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-rw-r--r--main.tex20
1 files changed, 8 insertions, 12 deletions
diff --git a/main.tex b/main.tex
index 706b74f..a53e0ff 100644
--- a/main.tex
+++ b/main.tex
@@ -267,22 +267,18 @@ diagrams for this model are shown in Figure \ref{fig:phases}.
The susceptibility is given by
\begin{equation}
\begin{aligned}
- &\chi_{ij}^{-1}(x,x')
- =\frac{\delta^2F}{\delta\eta_i(x)\delta\eta_j(x')} \\
- &\quad=\Big[\big(\tilde r-c_\parallel\nabla_\parallel^2
- -c_\perp\nabla_\perp^2+D_\perp\nabla_\perp^4+4u\eta^2(x)\big)\delta_{ij} \\
- &\qquad\qquad +8u\eta_i(x)\eta_j(x)\Big]\delta(x-x'),
+ &\chi^{-1}(x,x')
+ =\frac{\delta^2F}{\delta\eta(x)\delta\eta(x')}
+ =\big(\tilde r-c_\parallel\nabla_\parallel^2-c_\perp\nabla_\perp^2 \\
+ &\qquad\qquad+D_\perp\nabla_\perp^4+12u\eta^2(x)\big)
+ \delta(x-x'),
\end{aligned}
\end{equation}
or in Fourier space,
\begin{equation}
- \begin{aligned}
- \chi_{ij}^{-1}(q)
- &=8u\sum_{q'}\tilde\eta_i(q')\eta_j(-q')+\bigg(\tilde r
- +c_\parallel q_\parallel^2-c_\perp q_\perp^2 \\
- &\qquad+D_\perp q_\perp^4+4u\sum_{q'}\tilde\eta_k(q')\tilde\eta_k(-q')\bigg)
- \delta_{ij}.
- \end{aligned}
+ \chi^{-1}(q)
+ =\tilde r+c_\parallel q_\parallel^2-c_\perp q_\perp^2+D_\perp q_\perp^4
+ +12u\sum_{q'}\tilde\eta_{q'}\tilde\eta_{-q'}.
\end{equation}
Near the unordered--modulated transition this yields
\begin{equation}