- #1
etotheipi
I don't really know what I'm doing, I'd appreciate some nudges in the right direction. We defined ##\mathcal{S}## as the space of complex solutions to the Klein-Gordon equation, and for any ##\alpha, \beta \in \mathcal{S}## that ##(\alpha, \beta) =-\int_{\Sigma_0} d^3 x \sqrt{h} n_a j^a(\alpha, \beta)## where ##j(\alpha, \beta) = -i(\bar{\alpha} d\beta - \beta d\bar{\alpha})##. The exercise is to show that ##a_i' = \sum_j (\bar{A}_{ij} a_j - \bar{B}_{ij} a_j^{\dagger} )##, where the ##a_i## and ##a_i'## are the annihilation operators on ##\mathcal{S}_p## and ##\mathcal{S}_p'## respectively. So write ##a_i' = (\psi_i' , \Phi)## then\begin{align*}
a_i' &= \int_{\Sigma_0} d^3 x \sqrt{h} n^a j_a(\psi_i', \Phi) \\
&= -i\int_{\Sigma_0} d^3 x \sqrt{h} n^a \big{(} \sum_j \left[ \bar{B}_{ij} \psi_j + \bar{A}_{ij} \bar{\psi}_{j} \right] (d\Phi)_a \\
&\quad\quad\quad\quad- \Phi \sum_j \left[ \bar{B}_{ij} (d\psi_j)_a + \psi_j (d\bar{B}_{ij})_a + \bar{A}_{ij} (d\bar{\psi}_j)_a + \bar{\psi}_j (d\bar{A}_{ij})_a \right] \big{)}
\end{align*}using the Bogoliubov transformation ##\bar{\psi}_i' = \sum_j \left[ \bar{B}_{ij} \psi_j + \bar{A}_{ij} \bar{\psi}_j \right]##. Is that right, and if so what's the next step toward the result? Thanks and sorry if I'm missing something obvious, I'm not really familiar with any of this subject.
a_i' &= \int_{\Sigma_0} d^3 x \sqrt{h} n^a j_a(\psi_i', \Phi) \\
&= -i\int_{\Sigma_0} d^3 x \sqrt{h} n^a \big{(} \sum_j \left[ \bar{B}_{ij} \psi_j + \bar{A}_{ij} \bar{\psi}_{j} \right] (d\Phi)_a \\
&\quad\quad\quad\quad- \Phi \sum_j \left[ \bar{B}_{ij} (d\psi_j)_a + \psi_j (d\bar{B}_{ij})_a + \bar{A}_{ij} (d\bar{\psi}_j)_a + \bar{\psi}_j (d\bar{A}_{ij})_a \right] \big{)}
\end{align*}using the Bogoliubov transformation ##\bar{\psi}_i' = \sum_j \left[ \bar{B}_{ij} \psi_j + \bar{A}_{ij} \bar{\psi}_j \right]##. Is that right, and if so what's the next step toward the result? Thanks and sorry if I'm missing something obvious, I'm not really familiar with any of this subject.