  In this article, we follow the framework given in the article {\it Physica
A}, \textbf{158}, pg 58-63 (1989) by R. Laflamme to derive the thermofield
double state for a causal diamond using the Euclidean path integral formalism,
and subsequently derive the causal diamond temperature. The interpretation of
the physical and fictitious system in the thermofield double state arises
naturally from the boundary conditions of the fields defined on the Euclidean
sections of the cylindrical background geometry $S^{1}_{\beta}\times
\mathbb{R}$, where $\beta$ defines the periodicity of the Euclidean time
coordinate and $S^{1}_{\beta}$ is a circumference of length $\beta$. The
temperature detected by a static diamond observer at $x=0$ matches with the
thermofield double temperature derived via this path integral procedure.
