Soft confinement in a 3-d spin system

TL;DR

This paper models a 3D spin system with a non-linear sigma model interacting with fermions, revealing supercriticality and soft confinement phenomena that suggest a new type of spin polaron potentially leading to exotic superconductivity.

Contribution

It introduces a nonperturbative Yukawa coupling approach to describe soft confinement in a 3D spin system, analogous to Gribov's confinement theory.

Findings

Demonstrates supercriticality and soft confinement in the model.

Identifies a new type of spin polaron.

Suggests potential for exotic superconductivity.

Abstract

We consider a 1+3 dimensional spin system. The spin-wave (magnon) field is described by the O(3) non-linear sigma model with a symmetry-breaking potential. This interacts with a slow spin SU(2) doublet Schrodinger fermion. The interaction is described by a generalized nonperturbative Yukawa coupling, and the self-consistency condition is solved with the aid of a non-relativistic Gribov equation. When the Yukawa coupling is sufficiently strong, the solution exhibits supercriticality and soft confinement, in a way that is quite analogous to Gribov's light-quark confinement theory. The solution corresponds to a new type of spin polaron, whose condensation may lead to exotic superconductivity.