From 35f67091ec755281f38898aaff9b9d23610c43af Mon Sep 17 00:00:00 2001 From: Jaron Kent-Dobias Date: Mon, 7 Feb 2022 12:22:03 +0100 Subject: Changed order of paragraphs. --- stokes.tex | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/stokes.tex b/stokes.tex index ce01b52..3c8af84 100644 --- a/stokes.tex +++ b/stokes.tex @@ -442,22 +442,6 @@ eigenvalue problem. If we did not know the eigenvalues were real, we could still see it from the second implied equation, $(\beta\partial\partial\mathcal S)^*v^*=\lambda v$, which is the conjugate of the first if $\lambda^*=\lambda$. -The effect of changing the phase of $\beta$ is revealed by -\eqref{eq:generalized.eigenproblem}. Writing $\beta=|\beta|e^{i\phi}$ and -dividing both sides by $|\beta|e^{i\phi/2}$, one finds -\begin{equation} - \partial\partial\mathcal S(e^{i\phi/2}v) - =\frac{\lambda}{|\beta|}e^{-i\phi/2}v^* - =\frac{\lambda}{|\beta|}(e^{i\phi/2}v)^* -\end{equation} -Therefore, one only needs to consider solutions to the eigenproblem for the -action alone, $\partial\partial\mathcal Sv_0=\lambda_0 v_0^*$, and then rotate the -resulting vectors by a constant phase corresponding to half the phase of -$\beta$ or $v(\phi)=v_0e^{-i\phi/2}$. One can see this in the examples of Figs. \ref{fig:1d.stokes} and -\ref{fig:thimble.orientation}, where increasing the argument of $\beta$ from -left to right produces a clockwise rotation in the thimbles in the -complex-$\theta$ plane. - Something somewhat hidden in the structure of the real hessian but more clear in its complex form is that each eigenvalue comes in a pair, since \begin{equation} @@ -474,6 +458,22 @@ real eigenvectors which determine its index in the real problem are accompanied by $N$ purely imaginary eigenvectors, pointing into the complex plane and each with the negative eigenvalue of its partner. +The effect of changing the phase of $\beta$ is revealed by +\eqref{eq:generalized.eigenproblem}. Writing $\beta=|\beta|e^{i\phi}$ and +dividing both sides by $|\beta|e^{i\phi/2}$, one finds +\begin{equation} + \partial\partial\mathcal S(e^{i\phi/2}v) + =\frac{\lambda}{|\beta|}e^{-i\phi/2}v^* + =\frac{\lambda}{|\beta|}(e^{i\phi/2}v)^* +\end{equation} +Therefore, one only needs to consider solutions to the eigenproblem for the +action alone, $\partial\partial\mathcal Sv_0=\lambda_0 v_0^*$, and then rotate the +resulting vectors by a constant phase corresponding to half the phase of +$\beta$ or $v(\phi)=v_0e^{-i\phi/2}$. One can see this in the examples of Figs. \ref{fig:1d.stokes} and +\ref{fig:thimble.orientation}, where increasing the argument of $\beta$ from +left to right produces a clockwise rotation in the thimbles in the +complex-$\theta$ plane. + These eigenvalues and vectors can be further related to properties of the complex symmetric matrix $\beta\partial\partial\mathcal S$. Suppose that $u\in\mathbb R^N$ satisfies the eigenvalue equation -- cgit v1.2.3-70-g09d2