Variational wave functions for frustrated magnetic models

TL;DR

This paper explores the versatility of projected BCS variational wave functions in accurately describing various quantum phases, including disordered, dimerized, and magnetically ordered states, in low-dimensional magnetic systems.

Contribution

It demonstrates that a unified class of variational wave functions can effectively model multiple quantum phases in one and two dimensions, including magnetic and superconducting orders.

Findings

Projected wave functions accurately describe different quantum phases.

Magnetic order can be incorporated with superconducting and spin correlations.

Unified variational approach applies to disordered and ordered magnetic states.

Abstract

Variational wave functions containing electronic pairing and suppressed charge fluctuations (i.e., projected BCS states) have been proposed as the paradigm for disordered magnetic systems (including spin liquids). Here we discuss the general properties of these states in one and two dimensions, and show that different quantum phases may be described with high accuracy by the same class of variational wave functions, including dimerized and magnetically ordered states. In particular, phases with magnetic order may be obtained from a straightforward generalization containing both antiferromagnetic and superconducting order parameters, as well as suitable spin Jastrow correlations. In summary, projected wave functions represent an extremely flexible tool for understanding the physics of low-dimensional magnetic systems.