Relation between high-energy quasiparticles of quasi-one-dimensional antiferromagnets in a magnetic field and a doublon of a Hubbard chain

TL;DR

This paper explores the origin of high-energy quasiparticle states in one-dimensional antiferromagnets under magnetic fields, linking them to Hubbard model doublons via Bethe ansatz solutions.

Contribution

It reveals that high-energy states in these antiferromagnets are analogous to Hubbard model doublons, explained through string solutions of the Bethe ansatz, providing a new theoretical understanding.

Findings

High-energy states are linked to Hubbard model doublons.

Bethe ansatz string solutions explain the high-energy spectral weight.

The mechanism is distinct from Nambu-Goldstone bosons or Luttinger liquids.

Abstract

In spin-1/2 one-dimensional Heisenberg antiferromagnets and anisotropic triangular Heisenberg antiferromagnets, high-energy states carrying considerable spectral weights have been observed in a magnetic field using inelastic neutron scattering. Such high-energy properties cannot be explained in terms of either Nambu-Goldstone bosons due to spontaneous breaking of continuous symmetries or quasiparticles in a Tomonaga-Luttinger liquid. Here, we show that the mechanism causing the high-energy states is analogous to that of the upper Hubbard band in the one-dimensional Hubbard model, by theoretically tracing the origin of the high-energy states back to string solutions of the Bethe ansatz.