Homework Help: Complex scalar field - Feynman integral

1. Dec 6, 2011

ryanwilk

1. The problem statement, all variables and given/known data

For a real scalar field $\phi$, the propagator is $\frac{i}{(k^2-m_\phi^2)}$.

If we instead assume a complex scalar field, $\phi = \frac{1}{\sqrt{2}} (\phi_1 + i \phi_2)$, where $\phi_1,\phi_2$ are real fields with masses $m_{\phi 1},m_{\phi 2}$, what is the propagator?

2. Relevant equations

N/A

3. The attempt at a solution

Is this true?: There's a 1/2 probability that the propagator has mass $\phi_1$, $\phi_2$ so the propagator should just be $\frac{1}{2} [ \frac{i}{(k^2-m_{\phi_1}^2)} + \frac{i}{(k^2-m_{\phi_2}^2)} ]$. But how does the 'i' change things?

Any help would be appreciated,

Thanks.

2. Dec 6, 2011

dextercioby

The Euler-Lagrange eqns (which typically determine the Feynman propagator) are completeley separated and identical with the original KG equation. So indeed the propagator will be written as a sum b/w a term with i and the other with i2.