Analytic continuation over complex landscapes

TL;DR

This paper explores the topological and spectral properties of complex landscapes, revealing how their stationary points' stability and analytic continuation are influenced by the spectrum of the Hessian, with implications for different landscape structures.

Contribution

It introduces a spectral perspective on complex landscapes, identifying how Hessian spectra influence topological changes and Stokes points, and defines a new matrix ensemble relevant to these landscapes.

Findings

Gap in Hessian spectrum indicates topological stability.

Threshold energy separates different saddle types.

New matrix ensemble characterizes complex landscape saddles.

Abstract

In this paper we follow up the study of 'complex complex landscapes,' rugged landscapes of many complex variables. Unlike real landscapes, the classification of saddles by index is trivial. Instead, the spectrum of fluctuations at stationary points determines their topological stability under analytic continuation of the theory. Topological changes, which occur at so-called Stokes points, proliferate among saddles with marginal (flat) directions and are suppressed otherwise. This gives a direct interpretation of the gap or 'threshold' energy -- which in the real case separates saddles from minima -- as the level where the spectrum of the hessian matrix of stationary points develops a gap. This leads to different consequences for the analytic continuation of real landscapes with different structures: the global minima of 'one step replica-symmetry broken' landscapes lie beyond a threshold, their hessians are gapped, and are locally protected from Stokes points, whereas those of 'many step replica-symmetry broken' have gapless hessians and Stokes points immediately proliferate. A new matrix ensemble is found, playing the role that GOE plays for real landscapes in determining the topological nature of saddles.