# Mutually attracting spin waves in the square-lattice quantum antiferromagnet

## TL;DR

This paper demonstrates that in the square-lattice quantum antiferromagnet, dressed magnons exhibit strong mutual attraction at short distances, providing a comprehensive understanding aligned with experimental observations, crucial for high-temperature superconductor research.

## Contribution

It introduces a model of dressed magnons with mutual attraction to explain short-range processes in the Heisenberg model, challenging the fractional spinon perspective.

## Key findings

- Spectral signatures match experimental data.
- Magnons exhibit strong mutual attraction at short distances.
- Provides a unified picture of spin excitations in the model.

## Abstract

The Heisenberg model for S=1/2 describes the interacting spins of electrons localized on lattice sites due to strong repulsion. It is the simplest strong-coupling model in condensed matter physics with wide-spread applications. Its relevance has been boosted further by the discovery of curate high-temperature superconductors. In leading order, their undoped parent compounds realize the Heisenberg model on square-lattices. Much is known about the model, but mostly at small wave vectors, i.e., for long-range processes, where the physics is governed by spin waves (magnons), the Goldstone bosons of the long-range ordered antiferromagnetic phase. Much less, however, is known for short-range processes, i.e., at large wave vectors. Yet these processes are decisive for understanding high-temperature superconductivity. Recent reports suggest that one has to resort to qualitatively different fractional excitations, spinons. By contrast, we present a comprehensive picture in terms of dressed magnons with strong mutual attraction on short length scales. The resulting spectral signatures agree strikingly with experimental data