Exact ground state for 1D electronic models

TL;DR

This paper presents the exact ground states for two 1D electronic models, revealing giant spiral magnetic and superconducting orders, and proposes these as key to understanding phase transitions in such systems.

Contribution

It provides the first exact solutions for the ground states of two specific 1D electronic models at critical points, highlighting giant spiral order phenomena.

Findings

Giant spiral magnetic order at ferromagnet--antiferromagnet transition.

Giant spiral off-diagonal long-range order indicating superconductivity.

Ground states suggest a common mechanism for destruction of ferromagnetism and superconductivity.

Abstract

We have found the exact ground state for two electronic models on a linear chain. The first model describes half-filling electron system in the ferromagnet--antiferromagnet transition point. In the singlet ground state the spin correlators show giant spiral magnetic ordering with the period of a spiral equals to the system size. The second electronic model describes the point where the ground state has giant spiral off-diagonal long-range order and, therefore, superconducting. We suggest the formation of the ground state with giant spiral order (ferromagnetic or off-diagonal) as a probable scenario of the subsequent destruction of the ferromagnetism and the superconductivity.