- #1
highflyyer
- 28
- 1
I am trying to understand the derivation of the Casimir energy from https://en.wikipedia.org/wiki/Casim...f_Casimir_effect_assuming_zeta-regularization.
At one point, the derivation writes the following:
The vacuum energy is then the sum over all possible excitation modes ##\omega_{n}##. Since the area of the plates is large, we may sum by integrating over two of the dimensions in ##k##-space. The assumption of periodic boundary conditions yields
$$\langle E \rangle=\frac{\hbar}{2} \cdot 2 \int \frac{A dk_x dk_y}{(2\pi)^2} \sum_{n=1}^\infty \omega_n$$
What does the size of the plates have to do with being able to integrate over two of the dimensions in ##k##-space? I don't quite see the connection.
Thank you so much in advance for any comments.
At one point, the derivation writes the following:
The vacuum energy is then the sum over all possible excitation modes ##\omega_{n}##. Since the area of the plates is large, we may sum by integrating over two of the dimensions in ##k##-space. The assumption of periodic boundary conditions yields
$$\langle E \rangle=\frac{\hbar}{2} \cdot 2 \int \frac{A dk_x dk_y}{(2\pi)^2} \sum_{n=1}^\infty \omega_n$$
What does the size of the plates have to do with being able to integrate over two of the dimensions in ##k##-space? I don't quite see the connection.
Thank you so much in advance for any comments.