Half-ice, half-fire driven ultranarrow phase crossover in 1D decorated q-state Potts ferrimagnets: An AI-co-led exploration

TL;DR

This study analytically explores ultranarrow phase crossovers in 1D decorated q-state Potts ferrimagnets, revealing novel features like dome structures and multiple UNPCs, with AI-driven insights into their behavior and potential applications.

Contribution

The paper presents the first exact analytic investigation of ultranarrow phase crossovers in decorated q-state Potts models, highlighting AI-led discovery of new phenomena and phase behaviors.

Findings

Persistence of ultranarrow phase crossover for q > 2

Identification of dome structure in phase diagram

Dependence of crossover temperature on interaction J

Abstract

OpenAI's reasoning model o3-mini-high was used to carry out an exact analytic study of onedimensional ferrimagnetic site- and bond-decorated q-state Potts models. We demonstrate that the finitetemperature ultranarrow phase crossover (UNPC), driven by a hidden "half-ice, half-fire" state recently discovered in the $q = 2$ case (Ising model), persists for $q > 2$. We identify unique novel features for $q > 2$, including the dome structure in the field-temperature phase diagram and for large $q$ a secondary high-temperature UNPC to the fully disordered paramagnetic state. Moreover, while the crossover temperature $T_0$ in the site-decorated Potts model is independent of the spin interaction $J$ between the backbone spins and thus remains unchanged as the UNPC quickly approaches a genuine transition -- the crossover width is narrowed exponentially -- by enhancing $J$ (referred to as Type-I UNPC), $T_0$ in the bond-decorated Potts model with $q > 2$ depends on $J$ and quickly shifts toward a finite temperature as $J$ increases (referred to as Type-II UNPC). These novel results establish a versatile framework for engineering controlled fast state-flipping switches in low-dimensional systems. Our nine-level AI-contribution rating assigns AI the meritorious status of AI-co-led discovery in this work.