A. Zee, Quantum Field Theory in a Nutshell · Problem II.2.2

Field Theory Redux

Physics — QFT

Problem

Quantize the Dirac field in a box of volume of

V

and show that the vacuum energy

E_0

is indeed proportional to

V

. [Hint: The integral over momentum

\int d^3p

is replaced by a sum over discrete values of the momentum.]