Estimating rank-one matrices with mismatched prior and noise: universality and large deviations
Alice Guionnet, Justin Ko, Florent Krzakala, Lenka Zdeborová
TL;DR
This work addresses rank-one matrix estimation under mismatched priors and channels, establishing a universality principle that reduces general inference to a Gaussian SK-type model with parameters \bar{\beta} determined by generalized Fisher information. It proves an almost-sure large deviation principle for overlaps (the Franz–Parisi potential) and shows that these deviations—and hence the free-energy limit—are universal across noise models, including non-Gaussian channels. The core methodology combines Taylor expansion universality, Guerra interpolation, the cavity method, and the Ghirlanda–Guerra identities, culminating in a Parisi-type variational formula for the limiting free energy. The results unify a broad class of problems (e.g., spiked Wigner, submatrix localization, BBP) under a common variational framework and illuminate information–algorithmic gaps via the Franz–Parisi potential, with implications for understanding phase diagrams in mismatched inference. Overall, the paper provides a rigorous bridge from general mismatched inference to Gaussian-based analysis, delivering precise asymptotics for both the free energy and the overlaps.
Abstract
We prove a universality result that reduces the free energy of rank-one matrix estimation problems in the setting of mismatched prior and noise to the computation of the free energy for a modified Sherrington-Kirkpatrick spin glass. Our main result is an almost sure large deviation principle for the overlaps between the truth signal and the estimator for both the Bayes-optimal and mismatched settings. Through the large deviations principle, we recover the limit of the free energy in mismatched inference problems and the universality of the overlaps.
