It should
be added, how

Quantum Field Theory: Example Sheet 1
Dr David Tong, October 2007
1. A string of length a, mass per unit length and under tension T is xed at
each end. The Lagrangian governing the time evolution of the transverse displacement
y (x, t) is
a
L=
0
2
y
t
dx

Part I
Feynman Diagrams
and
Quantum Electrodynamics
Chapter 1
Invitation: Pair Production
in e+e; Annihilation
The main purpose of Part I of this book is to develop the basic calculational
method of quantum eld theory, the formalism of Feynman diagrams. W