# Experimental observation of Bethe strings

@article{Wang2018ExperimentalOO, title={Experimental observation of Bethe strings}, author={Zhe Wang and Jianda Wu and Wang Yang and Anup Kumar Bera and Dmytro Kamenskyi and Atm Nazmul Islam and Shenglong Xu and Joseph M. Law and Bella Lake and Congjun Wu and Alois Loidl}, journal={Nature}, year={2018}, volume={554}, pages={219-223} }

Almost a century ago, string states—complex bound states of magnetic excitations—were predicted to exist in one-dimensional quantum magnets. However, despite many theoretical studies, the experimental realization and identification of string states in a condensed-matter system have yet to be achieved. Here we use high-resolution terahertz spectroscopy to resolve string states in the antiferromagnetic Heisenberg–Ising chain SrCo2V2O8 in strong longitudinal magnetic fields. In the field-induced…

## 62 Citations

Dispersions of many-body Bethe strings

- Physics
- 2019

Complex bound states of magnetic excitations, known as Bethe strings, were predicted almost a century ago to exist in one-dimensional quantum magnets 1 . The dispersions of the string states have so…

One-dimensional quantum spin dynamics of Bethe string states

- PhysicsPhysical Review B
- 2019

Quantum dynamics of strongly correlated systems is a challenging problem. Although the low energy fractional excitations of one dimensional integrable models are often well-understood, exploring…

Quantum Critical Dynamics of a Heisenberg-Ising Chain in a Longitudinal Field: Many-Body Strings versus Fractional Excitations.

- PhysicsPhysical review letters
- 2019

A high-resolution terahertz spectroscopic study of quantum spin dynamics in the antiferromagnetic Heisenberg-Ising spin-chain compound BaCo-V-O-8 as a function of temperature and longitudinal magnetic field finds the high-energy string excitations are found to have a dominant contribution to the spin dynamics as compared with the fractional excitations.

Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO3

- PhysicsNature communications
- 2021

This work investigates the Heisenberg spin-chain compound YbAlO3 and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems.

Dynamical Signatures of Quasiparticle Interactions in Quantum Spin Chains.

- PhysicsPhysical review letters
- 2020

In the high magnetization regime, as the Zeeman field approaches the saturation value, the appearance of two-magnon bound states in the transverse susceptibility is uncovered, which generalizes the one arising from string states inThe Bethe ansatz solution of the integrable case.

Real-time dynamics of string breaking in quantum spin chains

- PhysicsPhysical review. B
- 2020

It is shown that string breaking can be observed in quantum Ising chains where domain walls get confined either by a symmetry-breaking field or by long-range interactions, and an effective description of this motion is developed, which is strongly constrained.

Experimental observation of quantum many-body excitations of
E8
symmetry in the Ising chain ferromagnet
CoNb2O6

- Physics
- 2020

Close to the quantum critical point of the transverse-field Ising spin-chain model, an exotic dynamic spectrum was predicted to emerge upon a perturbative longitudinal field. The dynamic spectrum…

Fractional and composite excitations of antiferromagnetic quantum spin trimer chains

- Physicsnpj Quantum Materials
- 2022

Using quantum Monte Carlo, exact diagonalization, and perturbation theory, we study the spectrum of the S = 1/2 antiferromagnetic Heisenberg trimer chain by varying the ratio g = J 2 / J 1 of the…

Confinement in the spectrum of a Heisenberg–Ising spin ladder

- PhysicsJournal of Statistical Mechanics: Theory and Experiment
- 2020

The Heisenberg–Ising spin ladder is one of the few short-range models showing confinement of elementary excitations without the need of an external field, neither transverse nor longitudinal. This…

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