Hi,(adsbygoogle = window.adsbygoogle || []).push({});

I have a question about a statement I've seen in many a Quantum Field Theory book (e.g. Zee). They say that the general form of the Lagrangian density for a scalar field, once two conditions are imposed:

(1) Lorentz invariance, and

(2) At most two time derivatives,

is:

L = 1/2(d\phi)^2 - V(\phi)

where V(\phi) is a polynomial in \phi.

Why is this? I can understand how the conditions restrict the kinetic energy term to being what it is, but I don't understand why V has to be _polynomial_ in \phi.

**Physics Forums - The Fusion of Science and Community**

# The scalar field lagrangian

Know someone interested in this topic? Share a link to this question via email,
Google+,
Twitter, or
Facebook

- Similar discussions for: The scalar field lagrangian

Loading...

**Physics Forums - The Fusion of Science and Community**