summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--when_annealed.tex48
1 files changed, 32 insertions, 16 deletions
diff --git a/when_annealed.tex b/when_annealed.tex
index 6e63ded..ae7e3b8 100644
--- a/when_annealed.tex
+++ b/when_annealed.tex
@@ -135,11 +135,11 @@ temperature.\footnote{
This is a very strong condition on the form of equilibrium order. Note that
non-convex $f$ does not imply that you will see nontrivial correlations between
states at some temperature. In the $3+s$ models we consider here, models with
-$s>8$ have non-convex $f$ and those with $s\geq8$ have convex $f$ independent
+$s>8$ have non-convex $f$ and those with $s\leq8$ have convex $f$ independent
of $\lambda$. Second, the characterization of the ground state has been made
\cite{Crisanti_2004_Spherical, Crisanti_2006_Spherical,
Crisanti_2011_Statistical, Auffinger_2022_The}. In the $3+s$ models we
-consider, for $s>12.430\ldots$ nontrivial ground state configurations appear in
+consider, for $s>12.430...$ nontrivial ground state configurations appear in
certain ranges of $\lambda$. These bounds on equilibrium order are shown in
Fig.~\ref{fig:phases}, along with our result in this paper for where the
complexity has nontrivial \textsc{rsb}. As evidenced in that figure,
@@ -166,12 +166,12 @@ $\mu=\mu_\mathrm m$, the spectrum has a pseudogap, and we have marginal minima.
\caption{
A phase diagram of the boundaries we discuss in this paper for the $3+s$
model with $f=\frac12\big(\lambda q^3+(1-\lambda)q^s\big)$. The blue region
- shows where there exist some stationary points whose complexity is
- {\oldstylenums1}\textsc{rsb}, and is given by $G_f>0$ where $G_f$ is found
- in \eqref{eq:condition}. The yellow region shows where $f$ is not convex
- and therefore \textsc{rsb} solutions are possible in equilibrium. The green
- region shows where \textsc{rsb} solutions are correct at the ground state,
- adapted from \cite{Auffinger_2022_The}.
+ shows models which have some stationary points with nontrivial
+ {\oldstylenums1}\textsc{rsb} structure, and is given by $G_f>0$ where $G_f$
+ is found in \eqref{eq:condition}. The yellow region shows where $f$ is not
+ convex and therefore nontrivial \textsc{rsb} solutions are possible in
+ equilibrium. The green region shows where \textsc{rsb} solutions are
+ correct at the ground state, adapted from \cite{Auffinger_2022_The}.
} \label{fig:phases}
\end{figure}
@@ -278,7 +278,9 @@ solution for points describing saddles ($\mu<\mu_\mathrm m$), this line is
\begin{equation} \label{eq:extremal.line}
\mu_0=-\frac1{z_f}\left(2Ef'f''+\sqrt{2f''u_f\bigg(\log\frac{f''}{f'}z_f-E^2(f''-f')\bigg)}\right)
\end{equation}
-where we define for brevity (here and elsewhere) the constants
+where we have chosen the lower branch as a convention (see
+Fig.~\ref{fig:complexity_35}) and where we define for brevity (here and
+elsewhere) the constants
\begin{align}
u_f&=f(f'+f'')-f'^2
&&
@@ -294,14 +296,16 @@ these constants are positive. We also define $E_\textrm{min}$, the minimum
energy at which saddle points with an extensive number of downward directions
are found, as the energy for which $\mu_0(E_\mathrm{min})=\mu_\mathrm m$.
-Let $M$ be the matrix of double partial derivatives of $\mathcal S$ with
+Let $M$ be the matrix of double partial derivatives of the action with
respect to $q_1$ and $x$. We evaluate $M$ at the replica symmetric saddle point
$x=1$ with the additional constraint that $q_1=1$ and along the extremal
complexity line \eqref{eq:extremal.line}. We determine when a zero eigenvalue
appears, indicating the presence of a bifurcating {\oldstylenums1}\textsc{rsb}
solution, by solving $0=\det M$. We find
\begin{equation}
- \det M=-\bigg(\frac{\partial^2\mathcal S}{\partial q_1\partial x}\bigg|_{\substack{x=1\\q_1=1}}\bigg)^2\propto(ay^2+bE^2+2cyE-d)^2
+ \det M
+ =-\bigg(\frac{\partial^2\mathcal S_{\oldstylenums1\textsc{rsb}}}{\partial q_1\partial x}\bigg|_{\substack{x=1\\q_1=1}}\bigg)^2
+ \propto(ay^2+bE^2+2cyE-d)^2
\end{equation}
where $y=-\frac12z_f\mu-f'f''E$ is proportional to the square-root term in
\eqref{eq:extremal.line} and the constants $a$, $b$, $c$, and $d$ are defined
@@ -464,7 +468,7 @@ extended from $E_{\oldstylenums1\textsc{rsb}}^+$.
There are implications for the emergence of \textsc{rsb} in equilibrium. Consider a specific $H$ with
\begin{equation}
H(\pmb\sigma)
- =\frac{\sqrt\lambda}{p!}\sum_{i_1\cdots i_p}J^{(p)}_{i_1\cdots i_p}\sigma_{i_1}\cdots\sigma_{i_2}
+ =\frac{\sqrt\lambda}{p!}\sum_{i_1\cdots i_p}J^{(p)}_{i_1\cdots i_p}\sigma_{i_1}\cdots\sigma_{i_p}
+\frac{\sqrt{1-\lambda}}{s!}\sum_{i_1\cdots i_s}J^{(s)}_{i_1\cdots i_s}\sigma_{i_1}\cdots\sigma_{i_s}
\end{equation}
where the interaction tensors $J$ are drawn from zero-mean normal distributions
@@ -497,18 +501,24 @@ $s>2$, this transition line \emph{always} intersects the extremal line
among some population of stationary points. However, it is likely that for much
of the parameter space the so-called one-full \textsc{rsb}
({\oldstylenums1\textsc{frsb}}) is the correct solution, as it likely is for
-large $s$ in the $3+s$ model at hand. Further work to find the conditions for
-transitions of the complexity to these forms of order is necessary.
+large $s$ in the $3+s$ model at hand. Further work to find the
+conditions for transitions of the complexity to these forms of order is
+necessary. For values of $s$ where there is no
+\textsc{rsb} of any kind in the ground state, we expect that the
+{\oldstylenums1\textsc{rsb}} complexity is correct.
What are the implications for dynamics? We find that nontrivial correlations
tend to exist among saddle points with the maximum or minimum index possible at
a given energy density, which are quite atypical in the landscape. However,
these strangely correlated saddle points must descend to uncorrelated minima,
which raises questions about whether structure on the boundary of a basin of
-attraction is influential to the dynamics that descends into that basin. These saddles might act as early-time separatrices for descent trajectories. With
+attraction is influential to the dynamics that descends into that basin. These
+saddles might act as early-time separatrices for descent trajectories. With
large open problems in even the gradient decent dynamics on these models, it
remains to be seen whether such structures could be influential
-\cite{Folena_2020_Rethinking, Folena_2023_On}.
+\cite{Folena_2020_Rethinking, Folena_2023_On}. This structure among saddles
+cannot be the only influence, since it seems that the $3+4$ model is `safe'
+from nontrivial \textsc{rsb} among saddles.
We have determined the conditions under which the complexity of the mixed $3+s$
spherical models has different quenched and annealed averages, as the result of
@@ -517,6 +527,12 @@ can arise among certain populations of saddle points even when the model is
guaranteed to lack such correlations between equilibrium states, and exist for
saddle points at a wide range of energies.
+
+\paragraph{Funding information}
+
+JK-D is supported by a \textsc{DynSysMath} Specific Initiative of the
+INFN.
+
\printbibliography
\end{document}