Variational study of J1-J2 Heisenberg model on Kagome lattice using projected Schwinger boson wave functions

TL;DR

This study uses variational Monte Carlo to compare Schwinger boson wave functions in the J1-J2 Kagome Heisenberg model, revealing a lower energy state for certain parameters and demonstrating the effectiveness of bosonic approaches.

Contribution

It introduces a comparative analysis of bosonic and fermionic wave functions in the J1-J2 Kagome model, highlighting the viability of Schwinger boson states.

Findings

Sachdev's Q1=Q2 SB ansatz has lower energy for J2 > 0.08 J1

Projected SB wave functions are competitive with fermionic methods

Identification of energetically favorable states in the J1-J2 Kagome model

Abstract

Motivated by the unabating interest in the spin-1/2 Heisenberg antiferromagnetic model on the Kagome lattice, we investigate the energetics of projected Schwinger boson (SB) wave functions in the $J_1$--$J_2$ model with antiferromagnetic $J_2$ coupling. Our variational Monte Carlo results show that Sachdev's $Q_1=Q_2$ SB ansatz has a lower energy than the Dirac spin liquid for $J_2\gtrsim 0.08 J_1$ and the ${\bf q=0}$ Jastrow type magnetically ordered state. This work demonstrates that the projected SB wave functions can be tested on the same footing as their fermionic counterparts.