# Microscopic spinon-chargon theory of magnetic polarons in the t-J model

## TL;DR

This paper develops a microscopic spinon-chargon theory for magnetic polarons in the t-J model, explaining doped holes as bound states with hidden string order, supported by numerical simulations and relevant to high-Tc superconductors.

## Contribution

It introduces a trial wavefunction for holes in an AFM, providing a microscopic basis for meson-like spinon-chargon bound states and connecting geometric string theory with numerical results.

## Key findings

- Good agreement with numerical simulations for ground state energy and dispersion
- Evidence of short-range hidden string order at zero temperature
- Extension to systems with short-range magnetic correlations

## Abstract

The interplay of spin and charge degrees of freedom, introduced by doping mobile holes into a Mott insulator with strong anti-ferromagnetic (AFM) correlations, is at the heart of strongly correlated matter such as high-Tc cuprate superconductors. Here we capture this interplay in the strong coupling regime and propose a trial wavefunction of mobile holes in an AFM. Our method provides a microscopic justification for a class of theories which describe doped holes moving in an AFM environment as meson-like bound states of spinons and chargons. We discuss a model of such bound states from the perspective of geometric strings, which describe a fluctuating lattice geometry introduced by the fast motion of the chargon. This is demonstrated to give rise to short-range hidden string order, signatures of which have recently been revealed by ultracold atom experiments. We present evidence for the existence of such short-range hidden string correlations also at zero temperature by performing numerical DMRG simulations. To test our microscopic approach, we calculate the ground state energy and dispersion relation of a hole in an AFM, as well as the magnetic polaron radius, and obtain good quantitative agreement with advanced numerical simulations at strong couplings. We discuss extensions of our analysis to systems without long range AFM order to systems with short-range magnetic correlations.