Marshall sign and the doped $t-J$ model

TL;DR

This paper investigates the Marshall sign in doped antiferromagnets, revealing a zero spectral weight caused by phase strings, and introduces a non-perturbative scheme to access the ground state of the doped t-J model.

Contribution

It presents a novel non-perturbative approach that eliminates phase strings, enabling direct access to the ground state of the doped t-J model in one and two dimensions.

Findings

Zero spectral weight Z is linked to phase strings in doped antiferromagnets.

Elimination of phase strings through nonlocal transformations.

Formalism provides a new way to study the ground state of the doped t-J model.

Abstract

Marshall sign as a sole source of sign problem hidden in an antiferromagnet is explored under doping. By tracking the Marshall sign, a zero spectral weight $Z$ is revealed in the doped antiferromagnetic system. $Z=0$ is caused by a phase string induced by the ``bare'' hole. By eliminating such a phase string through nonlocal transformations, a non-perturbative scheme is obtained. It is argued that this formalism provides a unique way to get access to the real ground state of the doped $t-J$ model for both one- and two-dimensions.